Gestational weight gain and preterm birth in obese women: a systematic review and meta-analysis.

Abstract

Prepregnant obesity is a global concern and gestational weight gain has been found to influence the risks of preterm birth. To assess the relationship between gestational weight gain and risk for preterm birth in obese women. Four electronic databases were searched from 18 February through to 28 April 2015. Primary research reporting preterm birth as an outcome in obese women and gestational weight gain as a variable that could be compared to the 2009 Institute of Medicine's recommendations. Two reviewers independently assessed trials for inclusion. The Newcastle Ottawa Scale was used to assess study bias. Our search identified six studies meeting the inclusion criteria; five were conducted in the USA and one in Peru. Four studies with a total of 10 171 obese women were meta-analysed. Significant heterogeneity was found between studies in the pooled analysis. Results for indicated preterm birth in obese women with gestational weight gain above the Institute of Medicine's recommendations showed increased risk (adjusted odds ratio 1.54; 95% CI 1.09-2.16). Available science on this topic is limited to special populations of obese pregnant women. Generalisable research is needed to assess the variation in risk for preterm birth in obese women by differences in gestational weight gain and class of obesity controlling for significant variables in the pathway to preterm birth. This research has the potential to illuminate new science impacting preterm birth and interventions for prevention.