Association of antibiotic treatment for second-trimester GBS with reduced miscarriage risk: Probiotic intervention shows no benefit.

Objective: To investigate the colonization rate of group B Streptococcus (GBS) during the second trimester of pregnancy, the correlation between GBS infection and miscarriage as well as the impact of intervention on pregnancy outcomes.

Materials and methods: 228 GBS-positive pregnant women at 14 - 28 weeks of gestation were divided into 3 groups according to their preferences to receive medical intervention: group A (antibiotic group, n = 54) received oral antibiotic, group B (probiotic group, n = 96) received oral probiotic, and group C (non-intervention group, n = 78) received no drug treatment. 300 GBS-negative pregnant women were selected voluntarily and randomly as the control group (group D). The incidence of miscarriage-related conditions, negative conversion rate of GBS were compared between the 4 groups. Perinatal outcomes were compared between the GBS persistent positive and negative groups.

Results: GBS colonization rate was 14.7%. The incidence of threatened miscarriage and miscarriage in group A were 1.85 and 1.85%, both of which were lower than those in group B at 21.9 and 6.3%, and group C at 33.3 and 7.7%, with all differences being statistically significant (p < 0.05). The incidence of threatened miscarriage and miscarriage in group B and group C were significantly higher than those in group D at 3.3 and 2.7% (p < 0.05). The negative conversion rate of GBS in group A was significantly higher than that in group C (14.8 vs. 2.7%, p < 0.05). There was a difference in the incidence of fetal distress, premature delivery, premature rupture of the fetal membrane, chorioamnionitis, and neonatal infection between the continuously positive and negative pregnant women (p < 0.05).

Conclusion: GBS colonization rate was 14.7% in the second trimester of pregnancy. GBS infection can increase the risk of threatened miscarriage and miscarriage as well as the risk of adverse pregnancy outcomes. Early intervention with antibiotics can increase the negative conversion rate of GBS, reduce the incidence of threatened miscarriage and miscarriage, and ameliorate the adverse outcome of pregnancy. The effect of probiotic intervention on the negative conversion of GBS was insignificant.