Study on perinatal group B Streptococcus carriers and the maternal and neonatal outcome

Objective: To investigate the group B streptococcus (GBS) colonization rate and the relationship between vaginal colonization of GBS and the maternal and neonatal outcome.

Methods: 3% TH selective broth media were used for culture of GBS. The vaginal samples were collected during different pregnant periods (before 20 weeks' gestation; 20-28 weeks; after 34 weeks' gestation) and other samples from different sites after labor (including neonatal throat, ear, umbilicus and placenta, umbilical blood, maternal blood, etc).

Results: The GBS carrier rate in 1 039 pregnant women was 11.07% (115/1,039). The colonization rate of different treating times was 29.73% (test three times), 15.50% (test twice) and 9.86% (test one time) respectively. The carrier rate of three-time-test was significantly higher than that of two times test (P < 0.01) and that of only one time (P < 0.01). The carrier rate in three periods was 16.84% (< 20 weeks), 18.40% (20-28 weeks) and 14.90% (> 34 weeks) respectively. Obstetric complications associated with GBS carrier were similar with those of non-carrier. Neonatal carrier rate was 9.95%. The neonatal carrier rate in the group of carrier mothers was higher than that of non-carrier mothers (14.29%:7.26%). The rate of neonatal pneumonia and the upper respiratory tract infection in GBS-carrier-mother was higher than that of non-carrier mothers (11.01%:9.71%; 8.27%: 6.07%) while it was similar in neonatal carrier group and non-carrier group (20.00%:14.92%; 10.00%:4.97%).

Conclusions: GBS might be one of vaginal pathogens in Chinese women, but it is not severe enough to threaten the health of pregnant women and their newborns.