Effects of Dietary Fiber on the Risk of Gestational Diabetes Mellitus in Advanced Maternal Age Women: Study Protocol for a Randomized Controlled Trial

ScopeTo investigate whether dietary fiber supplementation may reduce the risk of gestational diabetes mellitus (GDM) in advanced maternal age Chinese women (>= 35 years). Secondary outcomes include glucose metabolism, diet change, weight gain, and maternal and neonatal outcomes. Methods and resultsIn a randomized controlled trial, a dietary fiber group (19.56 g day(-1)) or control group (standard prenatal care) was conducted from 20 to 24(+6) gestational weeks in advanced maternal age women. Dietary intakes were assessed using a validated 39-item Food Frequency Questionnaire (FFQ). GDM was diagnosed by a 75 g oral glucose tolerance test (OGTT) at 25-28 weeks. After intervention, the incidence of GDM was not significantly different between groups (21.6% vs 12.9%, p = 0.165). The mean increased in carbohydrate intake in the dietary fiber group is significantly lower than in the control group (-0.94 +/- 92.12 g vs 32.27 +/- 91.81 g, p = 0.032). In addition, the glucose tolerance, weight gain between 20 and 25 weeks, and preterm birth in the intervention group have improved compared to the control group. ConclusionSupplementation with dietary fiber during pregnancy among advanced maternal age Chinese women do not lower the incidence of GDM, but improve glucose metabolism, gestational weight gain, and preterm birth.