PG Classroom - Seminar - Controversies in Labour Management

TOPICS COVERED

 

 1.     CONTROVERSIES IN THE METHODS OF CERVICAL RIPENING

 2.      CONTROVERSY IN ACTIVE MANAGEMENT OF LABOR

 3.      CONTROVERSIES IN RISING RATES OF CAESAREAN BIRTHS

 4.      V.B.A.C.

 5.      CONTROVERSIES SURROUNDING ROUTINE USE OF EPISIOTOMY

 6.      CONTROVERSIES SURROUNDING THE INTRA PARTUM MANAGEMENT OF TWINS

 7.      CONTROVERSIES IN CONGENITAL ANOMALIES AND THE ROUTE OF DELIVERY

 

METHODS OF CERVICAL RIPENING

 

VARIOUS METHODS OF CERVICAL RIPENING:

1) Stripping membranes

Method: The technique involves placing the examining digit through the internal cervical OS and then mechanically separating chorioamniotic membranes from the internal surface of the lower uterus by sweeping the digit circumferentially.

Mechanism of action:  A rapid increasing in PGF concentration in plasma after stripping. An increasing level of PGF2a and endocervical phospholipase A2 has been documented. This elevation lasted 2 hours and was followed by increase in uterine contraction frequency 3 to 4 hours later.

Advantages

2)                  Non invasive technique

3)                  Inexpensive

4)                  Easy procedure

5)                  Can be done on OPD base.

6)                  Can be repeated weekly

Disadvantages

1)                  Chances of ARM

2)                  Infection

3)                  Bleeding from low lying placenta

4)                  Painful procedure

 

2) HYGROSCOPIC DILATORS:

Natural                           Synthetic

Laminaria tent                         Dilpan

(Derived from dried                Lamicel

sea wood)

Available length:                    60 mm.

Available diameter:               2 to 6 mm.

Procedure:                             This material is inserted in cervical canal under direct  visualization using aseptic precaution.

Mechanism of action: By placing the tent in the cervix, it takes up fluid from the surrounding tissue. The tent swells up slowly leading to dilation of cervix which in turn leads to prostaglandin release.

Advantages

1)                  Inexpensive

2)                  Easy to use

Disadvantages

1)                  Infection

2)                  Not used in PROM, cervicitis, vaginal bleeding, prior C.S.

3)                  Increasing chance of maternal endometritis, neonatal sepsis.

 

 

3)         BALLOON CATHETER:

·         Older method

            Now a day’s simple Foley’s catheters are also used.

Procedure:     Thorough cleaning of vagina and cervix. Catheter inserted into endocervix    

and passed above the level of internal OS. Inflate the balloon of the catheter with 30 to 50 ml of sterile saline and is pulled gently to the level of internal os. It is kept for 4 to 24 hrs or up to spontaneous expulsion

                        Addition = adding traction on catheter

                                    = infuse 1 ml/min saline extramniotically

Mechanism of Action:

1)                  Direct pressure and overstretching of lower uterine segment of cervix.

2)                  Increasing local secretion of prostaglandins.

Disadvantages:

a)                  Not used in cases of low lying placenta, previous LSC.S., cervicitis, premature rupture of membranes.

b)                  Increase chance of ascending infection.

 

Advantages:

a)                  Low cost

b)                  Simple procedure

c)                  Reversibility

d)                 Less side effects

 

4) RELAXIN:

            Human relaxin is a peptide hormone containing two disulfide bonds.

Mechanism of action:            Increasing cervical ripening by increasing collagenase activity and glycosaminoglycan synthesis.

Available in 2 types:

1) Purified porcine relaxing gel (1 to 4 mg content)

Route:             Intra vaginal

                        Intra cervical

2) 1.5 mg recombinant human relaxin

Route:             Intra vaginal: Not effective

                        Intra cervical 

5) MIFIPRISTONE:

-          Available as 200 mg tablets

-          Artificial steroidal drug with antiprogesterone and antiglucocorticoid activity.

-          Orally well absorbable

-          Half life 25 to 30 hours

-          Most useful induction agent in IUFD.

How to Give:

Tablet Mifepristone orally 1st day 200 mg à on day 4 induction of labor by PGE2 gel / amniotomy / oxytocin

Advantages:

1)                  Rapidly absorbed

2)                  Longer half life

3)                  Used in IUFD

4)                  Also useful in previous LSC.S..

 

6) MISOPROSTOL

            Available as 100 ug and 200 ug tab

            PGE analogue, inexpensive

Route: Oral, intra vaginal

How to give: Intra vaginal 25 μg, 50 μg, 100 μ

Orally: 100 μg or 200 μg

Advantages:

1)      Can be given orally or vaginally

2)      Relatively cheap

Disadvantages:

1)                  Nausea, Vomiting

2)                  Tachysystole, hypertonus uterus

3)                  Contraindicated in previous C.S.

 7) PGE2GEL:

Prostaglandins are used intravaginally. PGE2 AND PGF2a  has more uterine hyperstimulation, GI disturbances and so increased chances of vomiting and diarrhea

- Intra-vaginal gel 0.5 mg PGE2

- Intra vaginal 25 mg of PGF2a – less effective

 

8) SEXUAL INTERCOURSE:

1) Penetration

2) Breast stimulation

3) Semen

Lower segment of uterus stimulated.

Oxytocin increased

Rich source of prostaglandin

                                               

All above three mechanisms lead to local release of prostaglandins. More data is not available on efficacy and rationale.

 

9) BREAST STIMULATION:

            Breast Massage                       Nipple Stimulation                  Breast Massage

            Release of oxytocin                                                                gentle massage

                                                                                                        warm compresses to

                                                                                                         breasts for 1 hr. / 3 

                                                                                                          times day

            More detail not available

 10) CASTER OIL / HOT BATHS AND ENEMAS

            Mechanism of action: Not known

            100 women with all these three method

            Poorly designed study à  no evidence to support the use of this modalities

 11) HERBAL SUPPLEMENTS:

-          Evening primrose oil, black hair, black and blue cohosh, red raspberry leaves.

-          Risks of benefits of all these things are not known therefore, quality of evidence is based on long term use by a certain population.

-          Role of all these things is uncertain.

 12) ACUPUNCTURE / TRANSCUTANEOUS NERVE STIMULATION:

-          Insertion of very fine needles into designated location with purpose of curing disease

-          It is said to stimulate the channel of energy. 

-          Their role in induction of labour is very controversial.

13) OESTROGEN:

-          In pregnant ewes pre-labor rise in estrogens leads to decrease in progesterone à Prostaglandins à initiate labor.

-          But research in human failed to demonstrate a similar physiological mechanism.

14) A.R.M.

15) OXYTOCIN

16) HYALURONIDAZE

17) STEROIDS

COCHRANE REVIEW

            The reviews included 45 trials using vaginal misoprostol for labor induction and 13 trials using oral misoprostol.

 Misoprostol versus Placebo

            Both Vaginal and oral misoprostol were more effective than placebo in cervical ripening and shortening the induction to delivery interval. The numbers studied were too small to assess the impact on obstetric management and maternal and neonatal complications.

 Misoprostol versus Oxytocin

-          Vaginal Misoprostol was more effective than oxytocin for labor induction (RR of failure to achieve vaginal delivery within 24 hours 0.57 at 95% CI). However, uterine hyperstimulation associated with fetal heart rate changes were common. There were fewer C.S. rate with vaginal misoprostol (RR 0.71 at CI of 95%) and no differences in perinatal or maternal adverse outcome.

-          Two small trials evaluating oral misoprostol showed no clinically statistically significant differences in pre-specified outcomes.

