Major Finding: Women randomized to early or late external cephalic version had nonsignificant differences in cesarean section rate (52% vs. 56%), with a trend toward more preterm deliveries in the early-version group.
Data Source: A study that randomized 1,532 women with breech presentations to either an early external cephalic version or a later version performed at 37 weeks.
Disclosures: Dr. Carson said he had no relevant disclosures. The trial was funded by the Canadian Institutes of Health Research.
MONTREAL — Early external cephalic version increases the likelihood of cephalic presentation at birth, but does not result in fewer cesarean sections compared with later cephalic version, based on the results of an international, multicenter, randomized controlled trial.
In addition, there was a trend toward greater risk of preterm birth when the procedure was done early, defined as between the 34th and 35th weeks, reported Dr. George Carson, one of the investigators on the Early External Cephalic Version 2 (ECV2) Trial.
“This is actually very disappointing,” he said in an interview at the meeting.
“It is worth trying to investigate why turning the baby didn't result in a reduction in cesarean sections. Obviously the purpose of this was not to turn the baby – it was to reduce cesarean sections – and that didn't happen, and that's disappointing.”
The study randomized 1,532 women with breech presentations to either an early version or a later version performed at 37 weeks. The primary end point was the rate of cesarean section, with a secondary end point of preterm birth.
“The concern was that in performing version one might precipitate preterm birth, and so this could be the adverse effect of the attempt to turn the baby,” noted Dr. Carson, director of maternal-fetal medicine at Regina (Sask.) General Hospital.
Baseline characteristics including parity, types of breech presentation, and anterior placenta were similar in both groups.
Cephalic presentation at the time of delivery, due to either successful external version or spontaneous version, was higher in the early-version group (59% vs. 51%), and the difference reached statistical significance, said Dr. Carson. However, there was not a statistically significant difference in the cesarean section rate: 52% in the early group and 56% in the late group.
“More women delivered vaginally than was anticipated in the delayed group – due to spontaneous conversion and a small number of women who decided to deliver vaginally even though their baby was still breech,” he said, adding that overall, the cesarean section rate was high.
“Very few of these were done for nonreassuring monitoring. They were done in places that do a lot of sections anyway, so being cephalic was not in any way a guarantee that one wouldn't have a section done,” he said.
The increased rate of preterm delivery in the early-version group (6.5% vs. 4.4% in the late group) was not statistically significant, but it strengthens the argument against attempting an early cephalic version, said Dr. Carson.
“What I tell the women that I am trying to do a version on is, if we don't do it … they've got about a 70% chance of a cesarean section. If we do it, that could be reduced to about 50%. But my chance of getting the fetus around is only about 50%.
“And if we push hard on the uterus, maybe we could make them deliver prematurely. It won't be very premature, but it's still better to be term than 35 weeks,” he said.