Group B streptococcus colonization and adverse pregnancy outcomes in pregnant women: a population-based study in northern Guangdong, China.

OBJECTIVE: This study aimed to investigate the prevalence of Group B Streptococcus (GBS) colonization among pregnant women in the northern Guangdong, China, and to evaluate its association with adverse pregnancy outcomes. METHODS: A total of 13,506 pregnant women who attended prenatal care at Yuebei People's Hospital between January 1, 2020, and December 31, 2025, were enrolled. All participants had singleton pregnancies and underwent GBS screening at 35–37 weeks of gestation. Vaginal and rectal swabs were collected and tested for GBS DNA using real-time polymerase chain reaction (PCR). Demographic, clinical, and pregnancy outcome data were extracted from electronic medical records. Between-group differences were assessed using appropriate statistical tests, and multivariable logistic regression was performed to adjust for potential confounders. RESULTS: The overall prevalence of GBS colonization was 10.64% (1,437/13,506). After adjusting for potential confounders in multivariable logistic regression, GBS colonization remained independently associated with preterm birth (OR 3.04, 95% CI 2.33–3.96, p < 0.001), premature rupture of membranes (OR 2.86, 95% CI 2.44–3.36, p < 0.001), and intrauterine infection (OR 2.78, 95% CI 2.10–3.68, p < 0.001). Adverse pregnancy outcomes occurred significantly higher in GBS-positive women (31.25%, 449/1,437) than in GBS-negative women (14.31%, 1,727/12,069) (p < 0.01). Among the 1,437 GBS-positive women, 1,352 (94.1%) received intrapartum antibiotic prophylaxis. CONCLUSION: This study highlights a considerable burden of GBS colonization among pregnant women in northern Guangdong and its significant association with adverse pregnancy outcomes. Implementation of routine GBS screening and appropriate preventive strategies is recommended to reduce GBS-related maternal and neonatal complications.