Maternal prepregnancy overweight and obesity and the risk of preeclampsia: A meta-analysis of cohort studies

•The site selection of included studies was extensive.•Location of study in statistical models may be the source of heterogeneity.•Prepregnancy maternal overweight and obesity is a risk factor for preeclampsia. The aim of our meta-analysis was to explore whether overweight and obesity was associated with preeclampsia or not. Three databases were systematically reviewed and reference lists of relevant articles were checked. Meta-analysis of published cohort studies comparing whether overweight and obesity was associated with preeclampsia and adjusting for potential confounding factors. Calculations of pooled estimates were conducted in random-effects models. Heterogeneity was tested by using Chi-square test with Cochrane and heterogeneity was explored with meta-regression. Publication bias was estimated from Egger’s test (linear regression method) and Begg’s test (rank correlation method). Nineteen studies met the inclusion criteria. The meta-analysis showed that overweight and obesity was associated with an increased risk of preeclampsia. The aOR calculated for 13 studies (compared overweight to normal weight) was 1.71, 95% CI (1.52, 1.91) for random-effects models and 19 studies (compared obesity to normal weight) was 2.48, 95% CI (2.05, 2.90) for random-effects models, stratified analyses showed no differences regarding quality grade, location of study and period of anthropometric measurement. There was no indication of a publication bias either from the result of Egger’s test or Begg’s test. Our results suggested that prepregnancy maternal overweight and obesity are significantly associated with an increased risk of preeclampsia.