Group B Streptococcus and Pregnancy

Group B Streptococcus (GBS) is a type of bacteria that may be present in a woman’s vagina or rectum, although it is not a sexually transmitted disease. It is usually harmless; however, if present in pregnant women, it can cause serious health problems if passed to a newborn during delivery.


Most pregnant women with GBS show no symptoms. Some may develop a urinary tract infection or infection of the uterus. However, a woman infected with GBS in the later stages of pregnancy can pass the bacteria to her baby during the delivery process causing complications for the baby. GBS symptoms in a new born baby may occur in the first 24 -48 hours following birth (early onset infections) or after 1 week to several months (late onset infections) and can lead to a blood infection, lung infection or meningitis in the newborn. Early onset infections are characterised by shortness of breath and lethargy whereas high fever, vomiting, poor feeding and irritability are characteristic of late onset infections in newborns.

Detecting GBS in pregnancy

GBS can be detected during weeks 35 and 37 of pregnancy with a culture test. Using a swab, a sample is taken from the women’s vagina and rectum and sent for laboratory testing.


If the test result is positive for GBS, IV antibiotics are given during labour to protect the newborn from contracting it from the mother. Penicillin is the commonly prescribed antibiotic but alternative antibiotics can be provided if you are allergic to penicillin.