Systematic review of clinical trials on dietary interventions to prevent excessive weight gain during pregnancy among normal weight, overweight and obese women

Abstract

Background: Excessive weight gain during pregnancy and subsequent postpartum weight retention may contribute to the epidemic of obesity among women of childbearing age. Preventing excessive gestational weight gain (GWG) to optimize maternal, fetal and infant wellbeing is therefore of great importance. A number of dietary interventions in this area has been conducted with inconsistent results, which has made it difficult to identify effective strategies to prevent excessive weight gain during pregnancy among normal weight, overweight and obese women. The primary objective of this review was to evaluate the effect of dietary interventions for reducing GWG. The secondary objective was to examine the impact of these interventions on different child and maternal health outcomes.

Method: The PUBMED, the Cochrane Central Register of Controlled Trials (CENTRAL) and the LILACS databases were searched for relevant articles. All published randomized controlled trials (RCT) and quasi-randomized controlled trials (QCT), with concurrent controls, on dietary interventions during pregnancy were considered. Results were presented using relative risk (RR) for categorical data and weighted mean difference (WMD) for continuous data. Data were primarily analyzed with a fixed-effect model and a random-effects model was used in the presence of heterogeneity. No date and language restrictions were applied.

Results: In total, 13 studies were included in this review and 10 trials contributed data on total GWG. Dietary intervention significantly reduced total GWG (n = 1434; WMD = -1.92 kg; 95% CI = -3.65/-0.19; p = 0.03), weight retention at six months postpartum (n = 443; WMD = -1.90 kg; 95% CI = -2.69/-1.12; p < 0.0001) and incidence of cesarean section (n = 609; RR = 0.75; 95% CI = 0.60/0.94; p = 0.013). However, dietary intervention had no significant effect on weight retention at six weeks postpartum, birth weight, preeclampsia, gestational diabetes and preterm birth.

Conclusion: Dietary advice during pregnancy appears effective in decreasing total GWG and long-term postpartum weight retention, but so far there is limited evidence for further benefits on infant and maternal health.

Figures

Figure 1

Flow chart of the selection process for eligible studies.

Figure 2

Weighted mean difference in total gestational weight gain between intervention and control groups. The overall effect size was estimated by weight mean difference using inverse variance method. Weights are from random effects analysis. The black dot represents the point estimate of each study, square size represents the weight of each study in the meta-analysis and the horizontal lines represent the respective 95%CI. The vertical solid line represents WMD of zero or line of no effect. The diamond represent the overall pooled estimate effect of the dietary intervention.

Figure 3

Funnel plot of the SE by weighted mean difference (WMD) using random effect model for assessment of publication bias. The vertical solid line represents the pooled estimate (WMD) and the diagonal dashed lines represent the pseudo 95%CI around the pooled estimate. The vertical dotted line represents the WMD of zero or line of no effect. Each circle represents a study applying caloric restriction and each triangle is a study not applying caloric restriction.

Figure 4

Funnel plot of the SE by weighted mean difference (WMD) using fixed effect model for assessment of publication bias. The vertical solid line represents the pooled estimate (WMD) and the diagonal dashed lines represent the pseudo 95%CI around the pooled estimate. The vertical dotted line represents the WMD of zero or line of no effect. Each circle represents a study applying caloric restriction and each triangle is a study not applying caloric restriction.