 Misoprostol Versus Intra-vaginal  Prostaglandins                                                                          

-          Oxytocin induction and failure to achieve vaginal delivery in 24 hours decreased with vaginal misoprostol

-          Uterine hyperstimulation with or without fetal heart rate changes and MSAF more common with misoprostol.

-          C.S. rates not consistent but vaginal assisted delivery were increased.

-          Perinatal, maternal outcomes not significantly different in comparison.

-          Results were similar with unfavorable cervices and also for primiparous or multiparous subgroups.

 

Oral Misoprostol versus Vaginal PG

-          Induction to delivery interval somewhat shorter

-          Pooled hyperstimulation rate with oral misoprostol was 4.3% vs. 4.9% for vaginal prostaglandins

-          C.S. rate was 18.3% and 20.3% respectively.

 Misoprostol versus Intra-cervical PG

-          12 trials included

-          Failure to achieve vaginal delivery in 24 hours, oxytocin augmentation reduced with misoprostol.

-          MSAF and uterine hyperstimulation was more common.

-          No consistent patterns for vaginal instrumental delivery or C.S.

-          No statistically significant difference in perinatal or maternal outcomes.

Oral misoprostol versus Intra-cervical PG

-          Single dose 200 mg oral misoprostol was more effective in achieving vaginal delivery in 24 hours (76% vs. 50%)

 Misoprostol High Dose versus Low Dose

-          Low dose regimen (25 mcg. 6 hourly versus 3 hourly) or 25 mcg versus 50 mcg 3 hourly) did not show significantly more failures to achieve vaginal delivery within 24 hours

-          More use of oxytocin in low dose group.

-          No difference in mode of delivery MSAF or maternal side effects.

-          Less cases of uterine hyperstimulation in low dose regimen

 Oral versus Vaginal Misoprostol

-          Oral Misoprostol less effective than vaginal misoprostol

-          50% women in oral group did not achieve vaginal delivery compared to 39.7% in vaginal misoprostol group.

-          C.S. rate in oral was 16.7% compared to 21.7% with vaginal misoprostol

-          No difference in uterine hyperstimulation with Fetal heart rate changes.

-          No reported cases of severe neonatal and maternal morbidity in either group.

-          Reviewers concluded that misoprostol shows promise as a highly effective, inexpensive and convenient agent for labor induction. However, apparent increase in uterine hyperstimulation and rare risk of rupture uterus are areas of concern.

-          It cannot be recommended for routine use at this stage. There is urgent need for trials to establish its safety.

 Mifipristone:

-          A randomized study of labor induction was carried out in 120 women at term with an unfavorable cervix.

-          Subjects received 200 mg mifipristone or placebo for the first 2 days with induction of labor by vaginal PG tablet or amniotomy with oxytocin infusion on day 4.

-          It was found that rate of spontaneous labor were higher, mean interval to onset of labor was shelter, bishop score better in mifipristone group compared with placebo group. However no significant difference was found in the rate of C.S. among the two groups.

-          No maternal / fetal side effects occurred from the drug.

-          Similar study in subjects with previous low transverse C.S. showed similar result with low rate of uterine rupture (21%) but study group was small (n=32).

Oxytocin

-          Oxytocin has been used for cervical ripening.

-          It was used before introduction of prostaglandins.

-          However it is laborious, requiring constant monitoring for up to 8-15 hours

-          Controlled studies carried out by Roberts (1988) have shown it to be a less satisfactory agent.

 Amniotomy

-          Amniotomy could result in vaginal delivery in most women with good cervical score.

-          According to an article on amniotomy to shorten spontaneous labor: Cochrane Library Issue 4 2002:

o       Amniotomy is known to reduce duration of labor by 60-120 minute

o       However it is associated with increased C.S. rate – O.R. 1.26

o       Significant association has been found between amniotomy and decrease use of oxytocin O.R. 0.79 confidence internal 95%

 Oxytocin and Amniotomy:

Amniotomy followed by oxytocin infusion has shown to decrease duration of labor

Proper evidence in this respect not available

 Extra Amniotic Foleys Catheter

-          According to randomized trials Foleys catheters are as efficient as prostaglandins and superior to placebo as regards change in bishop score and duration of labor. There was no difference in C.S. rates

-          Studies show that subjects with Foley’s catheter need oxytocin augmentation after balloon expulsion.

-          Mechanism of action:

A.    Direct pressure and over stretching of lower segment of uterus and cervix

B.     Local action of PGs,

 Membrane Stripping:

-          Causes a rise in PG concentration and increase in endocervical phospholipase A2

-          Elevation lasts for 2 hours followed by increase in uterine contractions for 3-4 hours

-          This might cause ripening of cervix and labor occurs in few days.

-          Several randomized studies have been done whose results are conflicting.

-          Several investigators found a rise in spontaneous labor within 3 to 7 days of production. 2 groups found decrease in induction role. 3 trials showed a decrease in post date rates. No significant difference in mode of delivery.

 Relaxin

-          Earlier studies show than 1-4 mg. of purified porcine relaxin accelerated rate of cervical change and reduced time of delivery.

-          According to randomized placebo controlled trial on 71 women use of relaxin improved cervical score, increase rate of spontaneous labor, decrease mean length of labor. C.S. rates were same in both groups.

Breast Stimulation

-          According to a study – intervention for improving outcome of delivery at or beyond term:

-          2 trials were done to show relation between nipple stimulation and induction of labor

-          Evidence show no decrease in post term pregnancy (or 0.52).

        Estrogens, hyaluronidase, corticosteroids. Castor oil bath and sexual intercourse have been studied in induction of labor but proper evidences to support them not available.

 INCREASING C.S. RATES

Definitions:

Total C.S. rate: (Total number of births by C.S. / Total number of Births) X 100

 Primary C.S. Rate:

It relates the number of first C.S. births to the total number of births to women who have not had a previous C.S..

Primary C.S. Rate: (Number of Primary C.S. Births / No. of primary C.S. births + No. of Vaginal births) X 100 

[Excluding V.B.A.C.s]

 V.B.A.C. Rate:

(Number of vaginal births after previous C.S. / No. of vaginal births after a previous C.S.) + No. of repeat C.S. births

[Elective Repeat C.S. + Indicated repeat C.S.].

The caesarian section rates have increased dramatically over post 25%.

US rates rose from 5.5% in 1970 to 21.2% in 1998.

Year                Rate (US)

1989                22.8

1999                22.7

1991                22.6

1992                22.3

1993                21.8

1994                21.2

1995                20.8

1996                20.8

1997                21.2

1998                21.2

1999                21.2

As a result of this increase much attention has been focused in increase maternal morbidity cost of procedure. In 1990 Department of Health and Human Services: goal to decrease C.S. rate 15/100 live births by year 2000 which has not been achieved

 C.S. rates at SSGH

90                                            11/100 live births

91                                            17.3/100 live births

92                                            21/100 live births

93                                            20.12/100 live births

94                                            19.2/100 live births

95                                            15.5/100 live births

96                                            18.3/100 live births

97                                            21.5/100 live births

98                                            21.19/100 live births

99                                            21.42/100 live births

2000                                        21.22 /100 live births

2001                                        21.39/100 live births

2002                                        26.17/100 live births

 C.S. rates

US                   22%

Canada                        22

Ireland             14.6

UK                  19

Australia          18.23%

 Strategies for reducing the number of Caesarean births

·         Training of clinicians in procedure such as ECV, vaginal breech delivery, use of forceps.

·         The use and appropriate interpretation of electronic fetal heart rate monitoring.

·         Increasing the use of amnioinfusion

·         24 hours anesthetic facilities should be available

·         Blood Banking

·         Neonatal intensive care

 6 Strategies to reduce C.S. rate

1.      Education and Peer review

2.      External evaluation of C.S. rate

3.      Public dissemination of C.S. rate

4.      Change in physician payment

5.      Change in hospital payment

6.      Medical malpractice reform

 

The effect of education and peer review has been demonstrated in several reports. But the implementation and assessment of other strategies has been limited.

