Probiotics in obese pregnancy do not reduce maternal fasting glucose: a double-blind, placebo-controlled, randomized trial (Probiotics in Pregnancy Study).

BACKGROUND: Recent studies have reported beneficial effects of probiotics on maternal glycemia in healthy pregnant women. Obesity significantly increases risk of impaired glucose tolerance in pregnancy, but glycemic effects of probiotics in this specific obstetric group require additional investigation.

OBJECTIVE: The aim of the Probiotics in Pregnancy Study was to investigate the effect of a probiotic capsule on maternal fasting glucose in obese pregnant women.

DESIGN: In this placebo-controlled, double-blind, randomized trial, 175 pregnant women with an early pregnancy body mass index (BMI; in kg/m²) from 30.0 to 39.9 were recruited from antenatal clinics at the National Maternity Hospital, Dublin, Ireland. Exclusion criteria were BMI <30.0 or >39.9, prepregnancy or gestational diabetes, age <18 y, multiple pregnancy, and fetal anomaly. Women were randomly assigned to receive either a daily probiotic or a placebo capsule from 24 to 28 wk of gestation in addition to routine antenatal care. The primary outcome was the change in fasting glucose between groups from preintervention to postintervention. Secondary outcomes were the incidence of gestational diabetes and neonatal anthropometric measures.

RESULTS: In 138 women who completed the study (63 women in the probiotic group; 75 women in the placebo group), mean (±SD) early pregnancy BMI was 33.6 ± 2.6, which differed significantly between probiotic (32.9 ± 2.4) and placebo (34.1 ± 2.7) groups. With adjustment for BMI, the change in maternal fasting glucose did not differ significantly between treated and control groups [-0.09 ± 0.27 compared with -0.07 ± 0.39 mmol/L; P = 0.391; B = -0.05 (95% CI: -0.17, 0.07)]. There were also no differences in the incidence of impaired glycemia (16% in the probiotic group compared with 15% in the placebo group; P = 0.561), birth weight (3.70 kg in the probiotic group compared with 3.68 kg in the placebo group; P = 0.723), or other metabolic variables or pregnancy outcomes. A secondary analysis of 110 women, excluding antibiotic users and poor compliers, also revealed no differences in maternal glucose or other outcomes between groups.

CONCLUSION: Probiotic treatment of 4 wk during pregnancy did not influence maternal fasting glucose, the metabolic profile, or pregnancy outcomes in obese women.