Safely delivering monoamniotic monochorionic twins

New research findings from investigators at the Cooper Medical School of Rowan University, Camden, NJ, have shown that vaginal delivery appears to be safe in monamniotic monochorionic (MoMo) twins who are appropriately identified. Dr. Meena Khandelwal et al. note that while theoretical risks are the basis for current practice and recommendations, their study offers important data on vaginal delivery as an option for MoMo twins.

As Dr. Khandelwal, Professor of Obstetrics and Gynecology at Cooper, explains: “Monoamniotic monochorionic twin gestations can be safely delivered by vaginal route with a similar success rate as in other forms of twin pregnancies.” She adds, “The improved outcomes for these pregnancies may not be due to route of delivery but due to aggressive monitoring of these pregnancies and improved medical care.”

The investigators’ award-winning paper on this research presented at the American College of Obstetricians and Gynecologists (ACOG) 2016 annual meeting quotes as a prelude to their study findings the current ACOG 2014 technical bulletin #144 instruction on this subject. The bulletin advises that women with MoMo twin gestations should have a cesarean delivery so as not to have “an umbilical cord complication of the nonpresenting twin at the time of the initial twin’s delivery.”

In this light, the researchers undertook a retrospective cohort study to ascertain whether vaginal delivery was feasible for these pregnancies. They reviewed all viable MoMo twin pregnancies beyond 24 weeks’ gestation that had been delivered in 2 tertiary-care centers over the last 15 years, comparing neonatal outcomes after planned cesarean delivery or attempted vaginal delivery.

Fifteen of 29 women with MoMo twins had a planned cesarean delivery, while the other 14 women attempted a vaginal delivery. Six of the latter 14 women had an induction of labor, but overall for the vaginal delivery group, 10 were successful in delivering both neonates vaginally within a median interval of 3 minutes between them. Cesarean delivery was needed for 3 women because of a nonreassuring fetal tracing, and 1 woman required delivery by cesarean for her second twin.

Significantly, the incidence of intracranial hemorrhage was lower in the neonates delivered vaginally versus those delivered via cesarean (0 vs 8, P=.006), even though gestational age at delivery (33.3 weeks vs 32.7 weeks, P=.5) and rate of fetal loss (1/14 vs 2/15, P=NS) were very similar. Further, for those delivered vaginally, respiratory complications and neonatal length of stay (18 vs 25, P=.09) trended lower than for those neonates delivered via cesarean. In 28 of all 29 pregnancies, entangled umbilical cords were observed at birth.

The researchers comment that women who have had a prior cesarean delivery chose repeat cesarean delivery more often. Also, both groups of patients had similar composite maternal outcomes.

As to the demonstrated success of a vaginal delivery in some study patients despite conventional wisdom, Dr. Khandelwal comments that “ACOG guidelines are used as ‘standard of care’ by most practitioners; so it is important that they discourage ‘expert opinion’ statements in their guidelines and encourage evidence-based medicine.”