 Expanded concepts:

1.      Prevent C.S. for failed induction of labor by avoiding unnecessary inductions.

2.      Avoid hospital admission for false labor pain.

3.      Manage pain more effectively to help woman tolerate labor.

4.      Educate woman to expect a trial of labor after prior C.S. and make this a normal practice.

5.      Enlist nursing input in labor support.

 


ACTIVE MANAGEMENT OF LABOR

 

Dystocia Definition:

It is defined as difficult labor

·         Often ascribed to failed induction, cephalopelvic disproportion and uterine inertia.

·         Most often the true abnormality is malposition, asynclitism, inadequate flexion which presents large diameters to maternal pelvis.

·         Dystocia is often the cause for increased C.S.

 

Active management of labor has been proposed as a strategy to reduce C.S. due to dystocia.

 Components of the active management of labor

Aim:

To counter the widespread view that 1st stage of labor was to be managed expectantly with interventions reserved for 2nd stage in the form of operative vaginal delivery.

It is used to decrease the negative aspects of prolonged nulliparous labor, and emphasized maternal expulsion of fetus rather than delivery by traction.

Inclusion Criteria

1.      Nulliparity

2.      Spontaneous labor

3.      Singleton fetus cephalic presentation at term

Exclusion Criteria

1.      Induction of labor (in some subjects)

2.      Multiparous women

3.      Vaginal birth after C.S.

Components

A.    Organized component

B.     Medical component

 

A. Organized component contains  

Ø      Decreased subject anxiety

Ø      Consistent, appropriate care of subject

Ø      Prenatal education classes

Ø      Intrapartum reassurance set realistic subject expectations

Ø      Constant attention of subject during labor with a uniform approach to labor management without respect to time of day.

B. Medical Component

1) Subjects encouraged not to come to the hospital until contractions are both regular        and painful.

2) Diagnosis of labor is not made on cervical dilatation but rather on quality of contraction in conjugation with at least one of the following:

Ø      Complete cervical effacement

Ø      Rupture of membrane

Ø      Bloody show

Ø      Rupture of membrane soon after the diagnosis of labor if they are intact.

Ø      Subjects regularly examined for progress of labor

If at any examination the subject fails to demonstrate dilation at a rate at 1 cm. /hr. or more in 1st stage

à Diagnosis of inadequate progress of labor

à Augmentation with oxytocin 6 mu/min

à Increase rate of 6 mu/minute every 15 minutes until a frequency at 7 contractions / 15 minute or a maximum infusion rate at 40 mu/minute is reached.

à  Subjects encouraged to begin pushing only after a strong urge to push develops.

à C.S. is performed for secondary arrests at dilation or decent only after the appropriate contraction frequency or maximum infusion of oxytocin reached was achieved.

à Intra uterine pressure measurement not used.

à Labor assessed by frequency of contraction rather than measured or calculated intensity.

 

Efficacy

            Data from National Maternity Hospital, Ireland demonstrated a rate of C.S. for all nulliparous subjects of 5.5% in 1980. Approx. one fourth of C.S. were performed for dystocia with only 0.13% for C.P.D. and the rest being for posterior position, inefficient labor or failed induction. With use of oxytocin in 40.6% of nulliparous subjects admitted in spontaneous labor, 63% delivered within 6 hours of admission and 98% within 12 hours.

            In the first randomized trial 700 nulliparous subjects with term, singleton pregnancy was randomized at diagnosis of labor to active management or to a more traditional labor management scheme. Compared with control group active management was associated with 26% reduction in C.S. (14.1 to 10.5%) primarily due to decrease in dystocia. No change in forceps usage was noted. Mean length of labor decreased by almost 2 hours and maternal infectious morbidity was reduced by 50%. Organizational features were not incorporated.

 

Thus, if at any given institution the C.S. rates are higher than 11.5% then applying principles of active management of labour will help in shortening the duration of labour, decreasing the infectious morbidities and increases the incidence of mothers delivering within 12 hours of active labour. It also overcomes the delay if any, associated with epidural analgesia.    

           

A troubling observation was higher incidence of C.S. in second stage of labor (2-4% versus 0-2%).

            Although epidural analgesia, negative station on admission, chorioamnionitis have been identified as risk factors for C.S., further research is necessary to elucidate reasons for higher rate of intervention in 2nd stage and to define methods effective in decreasing this rate.

 

Safety Concerns

            After the initial studies at National Maternity Hospital Dublin (1983) concerns regarding safety of active management program were made. This one year study reported high intrapartum fetal deaths and neonatal seizures. But it was found that study group was small and time duration less. So a 3 year statistics was obtained from Dublin Hospital which showed no significant difference in birth injuries, neonatal deaths seizures, admission to ICU with control groups.

Suggestion:  Active Management does not compromise perinatal outcome.

 

Rationale for the efficacy of active management:

            Active management at labor consists of multiple components. Many aspects at the programme contribute to any success that is achieved.

 

Elements of active Management at labor

1)         Diagnosis of labor: This is different in nulliparous (Likely to have effacement before rapid dilation) vis-à-vis multiparous subjects. This component discourages the diagnosis of labor until contractions are regular and painful and cervical effacement is complete because early diagnosis may lead to premature intervention like amniotomy or labor augmentation.

 

The following two interventions are less useful if they are done earlier but very useful if done timely:

  1. Amniotomy

            -           Shortens the active phase

            -           Shortens the labor by 2 hours without increasing C.S. rate.

      -           Decrease intrapartum risk of infection as the duration of labor is

                  shortened.

  1. Initial 1 mu/minute of oxytocin increased by 1 to 2 mu/minute at interval at an interval of 15 to 60 minute. Nowadays, 6 mu/minute is started and increased by 4 to 6 mu/ minute at every 15 minutes

 

            Also organizational component is important because it increases the success of labor. Prenatal education decreases subject anxiety and reinforces advocacy of vaginal birth. Constant companionship with emotional support during labor may influence outcome of labor positively.

 

 

W.H.O. Partogram:

            The basis of scientific study of progress of labor was developed by Freidman (1954) who described of graphically plotting the rate of cervical dilatation against time. The resulting graph becomes basis of modern partogram which now incorporates many relevant parameters related to labor, like condition of the mother and fetus in relation to each other chronologically on one page. These parameters include cervical effacement and dilatation, the descent of presenting part (in fifths of head palpable above the pelvic brim rather then station in an above or below ischial spies) the fetal heart rate, frequency and duration of uterine contractions, the color and quality of amniotic fluid passed per vaginum, maternal parameters such as temperature, pulse, blood pressure and drugs used.

The pictorial documentation of labor facilitates the early recognition of poor progress of labor. Plotting of cervical dilatation also helps in prediction of the time of onset of second stage of labor.      Rate of cervical dilatation has two phases, a show latent phase of labor during which cervix shortens from 3 cm to 0.5 cm and dilates to 3 cms. and a faster active phase when cervix dilates from 3cm to full dilatation.

            In order to identify parturients at risk of prolonged labor, a line of acceptable progress is drawn on the partogram. If the rate of cervical dilatation in any particular case crosses to the right of the line, progress is deemed unsatisfactory. The line of acceptable progress can be based on mean, median or slowest 10th percentile rate of cervical dilatation observed in women who progress deliver normally without intervention.

            In the presence of good contractions (at least > 2/10 minute each lasting > 40 sec.) the latent phase may last for upto 8 hours in nullipara and upto 6 hours in multipara. During the peak of active phase of labor cervix dilates at a rate approximately 1 cm / hr. in both nullipara and multipara. Multipara may dilate faster.

