Vaginal vs. cesarean delivery for preterm breech presentation of singleton infants in California: a population-based study.

OBJECTIVE: To examine the morbidity and mortality associated with vaginal breech delivery (VBD) of premature, low-birth-weight (LBW) (< 2.5 kg) newborns as compared to delivery by cesarean section.

STUDY DESIGN: A retrospective cohort study of singleton, preterm (< 37 weeks), LBW, nonanomalous newborns in California (January 1, 1991-December 31, 1999) was performed. Neonatal morbidity and mortality by route of delivery were compared.

RESULTS: Overall, 14,417 LBW, preterm, breech newborns were delivered (14% vaginally and 86% by cesarean). There were 150,570 LBW, preterm, cephalic newborns, of whom 82% were delivered vaginally. VBD of LBW newborns in nulliparous women was associated with increased neonatal mortality in newborns weighing 500-1,000 g (OR 11.7; 95% CI 7.9, 17.2), 1,001-1,500 g (OR 17.0; 95% CI 6.8, 42.7), 1,501-2,000 g (OR 7.2; 95% CI 2.4, 21.4), and 2,001-2,500 g (OR 6.6; 95% CI 2.1, 21.2) as compared with breech delivery by cesarean in nulliparous women. Birth trauma was increased in VBD of newborns weighing 1,500-2,000 g (OR 3.8; 95% CI 1.4, 10.1) and 2,001-2,500 g (OR 4.5; 95% CI 2.6, 7.9) as compared to breech delivery by cesarean in nulliparous women. Birth asphyxia was increased in breech newborns weighing 2,001-2,500 g (OR 3.5; 95% CI 2.2, 5.6) delivered vaginally in nulliparous women as compared to cephalic vaginal deliveries.

CONCLUSION: VBD of the preterm, LBW newborn is associated with significantly increased neonatal mortality as compared to cesarean section at similar birth weights. Birth trauma (> 1,500 g) was greater with VBD as compared to breech delivery by cesarean, and asphyxia (> 2,000 g) was greater with VBD as compared to cephalic vaginal delivery, suggesting that cesarean delivery may be a safer route of delivery for preterm breech fetuses.