Efficacy of Fish Oil and/or Probiotic Intervention on the Incidence of Gestational Diabetes Mellitus in an At-Risk Group of Overweight and Obese Women: A Randomized, Placebo-Controlled, Double-Blind Clinical Trial.

Objective: To assess whether the risk of gestational diabetes mellitus (GDM) may be lowered and glucose metabolism improved by daily administration of fish oil and/or probiotic supplements in overweight and obese pregnant women.

Research Design And Methods: We randomized in a double-blind manner 439 women (mean 13.9 ± 2.1 gestational weeks [gw]) into four intervention groups: fish oil + placebo, probiotics + placebo, fish oil + probiotics, and placebo + placebo. Fish oil (1.9 g docosahexaenoic acid and 0.22 g eicosapentaenoic acid) and probiotic supplements ( HN001 and 420, 10 colony-forming units each) were provided for daily consumption from randomization beyond delivery. Primary outcomes were the incidence of GDM diagnosed with oral glucose tolerance test targeted at 24-28 gw and the change in fasting glucose between randomization and late pregnancy (mean 35.2 ± 0.9 gw). Insulin concentration, insulin resistance HOMA2-IR index, and pregnancy outcomes were determined, as were adverse effects related to the intervention. Analyses were by intent to treat.

Results: No differences were found among the intervention groups in the maternal and neonatal pregnancy outcomes or side effects related to the intervention ( > 0.05). The proportion of women with GDM (94 of 377; fish oil + placebo, 23 of 96, 24.0%; probiotics + placebo, 25 of 99, 25.3%; fish oil + probiotics, 26 of 91, 28.6%; and placebo + placebo, 20 of 91, 22.0%) and the change in glucose, insulin, or HOMA2-IR ( = 364) did not differ among the intervention groups ( > 0.11 for all comparisons).

Conclusions: An intervention with fish oil and/or probiotics during pregnancy seemed to be both safe and well tolerated but conferred no benefits in lowering the risk of GDM or improving glucose metabolism in overweight and obese women.