Comparison of perinatal outcomes in small-for-gestational-age newborns in breech presentation near term by delivery mode: a multicenter retrospective study

To evaluate the association between delivery mode and perinatal outcomes in small-for-gestational-age (SGA) newborns in breech presentation. A retrospective multicenter study included births between January 1, 2017, and December 31, 2022, in five maternity hospitals in the Auvergne-Rhône-Alpes region. The included newborns were delivered in breech presentation and classified at birth as small-for-gestational-age (birth weight < 10th percentile) according to AUDIPOG curves. Outcomes of spontaneous or induced vaginal deliveries were compared to those of planned cesarean sections in SGA fetuses in breech presentation. Neonatal morbidity was assessed using arterial pH at birth, 5-minute Apgar scores, and neonatal or neonatal intensive care unit admissions. Crude and adjusted associations were estimated using odds ratios (OR) and their 95% confidence intervals (CI). Among 53,006 live births, 2941 (5.5%) were breech presentations, and 176 SGA newborns were included. An arterial pH < 7.2 was significantly more frequent after vaginal delivery compared to planned cesarean (adjusted OR 4.9; 95% CI 1.59-15.2). However, no significant difference was observed for a 5-minute Apgar score < 7 (adjusted OR 0.38; 95% CI 0.061-1.7). Neonatal or NICU admissions were significantly higher in the vaginal delivery group compared to planned cesarean (adjusted OR 3.83; 95% CI 1.4-10), while no significant difference was found for NICU admission alone (adjusted OR 1.31; 95% CI 0.3-5.2). Term vaginal delivery of an SGA fetus in breech presentation is associated with lower arterial pH levels at birth, with no significant difference in 5-minute Apgar scores. These results are consistent with findings observed when comparing delivery modes for non-SGA fetuses in breech presentation.