Effects of fructo-oligosaccharides on genitourinary tract infections and birth outcomes in pregnant women: a randomized controlled trial in Bangladesh.

backgroundGenitourinary tract infections, including bacterial vaginosis, which is characterized by the loss of Lactobacillus (LAB) in the vaginal microbiota, is a risk factor for low birth weight. The aim of this study was to examine the effects of fructo-oligosaccharide (FOS) supplementation on the incidence of genitourinary tract infections in pregnant women and the birth weights of newborns in Bangladesh.

methodsA randomized, double-blinded, placebo-controlled study was conducted in Dhaka, Bangladesh. Women in early pregnancy were randomized to the FOS or placebo groups (105 women per group), and supplements were provided daily until delivery. Stool samples were collected from women at baseline and at 24 and 36 weeks of gestation and from infants at birth for the analysis of LAB and Bifidobacterium by PCR. Vaginal swabs to test for bacterial vaginosis were collected at 18 and 30 weeks of gestation. Anthropometric measurements were taken at birth, and the newborns were followed up for 6 months.

resultsOf the 210 pregnant women, 8 had abortions, 5 refused the study product, 31 migrated, 4 had infants who were stillborn, and the neonate of 1 woman died early. The mean (SD) birth weight was 2799 (381) grams; 27 (17.0%) newborns had low birth weight (15.6% in the FOS group and 19.5% in the placebo group). Birth weight did not differ between the groups after adjusting for gestational week at birth and maternal early pregnancy BMI. Bacterial vaginoses were observed in 4.3% of women in the FOS group and 3.1% of women in the placebo group and were not statistically different between the groups. LAB colonization rates in stools of pregnant women at 24 and 36 gestational weeks did not differ between the groups. However, LAB colonization rate was higher in stools of infants in the FOS group than in those in the placebo group (68.8% in the FOS group and 51.2% in the placebo group, p = 0.024). This difference remained significant after adjusting for maternal age and LAB colonization at baseline (adjusted risk ratio (95% CI) = 1.45 (1.12-1.88), p = 0.005). The rate of Bifidobacterium colonization in the stools of infants did not differ between the groups.

conclusionsFOS supplementation did not affect bacterial vaginosis incidence in pregnant women or infant birth weight. A higher rate of Lactobacillus in the stool samples of infants whose mothers received FOS was observed. Further studies are needed to confirm these findings with a large sample size.

trial registrationThis study was registered at Clinicaltrials.gov (NCT02127225).