Twin births today are different than when I arrived as half of a pair. Arriving as Twin A, I made a vaginal entrance head first as did my womb mate/brother, Twin B. Such an arrival was not unexpected because duo debuts are a natural event occurring every generation in my family, but my parents weren’t expecting this pair. Today’s twins differ from us because such births happen more frequently thanks to fertility treatments, many mothers are older and the arrivals are more closely scrutinized. Twin birth is associated with a higher risk of adverse perinatal outcomes than is a singleton birth.
Twin birth was the focus of a randomized clinical trial published this week in NEJM comparing the risk of fetal/neonatal death or serious neonatal morbidity in deliveries via a planned cesarean or planned vaginal delivery. Dr. Barrett and his co-authors studied the outcomes of 2804 women who delivered at 106 centers in 25 countries. Women were randomized to a delivery group after confirmation that the first twin was in a cephalic presentation. (Other fetal positions are associated with higher complication rates). They found that the delivery method did not significantly decrease or increase the risks of death or morbidity during the first 27 days of life.
Overall 2.2% of 1398 women with planned cesarean deliveries experienced an adverse outcome, compared to 1.9% of the 1406 women with planned vaginal deliveries. Maternal mortality and morbidity likewise did not significantly differ between the groups; the frequency of adverse outcomes was 7.3% for planned cesarean deliveries and 8.5% for planned vaginal deliveries. Most of the births (82%) were before 37 weeks, which is considered term gestation. In the planned cesarean group, 89.95 of the deliveries were by cesarean for both twins. In the planned vaginal delivery group, 56.2% delivered both babies vaginally, and 36.9% delivered both babies by cesarean.
In an accompanying editorial, NEJM Associate Editor Dr. Michael Greene noted that most prior evidence about the safety of twin deliveries has come from observational cohort studies. Those studies found planned vaginal deliveries (compared to a planned cesarean section) to be associated with poorer outcomes, especially for the second fetus in a non vertex position. He wrote that the study “does suggest that a plan to deliver appropriately selected sets of twins is a reasonably safe choice in skilled hands.” He noted that participating centers were required to meet appropriate standards to perform timely emergent cesarean deliveries.
My own entry went fine, but this study provides data indicating that vaginal delivery is a reasonable approach to plan in many twin pregnancies.
For more on this study, view the NEJM Quick Take, an animated overview narrated by our Editor-in-Chief, Dr. Jeffrey Drazen.