Topic Overview

Some women carry group B streptococcus bacteria in their vaginal area, and it does not cause problems. (This type of strep is different from the type that causes strep throat infection.) Without knowing it, a woman who has group B streptococcus bacteria in her vagina can pass the infection to her baby during vaginal birth. The baby can then develop an infection of the tissues covering the brain (meningitis) or an infection of the blood (sepsis).

Some babies who get severe infections caused by group B streptococcus develop brain damage, hearing loss, or blindness. Brain damage can result in cerebral palsy.


Late in your third trimester, your health professional is likely to check you for group B streptococcus bacteria, particularly if you have any risk factors for the infection. If you test positive, if you have certain risk factors for group B strep, or if for some reason you aren't tested, you will receive antibiotics during labour. Antibiotics reduce the likelihood that you will pass the infection to your baby.

Antibiotic treatment is not needed if you're having a planned caesarean delivery that takes place before labour has started and before your water breaks.footnote 1



  1. Money DM, Allen VM (2013). The prevention of early-onset neonatal group b streptococcal disease. SOGC Clinical Practice Guidelines No. 298. Journal of Obstetrics and Gynaecology Canada, 35(10): 939–948. Also available online:


ByHealthwise Staff
Primary Medical Reviewer Sarah Marshall, MD - Family Medicine
Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Kirtly Jones, MD - Obstetrics and Gynecology

Current as ofMay 22, 2015