            Construction of normograms of expected normal progress or alert lines, with the addition of acceptable progress or action lines, prevents prolongation of labor being overlooked and is of considerable diagnostic and educational value.
 

V.B.A.C.

Candidates for V.B.A.C

Selection Criteria:

A.    One or two prior low – transverse caesarian deliveries.

B.     Clinically adequate pelvis.

C.     No other uterine scar, anomalies, or previous rupture.

D.    Subject consent

E.     A physician readily available throughout the labor who is capable of monitoring labor and performing an emergency C.S.

F.      Availability of anesthesia and personal for emergency C.S.

 

Absolute Contraindications:

A.    Prior classical uterine scar.

B.     T shaped uterine rupture

C.     Operative complications at the time of 1st abdominal delivery.

D.    Previous uterine surgery with entrance into uterine cavity

E.     C.P.D.

F.      Transfundal uterine surgery

G.    Medical or obstetric complication that precludes vaginal delivery.

 

Expanded Indicators:

1.      Vaginal delivery after two or more prior C.D.s

2.      An unknown uterine scar.

3.      A low vertical uterine scar.

4.      Twin gestation.

5.      Breech presentation

6.      Post term pregnancy

7.      Suspected macrosomia

 

Success rates:

            V.B.A.C. success rate was 60 to 80%

            To compare success rates is difficult because the number of women offered a labor trial; hospital settings and labor management differ. This yields a selection bias because candidates of perceived high risk for failure may have been excluded.

 

V.B.A.C. rate: (No. of V.B.A.C./ No. of women with prior C.S.) X 100

Success rate of trial of labor after C.D.: (No. of V.B.A.C. / No. of women who had trial of labor after C.D.) X 100

 

20000 subject with previous C.D. à Trial of labor from 1987-1994

Success rates à76% to 82% à Rate of uterine rupture 0.2 to 0.8%

 

6138 women who underwent a trial of labor = 3249

or elective repeat C.D. = 2889            out of these, 1962 = 60.4% delivered vaginally with rate of uterine rupture rate at 0.3%

 

Subject Preferences:

            Many factors influence a subject’s decision for or against a trial of labor. 2/3rd of women preferred a trial of labor rather than an elective repeat C.D. when interviewed in third trimester of pregnancy.

Factors positively influencing a trial of labor included,

·         White and Asian Ethnicity

·         Recovery time

·         Desire to experience vaginal birth

·         Fear of major surgery.

 

Factors that influenced selection of an elective repeat C.D.

·         Afro-American ethnicity

·         Pain of labor

·         Planned tubal ligation

·         Govt. hospitals

·         Schedule concerns

·         Perceived low chance of successive vaginal delivery.

 

Factors that yielded no preference

·         Maternal education

·         Perceived danger to mother or infant

·         Past experience with a vaginal delivery by a partner, family friend or family member.

 

Factors Influencing or Predicting Success Rates

            Some authors suggest that no clinical factors or confirmed methods can accurately predict a successful V.B.A.C.. However Rosen and Dickinson have analyzed the findings of 29 studies between 1982 and 1989 in a meta-analysis containing 8770 subjects that looked at association between the success of a trial of labor and various pre-existing conditions that could be used to predict a successful V.B.A.C..

Preexisting factors      C.P.D.

                                    Breech

                                    Used oxytocin

                                    Previous dilatation prior to C.S. could affect the outcome.

·         Women with C.S. for C.P.D. – lowest success. ODDS ratio 0.5 as per 24 studies and a 50% chance of success

·         Use of oxytocin – 10 studies

            Success V.B.A.C. less than those not receiving oxytocin (0.3)

·         Previous C.S. for Breech – successful trial twice likely.

·         Prior vaginal birth improves likely hood of successful V.B.A.C. in 11 of 12 studied or 2.1

As per Troyer and Parisi, certain obstetric parameters were identified in subjects with lower segment C.S. with a trial and scoring system was made. These were:

1)         Previous dysfunctional labor

2)         No prior vaginal delivery

3)         Non reassuring tracing on admission

4)         Labor induction

  • 91% of subjects with zero score (no risk factors) had successful trials.
  • 73.9% with 1 risk factor
  • 66.7% with 2
  • 46.1 with 3 or 4 factor

 

Turner: Previous vaginal delivery is most important factor in determining successful V.B.A.C..

Duff: in a study of 131 subjects found that subjects who have history of C.S. for causes other than dystocia there were increased chances of successful V.B.A.C..

 

Risks of Vaginal Birth after Caesarian delivery

 

The most severe complication resulting from a trial of labor is uterine rupture, which can be life threatening for the mother and infant. In several large series, the reported rate of uterine rupture with:

·         lower segment transverse incision is 0.5 to 1.5%

·         low vertical incision 1-7%

·         inverted T shaped incision 4-9%

·         classical uterine scar 4-9%

·

In most cases reason for rupture in a V.B.A.C. candidate is unknown and that poor outcomes can result even in appropriate candidates. Close observation and high index of suspicion for uterine rupture in women undergoing labor trials are necessary.

 

Maternal risks after V.B.A.C. compared to elective repeat C.S.

            According to a meta-analysis that included 31 studies with 417 trials of labor conducted by Rosen et al maternal febrile morbidity was greater in subjects with elective repeat C.S.. Uterine scar dehiscence or rupture was 2.8 times more in failed trial as against elective repeat C.S.

 

Flamn and Coworkers – in a Multi centric study compared outcomes of subjects who attempted trial with elective repeat C.S.

            Trial of labor – shorter hospital stay, decreased incidence of postpartum transfusion and decreased postpartum fever.

 

A study by McMahon on VBAC v/s elective C.S. showed:

            8.2% - maternal complication: similar in both groups

            1.3 Major Complications (hysterectomy, uterine rupture operative injury

            6.9 Minor (fever, BT, abdominal wound infection)

            Major Complications were 1.8 fold in trial group of which 92.5% were in trial group with failed trial.

 

Neonatal and Perinatal risks of V.B.A.C

            Overall perinatal mortality rate was 1.4% in women undergoing a trial of labor. The perinatal death rate was 2.1 times that among women undergoing an elective repeat C.D. (P< 0.001). When fetal deaths occurred before labor, fetuses weighing less than 750 gm, and those with congenital anomalies incompatible with life were excluded, there was no evidence of excess deaths among the trial of labor group (P=0.9). The perinatal mortality incidence was 9 per 1000 live births in trial of labor group and 5 per 1000 in the elective C.D. group (P=0.09)

            Majority of infants who delivered vaginally (about 97%) had 5 minute Apgar scores of 8 or more. Neonatal assessment can be subjective and Apgar scores may be influenced by gestational age, medications initiated during labor, presence of meconium or infection.     

Infants delivered by elective C.S. had an increased rate of transient tachypnoea of newborn compared to infants born vaginally after a trial of labor. Also, compared with a successful trial of labor, infants delivered abdominally after a failed trial of labor had more neonatal morbidity, increased rates of suspected or proven sepsis, and longer hospital stays. Neonatal outcomes after a successful trial of labor were similar to routine vaginal births. 

 

 

ROUTINE USE OF EPISIOTOMY IN MODERN OBSTRETICS

 

Indications:

1.     Nullipara with Rigid Perineum

2.     Shorten 2nd stage of labor for maternal causes

3.     Abnormal Presentation – Breech

4.     Operative Vaginal Delivery – Forceps

5.     Anticipated Shoulder Dystocia

5.

Midline versus medio-lateral:

 

Midline incision:         Carried out vertically inferiorly

Commonly used in US

            Easy to repair, less painful,

Mediolateral incision: Begin in midline but is directed laterally and downward away from

the rectum.

