Cesarean delivery is associated with lower neonatal mortality among breech pregnancies - a systematic review and meta-analysis of preterm deliveries ≤32 weeks of gestation

Objective To investigate the association between actual and planned modes of delivery, neonatal mortality, and short-term outcomes among preterm pregnancies ≤32 weeks of gestation. Data sources A systematic literature search was conducted in three main databases (PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to November 16, 2022. The protocol was registered in advance in the International Prospective Register of Systematic Reviews (CRD42022377870). Study eligibility criteria Eligible studies examined pregnancies ≤ 32nd gestational week. All infants received active care, and the outcomes were reported separately by different modes of delivery. Singleton and twin pregnancies at vertex and breech presentations were included. Studies that included pregnancies complicated with preeclampsia and abruptio placentae were excluded. Primary outcomes were neonatal mortality and intraventricular hemorrhage. Study appraisal and synthesis methods Articles were selected by title, abstract, and full text, and disagreements were resolved by consensus. Random effects model-based odds ratios with corresponding 95% confidence intervals were calculated for dichotomous outcomes. ROBINS-I was used to assess the risk of bias. Results A total of nineteen observational studies were included involving a total of 16,042 preterm infants in this systematic review and meta-analysis. Actual cesarean delivery improves survival (odds ratio, 0.62; 95% confidence interval, 0.42 to 0.9) and decreases the incidence of intraventricular hemorrhage (odds ratio, 0.70; confidence interval, 0.57 to 0.85) compared to vaginal delivery. Planned cesarean delivery does not improve the survival of very and extremely preterm infants compared to vaginal delivery (odds ratio, 0.87; 95% confidence interval, 0.53 to 1.44). Subset analysis found significantly lower odds of death for singleton breech preterm deliveries born by both planned (odds ratio, 0.56; 95% confidence interval, 0.32 to 0.98) and actual (odds ratio, 0.34; 95% confidence interval, 0.13 to 0.88) cesarean delivery. Conclusion Cesarean delivery should be the mode of delivery for preterm ≤32 weeks of gestation breech births due to the higher mortality in preterm infants born via vaginal delivery.