Group B Streptococcus (GBS) is a common bacterium that can be present in the vagina or bowel without causing symptoms. Most exposed babies remain well, but selected pregnancies benefit from antibiotics during labour to reduce the risk of early newborn infection.
How GBS is identified
GBS may be found on a vaginal or rectal swab or in a urine sample. Testing policies vary by country and health system. A result is interpreted alongside gestation, symptoms and previous pregnancy history.
Antibiotics during labour
Intravenous antibiotics may be recommended in labour after a positive test, GBS in urine, a previous baby with GBS infection or other defined risks. The aim is to reduce early-onset infection; the timing and alternative antibiotic for allergy should be documented.
If waters break or labour starts
Contact maternity services promptly and mention the GBS result. Decisions about assessment, induction and antibiotics depend on gestation, time since membrane rupture, maternal temperature and local guidance.
Newborn observation
The newborn team may recommend routine observation or additional assessment depending on whether antibiotics were received, gestation and the baby’s condition. Parents should be told which feeding, breathing, temperature or alertness changes require urgent help.
Questions worth discussing at your consultation
- Why am I being advised antibiotics in labour?
- What happens if labour is very fast?
- What alternative is used if I have a penicillin allergy?
- How will my baby be observed after birth?