Reducing the burden of early-onset neonatal sepsis is a global health priority, yet Group B Streptococcus continues to be a leading etiological agent. This research is highly relevant to obstetricians, neonatologists, and midwives as it scrutinizes the practical application of CDC and ACOG guidelines in a real-world clinical environment. The study addresses the critical challenge of the 'missed window' for prophylaxis—where patients deliver shortly after admission—and the growing complication of maternal antibiotic resistance. By identifying specific risk factors for IAP failure, this work informs evidence-based improvements in labor management. Furthermore, the focus on screening accuracy and the timing of intervention provides essential insights for reducing unnecessary NICU admissions and healthcare costs associated with neonatal infectious complications. This data serves as a vital update for practitioners seeking to optimize maternal-fetal outcomes in the face of evolving microbiological challenges.
To evaluate the efficacy of universal late-third-semester GBS screening and the clinical impact of intrapartum antibiotic prophylaxis duration on neonatal colonization and early-onset infection rates.
A retrospective cohort study was conducted at a high-volume maternal fetal medicine center involving 840 documented live births over a 24-month period. Inclusion criteria required documented rectovaginal GBS culture results at 36 0/7 to 37 6/7 weeks. Participants were categorized by GBS status and the receipt of IAP. Intrapartum data points included the type of antibiotic administered, total dosage, and the duration between the first dose and delivery. Neonatal outcomes were tracked for 72 hours post-delivery, specifically monitoring for clinical signs of sepsis, positive blood cultures, and the need for NICU admission. Statistical analysis was performed using Chi-square tests for categorical variables and logistic regression to calculate odds ratios (OR) for neonatal colonization based on IAP duration. Survival analysis was utilized to determine the threshold effect of antibiotic exposure time on neonatal outcomes, with p < 0.05 considered statistically significant.
Of the 840 participants, 218 (25.9%) tested positive for GBS during the prenatal screening. IAP was administered to 94.5% of GBS-positive individuals; however, only 62.4% received the recommended ≥4 hours of prophylaxis before delivery. Neonatal early-onset sepsis occurred in 0.9% (2/218) of the GBS-positive cohort compared to 0.1% (1/622) in the GBS-negative cohort. Notably, neonates born to mothers who received <4 hours of IAP had a significantly higher risk of colonization (OR 3.4; 95% CI: 1.8–6.5; p=0.002). Laboratory sensitivities revealed that GBS isolates were 100% sensitive to penicillin and ampicillin, but demonstrated 18.4% resistance to clindamycin and 12.1% resistance to erythromycin. In the subgroup of penicillin-allergic patients (n=68), discordant antibiotic selection was associated with a 15% increase in neonatal observation requirements. Logistic regression confirmed that inadequate IAP duration was the strongest predictor of neonatal infection (p < 0.01), outweighing maternal age or parity.
The study demonstrates that while universal screening is highly effective in identifying at-risk pregnancies, the clinical benefit of IAP is significantly compromised when the administration window is less than four hours. Furthermore, the 18.4% resistance rate to clindamycin suggests a need for routine susceptibility testing in penicillin-allergic patients to prevent prophylaxis failure. Moving forward, clinical efforts should prioritize both the timing of IAP and the potential integration of rapid intrapartum PCR testing for unscreened patients or those in preterm labor. These findings support a more nuanced approach to GBS management that balances aggressive prophylaxis with prudent antibiotic selection to combat rising resistance patterns and ensure the continued decline of neonatal early-onset group B streptococcal disease.