Intrapartum antibiotic prophylaxis to prevent Group B streptococcal infections in newborn infants: a systematic review and meta-analysis comparing various strategies.

Background: Early-onset Group B Streptococcus (EOGBS) infection leads to substantial morbidity and mortality in newborn infants. Intrapartum antibiotic prophylaxis (IAP) prevents EOGBS infection, but IAP strategies vary. The approach to the provision of IAP can be risk-based, universal or a combination of the two strategies. Previous systematic reviews reported that universal strategies might be most optimal in lowering EOGBS infection, but there is no consensus. Therefore, we aimed to provide up-to-date evidence on effectiveness of different strategies by comparing perinatal outcomes.

Methods: A systematic search for EOGBS prevention strategies was performed in MEDLINE, Embase and Web of Science on May 2024. Studies were included if they reported on different strategies and outcomes of interest, including EOGBS infection, IAP administration and antimicrobial resistance regardless of publication date. Summary data was extracted from published reports. Study quality was assessed using the ROBINS-I tool. Random-effects meta-analyses were used to determine risk ratios (RR) and 95%-confidence intervals. PROSPERO registration CRD42023411806.

Findings: A total of 6293 records were identified, of which 72 observational studies were included for synthesis with more than 10 million live births. Meta-analysis demonstrated that implementation of any strategy (n = 34 studies, RR 0.46 (0.36-0.60)), risk-based strategies (n = 11 studies, RR 0.65 (0.48-0.87)), or universal strategies (n = 16 studies, RR 0.37 (0.25-0.55)) was associated with a reduced risk of EOGBS infection compared to no strategy. In direct comparison, universal strategies were associated with a reduced risk of EOGBS compared to a risk-based strategy (n = 17 studies, RR 0.41 (0.30-0.55)), while the proportion of women receiving IAP did not differ between risk-based (16%) and universal (21%) strategies (n = 9 studies, RR 1.29 (0.95-1.75)). There was no antimicrobial resistance of EOGBS isolates to penicillin or ampicillin (n = 11 studies).

Interpretation: Any IAP strategy could reduce the risk of EOGBS infection without evidence of increasing antimicrobial resistance. Universal strategies give the largest reduction in the EOGBS burden, while not exposing a significantly higher proportion of pregnancies to IAP compared to risk-based strategies.

Funding: UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction, a cosponsored programme executed by the World Health Organization.