Risk factors for emergency caesarean section in planned vaginal breech delivery.

Purpose: To identify risk factors for emergency caesarean section in women attempting a vaginal breech delivery at term.
Methods: Data from 1092 breech deliveries performed between 1998 and 2013 at a Swiss cantonal hospital were extracted from an electronic database. Of the 866 women with a singleton, full term pregnancy, 464 planned a vaginal breech delivery. Fifty-seven percent (265/464) were successful in delivering vaginally. Multivariate regression analyses of risk factors were performed, and neonatal and maternal complications were compared.
Results: Risk factors for failed vaginal delivery were peridural anaesthesia (OR 2.05; 95 % CI 1.09-3.84; p = 0.025), nulliparity (OR 2.82; 95 % CI 1.87-4.25; p < 0.001), high birth weight (OR 1.17; 95 % CI 1.04-1.30; p = 0.006) and induction of labour (OR 1.56; 95 % CI 1.003-2.44; p = 0.048). Maternal age, height and weight; gestational age; or newborn length and head circumference were not associated with an unplanned caesarean section. The rate of successful vaginal delivery in the low risk sub-group (multiparous women without induction of labour) was 58-83 %, depending on birth weight category. The likelihood of success for the high risk sub-group (nulliparous women with induction of labour) fell below a third at neonatal birth weights >3250 g. Complication rates were low in the cohort.
Conclusions: Use of peridural anaesthesia, nulliparity, high birth weight and induction of labour were risk factors for unsuccessful vaginal breech delivery requiring an unplanned caesarean section. Awareness of these risk factors is useful when counselling women who are considering a vaginal breech delivery.