Abstract: Objective To analyze the influencing factors of group B hemolytic streptococcus (GBS) infection in perinatal pregnant women and the effect of intrapartum antibiotic prophylaxis (IAP) on pregnancy outcome, so as to provide theoretical basis for eugenics. Methods 1850 pregnant women in late pregnancy who were established in Wanning people's Hospital from June 2018 to June 2020 were selected. According to the results of GBS detection of vaginal secretion, they were divided into GBS positive group and GBS negative group. The influencing factors of GBS infection in reproductive tract were analyzed by logistic regression. GBS positive patients were divided into GBS positive treatment group and GBS positive non treatment group according to the wishes of pregnant women.The pregnancy outcomes of the three groups were compared. Results ①Among 1850 pregnant women, 124 were GBS positive, and the positive rate of GBS was 6.70%. Logistic regression analysis showed that abortion history, vaginitis and gestational diabetes mellitus were risk factors for GBS infection. ②There was no significant difference in postpartum pelvic inflammatory disease, amniotic fluid pollution and postpartum hemorrhage among the three groups of pregnant women(P>0.05); The preterm birth rate of GBS positive untreated group was higher than that of GBS negative group (P<0.017). There were significant differences in the incidence of premature rupture of membranes among the three groups (P<0.017). There was no significant difference in birth weight among the three groups (P>0.05); there was significant difference in Apgar score among the three groups (P<0.05); the incidence of neonatal infectious pneumonia in GBS positive treatment group and GBS positive untreated group was higher than that in GBS negative group, and the incidence of neonatal sepsis in GBS positive untreated group was higher than that in GBS negative group (P<0.017). Conclusion The risk factors of GBS infection in pregnant women during perinatal period are abortion history, vaginitis and gestational diabetes. IAP can effectively improve the pregnancy outcome of pregnant women infected with GBS.

Key words: Pregnancy, Group B hemolytic streptococcus, Pregnancy outcome, Antibiotic, prophylactic treatment