Women expecting twins now have good reason to explore the option of vaginal birth, according to a study published in the Oct. 3 online New England Journal of Medicine (NEJM).
An international study – the Twin Birth Study – involving 2,804 women in 106 hospitals in 25 countries, including eight hospitals in the U.S., showed that carefully selected mothers and babies do equally as well whether they and their physicians planned for a cesarean section or vaginal delivery.
To participate in the study, the women had to be between 32 weeks and 38 weeks and 6 days gestation. Their babies had to be at a healthy weight for their gestational age, and the first twin had to be in a head-down position.
The study group was randomly divided, with 1,392 women assigned to plan to have a C-section, and 1,406 assigned to plan to have a vaginal delivery, though they could switch to a C-section for one or both babies if medically necessary.
During the study, women in the cesarean group were better able to stick to their original plan: 90 percent delivered both their twins by C-section. The remaining 10 percent delivered one or both of their twins vaginally. Of the vaginal-delivery group, 56 percent delivered both babies vaginally, 40 percent had to have C-sections, and 4 percent delivered one baby each way.
The women and their babies were followed for 28 days following delivery to monitor any serious problems, including birth injuries, infection, deaths of mothers or babies, or signs of lung problems in the infants.
The findings showed that the risk of problems was the same for mothers and babies in both groups. About 2 percent of the babies and 7 percent to 8 percent of the mothers in each group had serious complications or died.
The study authors, led by Jon Barrett, MD, an associate scientist at the Sunnybrook Health Sciences Center in Toronto, noted that vaginal delivery for twins should only be considered under the same conditions described in their clinical trial. In addition, they said women should be attended by an experienced obstetrician and deliver in facilities that could perform an emergency C-section with 30 minutes if necessary.
In an editorial accompanying the original article, Michael Greene, MD, chief of the Massachusetts General Division of Obstetrics in Boston and an associate editor of the NEJM, issued a similar caution.
“These results do not indicate that all sets of twins should be delivered vaginally,” wrote Greene.
“Obstetricians exercising their best judgment delivered both twins by cesarean section in nearly 40 percent of the women assigned to planned vaginal delivery, which undoubtedly contributed to the salutary outcomes. However, the results of this study suggest that a plan to deliver appropriately selected sets of twins vaginally is a reasonably safe choice in skilled hands,” added Greene.
But there's the rub.
Because the rate of cesarean delivery of twins has increased in the U.S., the authors expressed concern that not enough doctors have the skills to handle breech births – it is not uncommon for second-born twins to enter the birth canal bottom first – or to perform more complicated vaginal deliveries.
The “pendulum has swung too far to cesarean and now we may not have enough skilled practitioners to do these more difficult vaginal births,” Barrett told HealthDay.
Because of this potential lack of skills and patient preference for C-sections to deliver twins, Greene noted in his editorial that “it seems unlikely that we will see a major change in use of cesarean delivery for twins nationwide.”