Route of delivery for the breech presentation: a conundrum

Our purpose was to determine the feasibility of resolving the controversy regarding route of delivery for breech presentation in a randomized, prospective fashion.

The National Institute of Child Health and Human Development-sponsored Maternal-Fetal Medicine Units Network, which is composed of 11 perinatal centers, was surveyed to determine the feasibility of a randomized clinical trial of cesarean section versus trial of labor for breech presentation. A review of the literature was performed to determine the experience of other investigators with designing and conducting an adequate prospective, randomized trial.

Principal investigators and faculty from seven of 11 centers within the Maternal-Fetal Medicine Units Network agreed to participate adn felt that they could adequately recruit patients for a trial in very-low-birth-weight infants. This would provide approximately 200 very-low-birth-weight fetuses in a breech presentation per year. Sample size calculations indicated that 1700 infants would be required. Investigators also had strong reservations about performing a trial of vaginal breech delivery for other gestational ages. A review of the literature indicates that other authors have encountered difficulty in attempting randomized clinical trials of this nature.

The Maternal-Fetal Medicine Units Network with its pool of 60,000 deliveries per year agreed that a randomized, controlled delivery route of labor in the 24- to 28-week breech presentation was not feasible in a reasonable period of time. A randomized clinical trial of larger fetuses in a breech presentation was also considered extremely difficult. These findings are similar to those of other authors who have attempted or proposed randomized clinical trials to determine the safety of planned vaginal delivery of the breech presentation at various gestational ages.