Effect of mode of delivery on perinatal outcome in severe preterm birth: systematic review and meta‐analysis

Abstract

ObjectiveTo review the evidence on the effect of the mode of delivery on perinatal outcomes of fetuses born before 32 gestational weeks (GW).MethodsMEDLINE, Scopus, Cochrane Central Register of Controlled Trials (Central), the US Registry of clinical trials (www.ClinicalTrials.gov) and grey literature sources were searched, starting from the year 2000, to reflect contemporary practice in perinatal care. Non‐randomized trials that included singleton fetuses, without chromosomal abnormality or major congenital defects, and were born either vaginally or via cesarean delivery, were included in the analysis. Primary outcomes were neonatal death, defined as death in the first 28 days of life, and survival at discharge. Secondary outcomes were other adverse perinatal outcomes. ROBINS‐I tool was used to assess the risk of bias. The overall quality of the evidence for the outcomes was assessed per GRADE. Summary odds ratios (ORs) with 95% confidence intervals (CI) were calculated, and random effects models were used for data synthesis. Subgroup analyses were performed for births before 28 gestational weeks, and births between 28 and 32 gestational weeks, and according to presentation at delivery.Results27 retrospective studies (22317 neonates) were included in the meta‐analysis. All studies reported on singleton pregnancies. Vaginal birth significantly increased the risk of neonatal death (N=1496 neonates) of fetuses born <28w, when all presentations were analyzed (OR 1.87, 95%CI 1.05‐3.35; I2 65%, very low quality), and in breech (N=733) (OR 3.55, 95%CI 2.42‐5.21; I2 21%, moderate quality), while the odds of survival at discharge (N=646) were significantly decreased among the latter as well (OR 0.36, 95%CI 0.24‐0.54; I2 21%, low quality). For breech fetuses born between 28 and 32 gestational weeks, vaginal birth increased the risk of perinatal death (N=1581) (intrapartum and neonatal) (OR 3.06, 95%CI 1.47‐6.35; I2 0%, high quality). In non‐cephalic fetuses born between 24 and 32 gestational weeks, vaginal birth decreases the odds of survival at discharge (N=1068) (OR 0.34, 95%CI 0.22‐0.52; I2 16%, moderate quality).ConclusionThis meta‐analysis suggests that vaginal birth in severe preterm births is associated with an increased risk of neonatal and perinatal death in breech fetuses, while an effect could not be demonstrated in cephalic fetuses.This article is protected by copyright. All rights reserved.