By Serena Gordon
In the hands of an experienced obstetrician, there are no differences in serious adverse events for babies or their mothers, the study found.
"Studies have suggested that maybe cesarean delivery is the best way, but there's no evidence to support the swing to cesarean birth. Perhaps the perception is that it's better for the baby," explained the study's lead author, Dr. Jon Barrett, chief of maternal-fetal medicine at Sunnybrook Health Sciences Center in Toronto, Canada.
Twins account for about 33 of every 1,000 births in the United States, according to the U.S. Centers for Disease Control and Prevention. The number of twin pregnancies has risen dramatically since the 1980s and 1990s because of assisted reproductive technologies.
The rate of cesarean delivery of twins has also increased, according to the study, published in the Oct. 3 issue of the New England Journal of Medicine. And Barrett said the "pendulum has swung too far to cesarean and now we may not have enough skilled practitioners to do these more difficult vaginal births."
To find out if cesarean birth offered any advantages over a planned vaginal delivery, Barrett and his colleagues recruited about 2,800 pregnant women from 25 countries. All were between 32 weeks and 38 weeks 6 days of gestation.
Elective delivery was planned between 37 weeks 5 days and 38 weeks 6 days of gestation. The babies were estimated to be at a healthy weight for their gestational age, and the first twin was in the head down position, which makes for an easier delivery.
About half of the women were scheduled to deliver vaginally, and the other half were scheduled for a cesarean-section. The women and babies were followed for 28 days after the birth to monitor for serious adverse outcomes, such as death or a serious problem with the baby, including spinal cord injury or signs of lung problems, according to the study. The researchers also looked for serious adverse events in the mothers.
The rate of cesarean delivery was 91 percent in the planned cesarean group. (Some women didn't complete the study.) For women assigned to the planned vaginal delivery group, 56.2 percent delivered both twins vaginally, and 4.2 percent had a combined vaginal-cesarean delivery. Forty percent of those planning a vaginal birth ended up having a cesarean-section, according to the report.
No difference was noted in the rate of serious adverse outcomes for babies or mothers between the two groups, the study authors noted.
The author of an accompanying journal editorial said mothers-to-be should be reassured by the findings. "This study found that a plan to deliver by cesarean or vaginally will yield a roughly equivalent result. It's a good study that should reassure women who want a vaginal delivery and their obstetricians that it's a reasonable and safe option," said Dr. Michael Greene, director of obstetrics at Massachusetts General Hospital in Boston.
However, Greene doesn't feel that this study will lead to a change in clinical practice, at least not in the United States.
"Obstetricians in the U.S. have resorted to more and more cesarean deliveries for circumstances that they see as a risk to the fetus," Greene explained. He added that breech births, where the baby is positioned for delivery with either buttocks or feet first, instead of head first, have all but disappeared in births of single babies.
"Almost half of the pregnancies in this study ended up being delivered by cesarean anyway. Presumably, there was an undue risk associated with carrying out vaginal delivery of the twins. Doctors have to use their best judgment," noted Greene.
Barrett and Greene said that women carrying twins who want to try to deliver vaginally need to make sure their obstetrician is experienced in delivering twins vaginally.
"Realize that you have a choice, and find a center or an obstetrician who is willing to [honor] your choice. If they can't offer vaginal delivery in their hospital, they should refer you to a center that can, rather than just diverting you to a cesarean delivery," said Barrett.