In high-risk pregnant females, supplementing probiotics from the 1^st half of 2^nd trimester (14 weeks of pregnancy) up to 24 weeks of pregnancy does not decrease the risk of gestational diabetes mellitus, or improve other maternal and neonatal outcomes.

This study aimed to determine influence of probiotic supplementation during pregnancy on risk of gestational diabetes mellitus (GDM) and also other neonatal and maternal outcomes.

In this randomized, double-blind, placebo-controlled, single-center clinical trial, the recruited pregnant females (n=542, mean age 32.03 years, body mass index [BMI] 30.20 kg/m2) were randomly assigned to either probiotic supplement group (n = 271) or placebo (n = 271) group from the 1st half of the second trimester up to 24 weeks when the pregnant females were routinely assessed regarding GDM.

Each probiotic capsule (500 mg) was a mixture of Bifidobacterium bifidum, Bifidobacterium longum, and Lactobacillus acidophilus. During 24-28 weeks of pregnancy, evaluation of mothers with respect to GDM presence was done with the aid of 75 g oral glucose tolerance test (OGTT). Determination of fasting blood glucose (FBG) was also done within OGTT processes. 

In terms of FBG, OGTT-1h, OGTT-2h, and incidence of GDM, no profound differences were witnessed between the two groups, as shown in Table 1:

Regarding other studied parameters, no considerable differences was reported.

Probiotics, administered throughout the pregnancy from the 14^th week is not beneficial for minimizing GDM risk. Also, daily consumption of probiotic supplements by pregnant females does not modify any of the neonatal and mother outcomes.