Commonly used in United Kingdom

Less chance of tear extending into the rectum

 

Coasts et al: prospective study on 407 primiparous subject receiving either medial or mediolateral episiotomy. Laceration of the anal sphincter and rectal mucosa was found in 11.6% medial episiotomy and in 2% mediolateral episiotomy

 

Episiotomy in prevention of severe perineal tears

 

            One of the major justifications for the use of episiotomy is the suggested protective role of episiotomy in prevention of occurrence of third degree and fourth degree lacerations. It was found that these injuries range from 0% to 2.3% in women with intact perenia, 0.2 to 0.9% in women with a mediolateral episiotomy, to 3% to 24% in women who underwent midline episiotomy.

            Benefits of episiotomy to prevent perineal lacerations, thus improving care providers an ability to repair them seems baseless. No evidence shows that first degree or second degree perineal tears cause long term consequences, No scientific evidence supports the claims that liberal episiotomy use reduces a subject’s risk for third degree laceration during birthing process. On the contrary, studies have consistently shown that routine episiotomy is associated with major perineal, anal sphincter and rectal tears even after controlling for confounding variables.

            .

            Various trials   concluded that the major risk for perineal damage was the performance of the episiotomy, with most perineal injuries caused by extension of the episiotomy. Rather than protect the perineum from damage, as derived, episiotomy contributes to damage. Anal sphincter damage was seen more commonly in subjects with episiotomy and 3rd degree and 4th degree lacerations seldom occurred without an antecedent episiotomy, though anterior tears were seen more commonly in selective episiotomy group.

            Although mediolateral episiotomies had a strong protective effect on occurrence of severe perineal lacerations, there is no justification for recommending more liberal use of the procedure. With large reduction in use of episiotomy there was an associated significant reduction in perineal trauma in all groups of women except for nulliparous women with macrosomic infants. Thus episiotomy use in spontaneous vaginal delivery is associated with increased perineal trauma and decrease in the rate resulted in more intact perineum. 

            The only negative outcome associated with decrease in the use of episiotomy was an increase in the rate of vaginal lacerations the consequences by which are of unknown significance. 

Episiotomy and Spontaneous tears: 

            One of common reason of performing episiotomy is to prevent spontaneous tears and as an accepted surgical dictum that a well defined surgical incision is easier to repair than ragged tear. 

Larson examined 2144 deliveries and episiotomy with spontaneous tears:

                                                                        Episiotomy group                    laceration

            Infection                                                         > 10%                                      2%

            Poor healing with disturbance in 1º healing    29%                                         9%           

According to Sleep et al: As compared episiotomy group required 100 more packets of suture material and 13 more hours of repair as compared to restrictive group. 

Prevention of pelvic relaxation:

  • Episiotomy prevents pelvic floor relaxation and ultimately cystocele and rectocele.
  • Episiotomy which involves only the more superficial levator ani muscles and musculocutaneous tissue cannot theoretically achieve this effect during child birth
  • Maternal expulsive efforts and compression of presenting part of fetus.
  • Pelvic floor stretches and distends
  • Functional and anatomical alterations in the anatomic and physiologic muscle, nerves, ligaments and viscera controlling continence and reproduction.
  • Liberal use of episiotomy has been shown to be associated with low frequency of anterior vaginal and labial tears.
  • Women with anterior vaginal and labial tears were found to have a higher incidence of cystocele.

Snook’s et al examined pelvic floor musculature and innervations in women in the antepartum and postpartum period. 36% subject developed SUI. These subjects had manometric and neurophysiologic evidence of weakness caused by denervation of pelvic floor musculature. This concept supports the thinking that cause of pelvic floor relaxation is pelvic neuropathy during child birth. 

Sleep et al found 19% of women in both the groups had urinary incontinence 3 months after delivery with 6% needing to wear protective pads. These findings were not different significantly among the restrictive and liberal episiotomy groups. The authors concluded that liberal use of episiotomy did not seem to prevent SUI. 

Rockner et al found 36% women had SUI who underwent mediolateral episiotomy compared with women who experienced spontaneous tears. The need for protective pads was higher in this group. 

To summarize the data reviewed no conclusive evidence supports the routine use of episiotomy to prevent pelvic floor muscle damage, subsequent pelvic relaxation, and its attendant complication of urinary incontinence fecal incontinence cystocele and rectocele. Data had shown weakened PFMS to be worse in women who had episiotomies compared with women with spontaneous tears. 

Prevention of Fetal Injury 

Another claimed benefit of episiotomy is the protection of fetus from injury, including IVH and fetal asphyxia. In addition episiotomy is recommended to prevent or decrease the risk for damage to fetus in case of fetal distress and shoulder dystocia. But now many studies have been done which found no correlation between incidence of IVH with intact perinea or episiotomies. No association has been found between fetal head compression and incidence of IVH in low birth weight infants questioning the belief that episiotomy prevents IVH.             Also no significant differences in Apgar scores have been found when episiotomy group was compared with lacerated group or non traumatic birth group. No difference in duration of second stage of labor in subjects with episiotomy compared with women with intact perinea. Thus no scientific claim seems to exist for beneficial effect of episiotomy and shortening 2nd stage, preventing fetal distress as measured by Apgar scores, cord blood gasses or admissions to NICU. 

Shoulder Dystocia and Episiotomy 

Common obstetric doctrine calls for use of generous episiotomy in subjects with suspected shoulder dystocia. No published data exists supporting its common use.

Nocon studied a shoulder dystocia patients. 16% had episiotomies. 22% of infants had injuries. 17 did not have episiotomies. 29% of infants had injuries. Difference is not statistically significant. 

Arguments which support avoidance of episiotomy in case of shoulder dystocia: 

  • Shoulder dystocia is a problem with fetal shoulder and bony pelvis and not soft tissue.
  • It is fetopelvic disproportion between soft or bony tissues of fetal shoulder and maternal bony pelvis.
  • It is not a fetoperineal dystocia thus; episiotomy should have no demonstrable beneficial effect.
  • Operative vaginal delivery:

Obstetricians are urged to use routine episiotomy in conjunction with operative deliveries. It is believed to minimize perineal trauma and prevent pelvic floor dysfunction. 

Coombs et al examined 2832 operative vaginal deliveries. 30% subjects had 3º/4º PT Attributable causes of these were

1) Midline episiotomy

2) Nulliparity

They suggest that mediolateral episiotomy for all operative vaginal deliveries might prevent 3º/4º lacerations but not all lacerations would be avoided. 

A retrospective cohort study, Helwig et al studied the association between midline episiotomy and 3º/4º laceration. They examined 392 deliveries. In 60% no episiotomy was performed. In 40% subjects’ episiotomy (midline) was performed. There was an increased rate of 3º/4º laceration. 

The concerns regarding the impact of episiotomies on perineal damage in operative deliveries need to be weighed carefully against the benefits of timely procedure. Unfortunately data are insufficient to make to make a definitive statement regarding the use of episiotomy at operative vaginal deliveries. 

Complications of Episiotomy:

 As with any surgical intervention, episiotomy presents risks. Extension, increased blood loss, postpartum pain and edema, dysparunia and infections are associated with episiotomy. Further complications exist in the form of wound infections or breakdown. 

Other commonly recognized complications of the procedure include haemetoma formation, recto-vaginal fistulas and abscess formation. Relatively rare problems include endometriosis in the episiotomy scar, non-healing of scar, lidocaine intoxication of the neonate and fetal injury. Even maternal deaths have been reported as a complication of episiotomy. 

