Effect of low-glycemic index diet advice on pregnant outcomes in women with elevated risk of gestational diabetes mellitus: A meta-analysis of randomized controlled trails

Abstract

The beneficial effect of low-glycemic index (GI) diet on gestational diabetes mellitus (GDM) has been suggested in many observational studies; however, results from intervention trials remain inconsistent. This study aims to estimate the effect of interventions with low-GI dietary advice on pregnant outcomes in women with elevated risk of GDM. PubMed, Web of Science, Embase, and Cochrane Library databases were searched for randomized clinical trials (RCTs) through March 2022. Studies reporting the effect of low-GI diet advice intervention on maternal and fetal outcomes in pregnant women with increased risks of GDM were included. Random or fixed effects model was used to calculate combined treatment effects. Publication bias was assessed via Begg's and Egger's tests and funnel plot inspection. Nine RCTs recruiting 3416 participants were included. Low-GI diet advice did not modulate the risk of GDM. Compared with control diets, low-GI diet advice significantly reduced gestational weight gain (GWG) (weighted mean differences, WMD=-0.93kg, 95% CI:-1.31,-0.55; p<0.001; n=7) and the risk of premature birth (RR=0.55, 95% CI: 0.35, 0.88; p=0.012; n=5). In subgroup analyses, the effect of low-GI diet interventions on premature birth was significant only in women with BMI higher than 30kg/m2 (RR=0.28, 95% CI: 0.10, 0.77, p=0.014; n=3); the significant effect on GWG was not altered by stratification of BMI and the type of GDM risk factors. No significant changes in other maternal and newborn outcomes were found. Low-GI diet advice interventions during pregnancy decreased GWG and the risk of premature birth in women with elevated GDM risk; however, the interventions did not significantly prevent GDM development in these women.