Laird Harrison

February 15, 2013

SAN FRANCISCO, California — A planned cesarean delivery does not improve outcomes for most mothers of twins or their babies, researchers report here at the Society for Maternal-Fetal Medicine (SMFM) 33rd Annual Meeting.

"Planned cesarean section did not decrease or increase the risk of perinatal or neonatal morbidity for twins born at 32 to 38 weeks," said lead researcher Jon Barrett, MD, who is chief of maternal fetal medicine at the University of Toronto in Ontario, Canada.

For their large prospective randomized trial, Dr. Barrett and his team collected data from 106 centers in 26 countries. They compared outcomes between planned vaginal and planned cesarean deliveries.

Women pregnant with twins at 32 to 38 weeks of gestational age — with the first twin situated head first — were eligible for the study. Women were excluded if there was fetal reduction at more than 13 weeks of gestational age, a lethal fetal anomaly, or a contraindication to labor.

The researchers found no significant differences between the 2 groups.

Table. Outcomes of Planned Cesarean and Vaginal Deliveries

Outcome Planned Cesarean
(n = 2781)
Planned Vaginal
(n = 2782)
P Value
Death or severe neonatal morbidity 2.05% 1.87% .6569
Delivery of at least 1 child 89.9% 60.45% Not presented

The 2 groups were not statistically different in the gestational age of the fetus at randomization, the mother's age, the presentation of twin B, chorionicity, or the country's perinatal mortality rate.

The researchers did find that twin B was more likely to die or be born with a serious morbidity (odds ratio, 1.895; confidence interval, 1.329 to 2.703; = .0003).

Women who planned a cesarean delivery delivered earlier, and 89.9% delivered both babies that way.

Of those who planned a vaginal delivery, 60.45% delivered at least twin A that way. After the vaginal birth of twin A, the birth of twin B was a cesarean delivery in 4% of mothers.

This is a wake-up call to train obstetricians of the next generation that the best way to deliver twins is vaginally.

In the discussion after Dr. Barrett's presentation, a member of the audience cited a survey finding that many obstetrical residents are likely to recommend that mothers carrying twins undergo cesarean delivery.

"For obstetricians of our generation, this is a wake-up call to train obstetricians of the next generation that the best way to deliver twins is vaginally," said Dr. Barrett.

In response to another question, Dr. Barrett explained that the researchers did not stratify their results by body mass index.

This study makes an important contribution to the data on when cesarean deliveries should be used, said Michael Lu, MD, director of the US Maternal and Child Health Bureau, who was asked by Medscape Medical News to comment on the study.

"It is a well-designed study," Dr. Lu noted. "It serves to remind us that women with twins should be given the option of either vaginal birth or cesarean section. And vaginal birth, according to this study, does not appear to increase risks to either the mom or the baby," he explained.

The investigators and Dr. Lu have disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 33rd Annual Meeting: Abstract 7. Presented February 14, 2013.