Postpartum Hemorrhage and Haemetoma:

     Episiotomy is a bloody procedure regardless of technique used. Parturients undergoing the procedure suffer a greater blood loss than do those who deliver over an intact perineum. The blood loss could be upto 600 ml. which is much more than compared with subjects with spontaneous tears. Mediolateral episiotomy was the most important risk factor for PPH, midline episiotomy played a lesser, but significant role in the development of PPH though all types of lacerations were also associated with PPH. So avoidance of episiotomy may be one of the most powerful means to decrease excessive intrapartum blood loss. Haemetoma of perineum is reported with episiotomy. It may develop secondary to poor approximation of wound or failure to obliterate the soft tissue dead space, may subsequently become infected, ultimately erode the recto-vaginal septum causing recto-vaginal fistula.     Rectal wall may be perforated with scissors while performing episiotomy resulting in unrecognized lacerations in the recto-vaginal septum commonly described as buttonhole fistula (8/7500). 

Pain and Edema:

     Questionnaires from women found that women with spontaneous perineal lacerations experienced much less pain (15% p) compared to women who underwent episiotomy (37%). A total of 19% of women who underwent episiotomies complained of dysparunea. for 3 months postpartum compared with 11% in spontaneous laceration group. There was a greater incidence of pain when performing certain activities such as sitting, defecating, passing flatus and winding. Avoidance of routine episiotomy provided benefits in terms of decreasing perineal pain and improving sexual functioning. Episiotomies seem to be more uncomfortable for parturient in the immediate postpartum period then do spontaneous laceration, regardless of type of episiotomy. In terms of long term perineal pain no definitive date suggest that either entity causes more pain. Restriction of episiotomy seems to have little impact on dysparunea. 

Episiotomy infection and breakdown

     Infection of episiotomy or perineal region is not a common finding. Infectious process may include a stitch abscess, a wound infection or an abscess of perineum incidence being 0.35% to 10%. Infection and dehiscence of an episiotomy usually become apparent on the third or fourth day postpartum. Subjects may complain of pain and vulval edema and purulent discharge. Many factors predispose subjects to infected episiotomies including infected lochia, devitalized tissues, and fecal contamination of wound, overall poor hygiene and care of episiotomy wound. Although rare, perineal abscess, recto-vaginal fistula, complete dehiscence, necrotizing fascitis are most debilitating.  

CONTROVERSIES IN THE INTRAPARTUM MANAGEMENT OF TWIN GESTATIONS  

Controversies in the route of delivery:  

Indications of C.S. (Routinely recommended)

  • Conjoined twin
  • Placenta Previa
  • Monoamniotic twin
  • Certain congenital anomalies
  • Possible interlocking twins
  •            

     The optimal mode of delivery in other situations is controversial.

     For the purpose of intrapartum management, twins generally fall into one of three categories

1) Vertex – vertex                   42.5%

2) Vertex – non-vertex            38.4%

3) Non-vertex – other                         19.2%

Presentations of the fetuses must be established with intrapartum sonographic examination as 75% of subject undergo spontaneous version of at least one fetus at term.

Incidence of C.S. is lowest in vertex-vertex twin: 6.8% 

Internal pudalic version for transverse 2nd Twin:  

  • Incidence: 4.9 to 7.2%
  • Option for delivery :   C.S.
  •                                     ECV
  •                                     IPV

     In 1988 Rabinovici et al used internal pudalic version in 11 subjects. Mean gestational age : 36 to 40 wks. 1st vertex vaginal delivery, 2nd baby transverse lie with intact membranes. Epidural / GA (operator located and grasped feet of twin B through intact membrane. The feet are then pulled toward the birth canal while the other hand was used to dislodge and elevate the fetal head towards the fundus of the uterus. ARM was done only when the lie is longitudinal and breech presentation. This was performed in all 11 subjects and APGAR was normal 

     Chauhan et al. analyzed data of 11 series of vertex – non-vertex twin (n=638) delivered by IPV / assisted / breech extraction. 90% of twins had birth weight > 1500 gm. Complication rate was 1.4%, which included fracture clavicle, humerus. When birth weight was > 3 kg: Fetal distress, Cord prolapse, C.S. for failed extraction was more common.

 

In other study three groups of infants were compared.

1) Breech extracted 2nd born twin

2) Their siblings

3) Twin delivered by C.S. for malpresentation  

Conclusion:

  • No significant difference in morbidity except 2nd born twin delivered by C.S. had a greater incidence of respiratory distress syndrome than did their siblings (72:53: P = 0.05)
  • Breech extracted 2nd born twin had a significantly greater duration of mechanical ventilation and O2 therapy compared with vaginal A’s twin.
  • Above results were unchanged when data were reanalyzed to exclude infants weight was > 1500 gm.
  • C.S. did not improve outcome when breech extracted 2nd born twins were compared with 2nd born twin delivered abdominally.
  • Vaginal delivery was associated with an improved out come for vertex 1st born twin.
  • More data are needed on the safety of vaginally delivered, low birth weight, 2nd born twin before any concrete recommendations can be made.

Vertex-Non-vertex Twins: 

A major area of controversy in obstetric literature is the optimal management of vertex-non-vertex twin gestation. Issues contributing to this area of controversy include: 

  • Gestational age of the fetuses,
  • Difference in birth weight among the inter-twin pairs.
  • Experience of external cephalic version
  • Risk of performing total breech extractions.

     Earlier C.S. was recommended to improve neonatal outcome in all twins with one fetus in non-vertex presentation but now use of sonographic estimates of fetal weight and visualization of fetal lie combined with electronic fetal heart rate monitoring have made this approach questionable.

 135 sets of vertex-non-vertex twins were retrospectively reviewed.

            In 69%                        - breech extraction was performed on twin B

            9%                   - twin B was delivered as vertex after successful ECV

            22%                 - C.S. was performed on both twins.

At birth weights of > 1500 grams no low 5 minute Apgar scores, neonatal deaths or documented cases of IVH occurred whereas the incidence of these complications was significant in infants with birth weights of less than 1500 gms delivered by breech extraction.

 Recommendations for vaginal breech delivery of twin B following criteria are met:

  • Adequate Maternal Pelvis
  • Estimated fetal weight > 1500 g and < 3500 g.
  • Flexed fetal head
  • Sonographic estimates of fetal size
  • Use of sonography to facilitate breech extraction

         5 minute Apgar score and neonatal outcome variables in non-vertex twin B fetuses delivered abdominally versus those delivered vaginally for neonates > 1500 gm were compared. Apgar scores with weights between 1500 to 1999 gm showed a trend towards increase in low 5 min score. There were no deaths in either group; incidence of neonatal depression was similar. No difference in incidence of grade 3, grade 4 IVH or incidence of respiratory distress in vaginally delivered Twin B was found. Thus, all clinically significant neonatal morbidity was lightly associated with gestational age and birth weight but was not associated with the mode of delivery. Attempts at vaginally delivery of non vertex second twin weighing more than 1500 gms are safe. 

ECV in non-vertex 2nd twin: Now a days there is a consensus in favour of vaginal delivery for non-vertex. 2nd twin but controversy still exists whether ECV must be done or breech extraction be performed.

According to studies by Gocke-1989. 136 cases of twins with non-vertex 2nd twins were studied: 

  • derwent attempted ECV
  • 55 underwent attempted Breech extraction
  • 40 underwent attempted primary C.S.
  • Success rate of ECV was 46%
  • Breech extraction was 96%
  • C.S. rate in patients with ECV was 39%
  • Breech extraction 4%
  • 7 subjects underwent successful ECV but 1 required C.S..

The authors concluded that primary breech extraction of second non-vertex twin was a more reasonable alternative. 

As per studies by Chauhan S P (1994)

  • 44 successful outcomes of non-vertex twins were studied.
  • 23 delivered by total breech extraction
  • 21 delivered by attempted ECV
  • Vaginal delivery occurred more often in patients who underwent breech extraction.
  • The authors concluded that breech extraction was a better alternative in these cases.

