Clinical trial of the effect of synbiotic supplementation compared with the placebo on pregnancy outcomes in women with gestational diabetes

Objective: The aim of this study is to determine the effects of synbiotic supplementation on biomarkers of inflammation, oxidative stress and pregnancy outcomes in patients with gestational diabetes.

Study design: Parallel double-blind (both patients and researchers) clinical trial.

Population and sample size: Among patients with gestational diabetes referred to Akbarabadi Clinic affiliated to Iran University of Medical Sciences, 60 patients will be selected according to inclusion and exclusion criteria.

Inclusion criteria: Pregnant women aged 18-40 years with gestational diabetes mellitus (GDM) at 24-28 weeks' gestation will be included in this study. Exclusion criteria: Pre-eclampsia, eclampsia, hypo and hyperthyroidism, kidney or liver diseases, taking any probiotic and/or synbiotic products, smoker, insulin therapy after GDM diagnosis.

Control group: Placebo oral capsule (Tak Gen Zist, Tehran, Iran), daily, for 6 weeks. Intervention group: Synbiotic oral capsule containing three strains of Lactobacillus acidophilus (2×109 CFU/g), Lactobacillus casei (2×109 CFU/g) and Bifidobacterium bifidum (2×109 CFU/g) (Tak Gen Zist, Tehran, Iran), 0.8 g inulin, daily, for 6 weeks.

Outcomes: High-sensitivity C-reactive protein and nitric oxide (primary outcomes). Biomarkeres of oxidative stress and pregnancy outcomes (secondary outcomes).

Due to an error, the request for an update in our website has been conducted after paper published. However, the revisions were in accordance with either the original approved proposal or with coordination with Vice Chancellor of Research at the University.

Vice chancellor for research, Iran University of Medical Sciences

To decrease potential confounding effects, all participants according to balanced blocked randomisation will be randomly allocated into two treatment groups to take either supplement or placebo. Randomization will be done by the use of Stat Trek software.

Randomization and allocation will be concealed from the researchers and participants until the final analyses are completed. Another person at the Clinic who is not involved in the trial and not aware of random sequences will allocate the numbered bottles of capsules to participants. Supplements and placebo are in the same packaging at the pharmaceutical company. Only the code is written on the packages. Patients and researcher do not know the type of drug and after analyzing the data, packet codes are decoded.