How should I manage a pregnant patient who tests positive for GBS during routine screening?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025Updated: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

If a pregnant patient tests positive for Group B Streptococcus (GBS) during routine screening, the primary management is to offer intrapartum antibiotic prophylaxis to reduce the risk of early-onset neonatal infection.

Specifically, antibiotics should be given during labour to women who have GBS colonisation detected in the current pregnancy.

The first dose of antibiotics should be administered as soon as possible after labour starts and continued until the birth of the baby.

The choice of antibiotic depends on the presence or absence of penicillin allergy: for women without penicillin allergy, benzylpenicillin is recommended; for those with a non-severe penicillin allergy, a cephalosporin such as cefotaxime may be used with caution; and for severe penicillin allergy, vancomycin or an alternative antibiotic active against GBS should be considered.

Women with prolonged prelabour rupture of membranes between 34 and 37 weeks’ gestation who have GBS colonisation should be offered immediate birth by induction or caesarean section.

Throughout labour, monitor for any new risk factors or clinical indicators of neonatal infection and perform appropriate assessments if concerns arise.

Educational content only. Always verify information and use clinical judgement.