Differences between breech and cephalic neonates born after planned cesarean section: a systematic review.

BACKGROUND: A growing number of studies have found that breech presentation is related to preexisting diseases and may affect future fetal development. This study aimed to compare the differences between breech presentation and cephalic presentation and explore the underlying mechanisms of adverse outcomes caused by fetal station itself. METHODS: ‘PubMed’, ‘Embase’ and ‘Cochrane Library’ were searched from inception to October 21, 2022. Comparative studies containing ‘prelabor CS’ or ‘elective CS’ of cephalic and breech presentation were included. A total of 585 studies were included, and 5 studies were eligible for final research. Review Manager 5.4.1 was used for data synthesis. RESULTS: The mortality of breech group is not different from that of cephalic group (RR 0.69, 95% CI 0.09–5.13, p = 0.71). No differences in infant (< 1 year) and neonatal (0–27 days) mortality were found between the breech and cephalic presentations (RR 1.56, 95% CI 0.86–2.82, p = 0.14). However, breech group was found to have lower birth weight (p < 0.002), umbilical coiling index(p < 0.0001), and bone SOS (p = 0.03 )than cephalic group. CONCLUSIONS: The breech presentation itself may not be related to adverse pregnancy outcomes, and more attention is needed for further exploration.