Neonatal outcomes of twins according to birth order, presentation and mode of delivery: a systematic review and meta-analysis

Background The optimal mode of delivery for twins is undetermined. Objective To review literature regarding the neonatal outcomes following twin delivery. Data sources Searches were conducted in PubMed, Medline, Embase, Cochrane library and reference lists. Selection criteria Studies selection criteria were: both twins alive at labour, outcomes stratified for birth order, presentation, planned and actual delivery mode. Eighteen articles were included in the meta-analysis (39 571 twin sets). Data collection and analysis The Meta-analysis of Observational Studies in Epidemiology guidelines were followed. Interstudy heterogeneity (I-2) was tested. A fixed model was generated whenever I-2 < 25%. Pooled odds ratios (OR) with 95% CI were computed. Intergroup comparison was significant if 95% CI did not encompass 1. The first and second twins were indicated as Twin A (TA) and Twin B (TB), respectively. Main results Neonatal morbidity was lower in TA than TB (3.0 versus 4.6%; OR 0.53; 95% CI 0.39-0.70). TA experienced neonatal death less often than TB (0.3 versus 0.6%; OR 0.55; 95% CI 0.38-0.81). No differences were noted between vertex and non-vertex and attempted vaginal delivery versus planned caesarean section in either TA or TB. In TA, neonatal morbidity was lower after vaginal delivery (1.1%) than caesarean section (2.2%; OR 0.47; 95% CI 0.27-0.82). Neonatal death was not associated with actual delivery mode. In TB, morbidity following combined delivery (19.8%) was higher than after vaginal delivery (9.5%; OR 0.55; 95% CI 0.41-0.74) or caesarean section (9.8%; OR 0.47; 95% CI 0.43-0.53). When outcomes were stratified for both presentation and delivery mode, mortality rate was lower after vaginal delivery than caesarean section for both vertex and nonvertex TB. Author's conclusion An attempt at vaginal delivery should be considered in twin pregnancies with vertex/vertex presentation.