Should breech babies be delivered vaginally or by planned cesarean delivery?

BACKGROUND: Some clinicians recommend cesarean delivery for all babies with breech presentation, while others encourage a trial of vaginal delivery for selected women. This randomized trial compared planned cesarean delivery (PCD) with planned vaginal delivery (PVD) for term breech babies.

POPULATION STUDIED: A total of 2088 women from 121 centers in 26 different countries were enrolled. Each woman had an uncomplicated complete or frank breech at more than 37 weeks’ gestation. Most of the women were aged younger than 30 years; approximately 50% were primiparous. Ultrasound sizing was performed on 40%, and external cephalic version was attempted in 20%. Fifty percent of the countries had a low perinatal mortality rate. Thus, the clinical setting is probably similar to that of family physicians in the United States.

STUDY DESIGN AND VALIDITY: This was a well-designed study. Participating subjects were randomly assigned (masked allocation) to either PCD (n=1043) or to PVD by an accoucheur experienced in breech delivery (n=1045). The accoucheur’s experience was confirmed by the department head, and approximately 60% had more than 10 years’ vaginal breech delivery experience. For those women assigned to vaginal delivery, a standardized labor protocol was used and was comparable with practice in the United States. The method of delivery was by assisted or spontaneous breech delivery with control of the after-coming head either by use of a forceps or the Mauriceau-Smellie-Veit maneuver. Cesarean deliveries were scheduled for women with gestation greater than 38 weeks. The follow-up rate was 99.8%. Analysis was by intention to treat, with lethal congenital anomalies excluded. Multiple logistic regression was used to assess for interaction; the Fisher exact test and the Wilcoxon rank-sum test were used to test outcomes, with a one-sided P value used for neonatal outcomes and a two-sided P value for maternal outcomes.

OUTCOMES MEASURED: The main outcome was perinatal or neonatal mortality and serious neonatal morbidity, including birth injury, seizures, and an APGAR score less than 4 at 5 minutes. A secondary outcome was maternal mortality or serious maternal morbidity in the first 6 weeks; cesarean delivery itself was not included as maternal morbidity.

RESULTS: At enrollment the groups were similar. Because of early results showing an important difference in outcomes, the trial was stopped early. In the PCD group, 10% delivered vaginally compared with 57% of the PVD group. Perinatal and neonatal mortality was lower in the PCD group than in the PVD group (0.3% vs 1.3%; relative risk [RR]=0.23; 95% confidence interval [CI], 0.07-0.81; number needed to treat [NNT]=100) as was serious neonatal morbidity (1.4% vs 3.8%; RR=0.36; 95% CI, 0.19-0.65; NNT=42). The benefit of PCD was greater in countries with low mortality rates (combined mortality and morbidity, 0.4% vs 5.7%; P <.005; NNT=19). There was no difference in maternal mortality or morbidity.