Impact of probiotics in women with gestational diabetes mellitus on metabolic health: a randomized controlled trial

OBJECTIVE: Probiotics are live microorganisms that may confer health benefits on the host. Recent trials of probiotic use among healthy pregnant women demonstrate potential for improved glycemic control. The aim of this study was to investigate the effects of a probiotic capsule intervention on maternal metabolic parameters and pregnancy outcome among women with gestational diabetes. STUDY DESIGN: This double-blind placebo-controlled randomized trial recruited pregnant women with a new diagnosis of gestational diabetes or impaired glucose tolerance following a 3-hour 100-g glucose tolerance test. Women were randomized to a daily probiotic (Lactobacillus salivarius UCC118) or placebo capsule from diagnosis until delivery. Fasting blood samples were collected at baseline and 46 weeks after capsule commencement for analysis of glucose, insulin, c-peptide, and lipids. The primary outcome was difference in fasting glucose postintervention, first analyzed on an intention-to-treat basis and followed by per-protocol analysis that excluded women commenced on pharmacological therapy (insulin or metformin). Secondary outcomes were changes in insulin, c-peptide, homeostasis model assessment and lipids, requirement for pharmacological therapy, and neonatal anthropometry. RESULTS: Of 149 women recruited and randomized, there were no differences between the probiotic and placebo groups in postintervention fasting glucose (4.65 +/- 0.49 vs 4.65 +/- 0.53 mmol/L; P = 373), requirement for pharmacological therapy (17% vs 14%; P = .643), or birthweight (3.57 +/- 0.64 vs 3.60 +/- 0.57 kg; P = .845). Among 100 women managed with diet and exercise alone, fasting plasma glucose decreased significantly within both the probiotic (4.76 +/- 0.45 to 4.57 +/- 0.42 mmol/L; P < .001) and placebo (4.85 +/- 0.58 to 4.58 +/- 0.45 mmol/L; P <. 001) groups, but the levels between groups did not differ (P = .316). The late gestation-related rise in total and low-density lipoprotein (LDL) cholesterol was attenuated in the probiotic vs the placebo group (+0.27 +/- 0.48 vs +0.50 +/- 0.52 mmol/L total cholesterol, P = .031; +0.08 +/- 0.51 vs +0.31 +/- 0.45 mmol/L LDL cholesterol, P = .011). No differences were noted between groups in other metabolic parameters or pregnancy outcome. CONCLUSION: A probiotic capsule intervention among women with abnormal glucose tolerance had no impact on glycemic control. The observed attenuation of the normal pregnancy-induced rise in total and LDL cholesterol following probiotic treatment requires further investigation, particularly in this obstetric group at risk of future metabolic syndrome.