Stage-Specific Pathogen and Risk Factors in Pregnancy, Parturition, and Puerperium: A Retrospective Cohort Study

Abstract Background Maternal sepsis remains a leading cause of pregnancy-related morbidity and mortality. Physiological adaptations during gestation complicate early sepsis recognition, while delayed source control exacerbates risks. Stage-specific variations in pathogen and modifiable risk factors have not been adequately studied. Methods This retrospective cohort study analyzed pathogen profiles and infection systems in pregnany, perinatal, and puerperal patients undergoing pathogen testing at Gansu Provincial Maternal and Child Health Hospital from January 2020 to December 2024. Logistic regression was used to identify risk factors, with unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) reported. Results A total of 193 maternal were included, with 28 cases of sepsis and 165 non-sepsis cases. Bacterial pathogens dominate in perinatal stages, peaking at parturition. Maternal infection sites exhibited a distinct perinatal pattern: the lowest rates occurred during pregnancy (predominantly genital, respiratory, and urinary tract infections), peaked in the perinatal period (primarily genital and respiratory infections), and declined during the puerperium (with genital infections and newly emerging urinary tract and surgical site infections). Specific like Escherichia coli, Enterococcus faecalis, and Mycoplasma show stage-specific abundance changes. During perinatal, several factors were significantly associated with an increased risk of sepsis. Notably, maternal operation was strongly associated with sepsis (OR = 6.87, 95% CI: 1.76–26.74), Additionally, maternal anemia (OR = 3.83, 95% CI: 1.26–11.67) and hypoproteinemia (OR = 5.72, 95% CI: 1.68–19.54) were also significantly linked to higher odds of sepsis. Conclusion Maternal sepsis demonstrates distinct stage-specific microbial, with bacterial dominance and genital tract infections surging during perinatal. Hypoproteinemia, anemia, and surgical history are critical modifiable risk factors, underscoring the need for targeted interventions during high-risk perinatal phases.