Signs and symptoms of GBS in pregnancy

Group B streptococcus is a type of bacteria that can live normally in the bowel and genital tract. Carrying it is not the same as having an illness, and it is not usually considered a sexually transmitted infection. Because colonisation can come and go, a result reflects the time when the sample was taken.

Most pregnant people who carry GBS feel well. GBS is not typically identified by a particular discharge, smell, itching, pain, fever, or urinary change. If GBS grows in a urine sample, it may be linked with a urinary infection and your clinician will decide whether treatment is needed during pregnancy. A positive vaginal or rectal swab usually guides antibiotics during labour rather than treatment before labour.

The concern is transmission to the newborn around birth. Your maternity team may recommend a swab late in pregnancy, or use a previous result and specific pregnancy history when making a plan. GBS is separate from conditions such as [pre-eclampsia](/conditions/pre-eclampsia/), which has different symptoms and urgent warning signs.

Ask your maternity team when testing is offered locally and whether your result is recorded in your pregnancy notes. Tell them if GBS was found in your urine, if you previously had a newborn with serious GBS infection, or if you have an allergy to penicillin or another antibiotic.

If you test positive, keep the result available when you go into labour or when your waters break. Antibiotics are generally given through a vein during labour when indicated; they are timed around birth because treatment earlier in pregnancy does not reliably prevent later colonisation. Do not use vaginal washes, leftover antibiotics, or supplements to try to clear GBS without clinical advice.

Contact your maternity unit promptly if your waters break, contractions begin, or you think labour may be starting and you have been told you carry GBS. Tell the team your result even if you have no symptoms.

Seek urgent maternity advice for fever, feeling acutely unwell, heavy bleeding, severe abdominal pain, reduced fetal movement, or fluid that is green or foul-smelling. These signs can have causes other than GBS and need assessment rather than self-diagnosis. After birth, obtain urgent medical help for a newborn who is struggling to breathe, unusually sleepy, feeding poorly, has a temperature change, or is becoming floppy.

You could ask: When and how will I be screened? What does my result mean for labour? Should I receive antibiotics if GBS was found in my urine? What should I do if labour or my waters breaking happens before the result is available? Which antibiotic options are suitable if I have a medication allergy?