The impact of pre-pregnancy body mass index and gestational weight gain on placental abruption risk: a systematic review and meta-analysis.

The aim of this systematic review was to evaluate the associations between pre-pregnancy body mass index and gestational weight gain and placental abruption.Relevant studies were identified from PubMed, EMBASE, Scopus and CINAHL. Unpublished findings from analyses of linked population-based data sets from Western Australia (2012-2015, n = 114,792) were also included. Studies evaluating pre-pregnancy body mass index and/or gestational weight gain and placental abruption were included. Two independent reviewers evaluated studies for inclusion and quality. Data including odds ratios (ORs) and 95% confidence intervals (CIs) were extracted and analysed by random effects meta-analysis.21 studies were included, of which 15 were eligible for meta-analyses. The summary ORs for the association of being underweight, overweight and obese, and placental abruption, compared to normal weight women, were 1.4 (95% CI 1.1, 1.7), 0.8 (95% CI 0.8, 0.9) and 0.8 (95% CI 0.7, 0.9), respectively. These findings remained unchanged when each study was eliminated from the analysis and in subgroup analyses. Although data were scarce, women with gestational weight gain below the Institute of Medicine recommendations appeared to be at greater risk of abruption compared with women who had optimal weight gain.Mothers that are underweight prior to or in early pregnancy are at a moderately increased risk of placental abruption.