Non-Vertex Twin A: 

In approximately 20% of twin pregnancies twin A presents during intrapartum period as non-vertex. Although, clearly, most of the controversy in obstetric literature has focused on non-vertex second born twin, questions remain regarding preferred mode of delivery of fetuses in this presentation. 

Possibilities for delivery include:

1.      Elective C.S.

2.      Vaginal breech delivery of twin A

3.      External cephalic version of twin A

3. Currently recommended and most commonly used route of delivery is abdominal. Concern over vaginal delivery of non vertex twin A primarily involves risks of fetal entanglement. (Overall incidence is 1 in 645 twin-births). Twin entanglement was more often encountered in breech vertex presentation (1 in 91) than other presentations (1 in 1982 P < 0.001). Kelsick and Hinkoff demonstrated an almost 2 fold i.e. (4.6% versus 2.4%) in perinatal mortality in first-born twins delivered vaginally versus by C.S.. Blickstein compared neonatal outcome of Twin A Breech and Twin B vertex that delivered vaginally (n=24) with those delivered abdominally (n=35). The perinatal outcome was similar in both groups. Specifically, incidence of birth asphyxia, neonatal jaundice, birth trauma and perinatal mortality was same in both groups.

 

          A prospective randomized controlled trial to determine optimal mode of delivery of non vertex twin A and twin B other presentation is recommended. Vaginal delivery of non vertex twin A is considered investigational and undertaken only if there are personnel present who are skilled in management of this type of delivery and adopt in maneuvers to decompress interlocking twins. 

Vaginal delivery may be considered in breech-breech and breech-transverse twin if estimated fetal weight (by intrapartum sonography) is between 1500 gm. and 3500 gms, fetal head is not hyper-extended, footling breech does not occur and pelvis is adequate. Breech delivery of non-vertex low birth weight twins is not advocated. 

Vaginal Versus Abdominal Delivery of Triplet Gestations: 

Over past 10-20 years, C.S. for triplets has become widely accepted. Arguments favoring C.S. includes lower morbidity and mortality as compared to vaginal delivery and need for less technical expertise. According to a study by Upitz improvement in neonatal outcome in patients delivered by C.S. was reported. 

Recently controversy regarding delivery of uncomplicated triplets was raised. No benefits in C.S. babies have been demonstrated. Recently studies in Netherlands compared perinatal morbidity and mortality between two hospitals. In C.S. group it was 18.4% whereas in vaginal group it was 7.8%. Optimal intrapartum management of uncomplicated triplet gestation is still controversial. 

Delayed delivery of second twin: 

     PPROM before 26 wks gestation occurs in 1.37% of twin gestations. In most cases labor ensues resulting in delivery of both twins. But in some cases after delivery of the first twin contractions subside. In that case a possibility of delayed delivery exists.  

    In one study of 21 subjects the management done included intravenous antibiotics in 17 of 21 subject, tocolytics in 11 of 21 subject, no cerclage was done. Age of 1st delivery was 24 wks with range of 17 to 29 weeks 5 days. The median number of days between the delivery of 1st and 2nd was 23. 

    In another study in 21 subjects cerclage was done. Median gestational age at 1st delivery was 21 weeks with a range of 16 to 32 weeks. Median number of days gained after placement of cerclage was 26 days with a range at 6 to 138 days. 

     In 1994, 8 sets of twins and 3 triplets were managed with I.V. Antibiotics + tocolysis + cerclage after delivery of first twin. Gestational age at first delivery was 15 to 23 wks.

Of these 11 subjects:   2 had successful outcome

                                    2 delivered at 35 to 38 weeks

                                    4 delivered at 24, 25, 27, 28 wks.

                                    5 delivered before age of viability.

 

Outcome is obviously better if the gestational age at 1st delivery is closer to viability. 

Contraindications of continuing such a pregnancy:

·         Gestational age < 21 wks

·         Evidence of amnionitis

·         Evidence of fetal compromise

·         Heavy vaginal bleeding s/o. Abruption

·         Monochorionicity 

Post-Dated Twins:

Prolonged pregnancy in singleton gestations is associated with increased perinatal morbidity and mortality, which is caused by progressive uteroplacental insufficiency with advancing gestational age. A pregnancy is defined prolonged or post term when it exceeds 42 wks. gestation. Whether it holds true for multiple gestations remains undetermined.             Studies show that intrauterine growth after 38 was gestation ceases altogether or increases minimally in twins. Also twins weighing > 3000 gms have higher mortality rates, increase incidence of low Apgar scores, respiratory disorders and seizures than their singleton counterparts. On comparing differences in placental grading at various gestational ages in twin and singletons Old et al found that there was an advanced sonographic maturation of twin placentae. Grade III were noted as early as 29 to 31 wks. in contrast to 39-40 wks. in singleton pregnancy.

Also L/S ratio of more than 2 was observed for twins at approx 31 to 32 wks. whereas this did not occur, just up to after 35-36 wks in singleton pregnancies. Accelerated maturation in twins may be complicated by hypertensive disease, IUGR or other factors. No evidence suggests that in uncomplicated twin maturation occurs earlier leading to an improved outcome for preterm twins.

Avg. length of gestation for twin pregnancy is 36.8 wks. as compared to 39.5 wks. in singletons and average birth wt. of 2380 gms. for twins as compared to 3249 gms. for singleton neonates. Lowest fetal death rate for twins has been shown to occur at 36-38 wks. gestation. There was no increase in low Apgar scores, Meconium stained liquor, C.S., birth injuries or other neonatal morbidities at at-least 38 wks. gestation.

Mono-amniotic twins:

  • Rare incidence / 1/10,000
  • Perinatal mortality: 30 to 70%
  • Primary risk factors: cord entanglement, fetal death
  • Optimal intrapartum management of monoamniotic twins in unclear. Optimal timing of delivery is also unclear. Some authors suggest delivery at 32 wks. Some believe that the low in utero mortality rate after 30 to 32 wks may not justify preterm deliveries.
  • Generally intrapartum management of monoamniotic twin is not controversial as most obstetricians usually do C.S. for the risk of cord entrapment.
  • Vaginal delivery may be done in: Normal fetal growth, normal umbilical artery
    CONSIDERATIONS FOR DELIVERY ON INFANTS WITH CONGENITAL ABNORMALITIES

Conditions placing fetuses at risk for intrapartum compromise: 

Neural Tube Defects:

         N.T.D. in particular meningomyelocele have long been the centre of controversy as to whether the route of delivery influences the outcome. Theoretically concerns exist that exposed neural tissue during labor and a vaginal delivery may be further damaged by mechanical forces of labor and by amniotic fluid contamination of C.S.F.  

A prospective series by Healthy et al compared infants with spina bifida delivered by C.S. before labor, C.S. after labor and vaginal delivery. Levels of motor deficit was assessed for each child as their motor level in relation to their radiological determined anatomic level with degree of deficit and then evaluated across delivery categories. A significantly greater degree of motor loss, regardless of anatomic level of lesion was noted in children delivered after labor either by C.S. or vaginally. Greatest preservation of motor skills was noted in children delivered by C.S. before onset of labor. Follow up retained original significance.           

     Another study did not reveal significant differences among routes of delivery for N.T.D.. Also, although vaginal delivery initially seemed to be more neurologically deleterious to breech infants, even this significance was lost on follow up. Eventually it was found that ambulation was more impaired in breech delivered infants regardless of route of delivery.  

Studies for the route of delivery remains confounded by issues surrounding the varied manifestations of N.T.D., impact of optimal neonatal care, time of repair, contribution of breech presentation and postnatal complications including cord tethering. Counseling should include that route of delivery is only one contributory factor to eventual outcome. (and its effect seems to be relevant to motor function alone). 

Abdominal Wall Defects: 

     Debate likewise continues for route of delivery in these conditions. Speculation continues regarding damage to the exposed abdominal viscera from acidemia, rupture and infection. Although initial trend existed to offer C.S., it is now reserved for mothers of infants with extra-corporeal liver involvement. Although numbers were small, even when cases of bowel dilatation were analyzed within each route of delivery, a significant advantage to a particular mode of delivery did not seem to exist. 

Congenital conditions not presenting increased intrapartum risk: 

  • Congenital anomalies like cardiac anomalies
  • Congenital diaphragmatic hernia
  • Hydrocephalus without macrocephaly
  • Posterior cystic hygroma

This entire group of fetuses is well protected during labor and delivery. A vaginal delivery should be anticipated with C.S. reserved for the usual obstetric indications. 

Condition with theorized but unstudied intrapartum risks: 

     For rare congenital anomalies, theorized risk for further damage during vaginal delivery exists. Included in this category are non-lethal skeletal dysplasias specifically osteogenesis imperfecta; achondroplasia, congenital contractures, massive intra-abdominal cystic lesions such as ovarian cysts and renal masses. In case of skeletal abnormalities there is an increased chance of fractures and dislocations during vaginal delivery. In many instances however C.S. is not entirely atraumatic and fractures can occur even with judicious care at elective abdominal delivery. In settings of anomalies involving vascular or cystic structures intrapartum rupture is likely. But some protection is afforded by intra-abdominal or thoracic placement of these structures. 

Conditions precluding vaginal delivery on an obstructive basis:     Caesarian section for subjects with congenital anomalies is often considered when the existing lesion presents a significant risk to the fetus or mother undergoing an obstructed labor. Classically, this has included infants with macrocephaly caused by severe hydrocephalus or massive intra-abdominal masses with enlarged girth and extrinsic lesions. Often teratomas, which significantly distort the normal fetal anatomy so as to impede descent of the fetus in the pelvic canal, can cause obstructions. 

Cephalo-pelvic disproportion:

     Severe hydrocephalus with macrocephaly presents significant C.P.D. risk for infants with BPD of more than 10 cm. Delivery by elective C.S. should be entertained. Even at C.S. at term, often represents a diameter that does not allow the infant to be safely delivered through a low transverse incision. Careful uterine incision extension, controlled low vertical or even classical incision despite the need for abdominal deliveries may be required when factors of maternal trauma from extensions and difficult extraction of macro-cephalic breech presentation are considered. 

     Cephalocentesis for the decompression of fetal head should be considered when severe hydrocephalus occurs in conjunction with other life threatening congenital anomalies such as holoprosencephaly, thanotophoric dysplasia. Delivery by C.S. would not be anticipated to alter these infants significantly compromised chances for repair and survival. 

     In contrast, when hydrocephalus is encountered as an isolated occurrence sonographic evaluation in form of cortical thickness is required USG is of little assistance in assessing eventual outcome including mortality and eventual developmental outcome. Route of delivery should be assessed based on relative macrocephaly with vaginal delivery tolerated without unduly harming the macrocephaly. 

     Masses of fetal head and neck such as teratomas and goiter may result in hyperextension of fetal head. In this setting C.S. is advantageous not only because of malpresentation secondary to hyperextension but also to optimize neonatal airway management. Coordinated care by perinatologist, neonatologist and a pediatric surgeon is often needed to secure the airway.

 

Shoulder or Abdominal Dystocia:

     Anomalies of the exterior neck or axilla also referred to, as late onset cystic hygromas are sometimes associated with an abnormal fetal position in labor. Infants having hygromas in the rage of 6 x 8 cms with an axilla, anterior neck or abdominal wall location have undergone vaginal delivery without significant obstruction of labor or damage to cystic mass. Larger lesions (15 x 20 cm. in axilla) are reported. Individualization with C.S. in these settings is recommended to avoid birth trauma. Because a rapid growth is characteristic of these lesions USG assessment at the time of delivery with regard to final decision regarding route of delivery is advisable. Favorable outcome following resection can be anticipated. 

     Extensive, ascitis alone or in conjunction with severe hydrops formation may preclude vaginal delivery because of abdominal dystocia. Fetal paracentesis before delivery by any route is advocated to optimize neonatal resuscitation by optimizing diaphragmatic movement. Abdominal fluid usually re-accumulates within a relatively short period of time (often within 24 hours). These approaches to drainage are thus warranted only when timing of vaginal delivery can be anticipated. 

     Congenital ovarian cysts are common intra abdominal cystic masses in female fetuses. Close surveillance and assessment at time of delivery is recommended because spontaneous resolution and marked enlargement both have been noted. Cystic masses are compressed without difficulty during pelvic delivery without undue risk for rupture. However, if a significantly enlarged abdominal girth is present to suspect dystocia, C.S. should be considered. 

     Renal mass i.e. congenital mesoblastic nephroma presents with polyhydramnios needs USG and at time of delivery for determination for the possibility of dystocia.  

     Regardless of location, teratomas present with a relative degree of dispute. Sacrococcygeal teratomas may vary in size, present with a breech; often need indicated preterm delivery for complications. They are best served by C.S., which avoids undue traction to avoid tumor, rupture or hemorrhage.

Timing of Delivery:

     Fetal congenital anomaly is a recognized risk factor for premature labor. Mostly conditions associated with polyhydramnios resulting from obstructive lesions of GIT or with impaired swallowing on a neurological or structural basis represent highest risk of preterm delivery. Since infants undergoing operative intervention during neonatal period are optimally managed as term infants, attempts should be made to halt preterm labor with tocolytic agents or taking action to decrease amniotic fluid volume. Therapeutic amniocentesis and indomethacin can be used. In rare conditions where prolongation of pregnancy causes detrimental changes, a preterm delivery is indicated e.g. gastroschsis.

Previously it was thought that subjects with hydrocephalus should be delivered at 36 weeks when lung maturity is attained. This was based on evidence that prolonged compression of cerebral cortex was detrimental to the neurological development of the fetus.

 Site of Delivery: 

     Optimizing the repair of congenital malformations is most often sited as the primary advantage for delivery of affected infants in a referral center. For some malformations, several series have advocated that with prenatal diagnosis and initial appropriate stabilization, subsequent transport of infants to the tertiary center provides usually advantageous outcome. Abdominal wall defects, congenital cardiac defects, and CNS lesions all these are included in trial category. 

     In cardiac defects data show that it failed to identify benefit to delivery of infant with congenital cardiac anomalies at tertiary care centres. Recent analysis of cardiac malformations repaired as either biventricle or univertricle revealed a greater survivorship only for referral hospital delivered infants undergoing biventicular repairs.

For infants with univentricular repairs, primary hypoplastic hearts eventual survival was statistically unchanged whether infants were delivered and transported or primary delivered and repaired at referral site. 

     For other anomalies, however when managed optimally by initial stabilization and repair delayed until after 1st 24 hours of initial resuscitation efforts are after often a complexity. These are best suited for referral hospitals. These include congenital diaphragmatic hernia.

      Other malformations pose such a neonatal emergency that delivery and resuscitation with subsequent transportation is precluded.

      Assessment of infants with congenital anomaly requires several services - clinical genetics, specialized diagnostic modalities. Ideally parents receive full information of possible interventions and outcome, for their infants before time of delivery.

 Delivery of Non viable Infants:

     Few disorders can be characterized as incompatible with life. Typically anencephaly, bilateral renal agenesis (Butler’s syndrome) and classic lethal trisomies 13 and 18 are associated with fetal damage within first days or weeks of life. Delivery by C.S. is not expected to affect this grim prognosis or provide benefit to infants affected by these conditions.

 
     

 
         
     

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