What is group B streptococcus?

Group B streptococcus (group B strep) is a common bacteria. It is almost always harmless in adults. In rare cases, however, a woman who has group B strep can infect her baby during delivery. This can cause serious illness in the newborn. The mother may also become very ill from the infection after the delivery.

Facts about group B strep

Even if you have group B strep, your baby will probably be healthy. Here are a few other facts about group B strep:

• group B strep is not a sexually transmitted disease (STD)
• group B strep is not the same as other strep, such as strep throat
• group B strep often has no symptoms and seldom causes problems in adults
• group B strep test results can be misleading: they may show you have group B strep one week and that you do not have it the next
• a mother who has group B strep rarely infects her newborn
• when a mother is treated for group B strep during delivery, her baby almost never becomes infected
• group B strep may become a problem if you also have other risk factors during pregnancy.

What can increase the risk?

Certain risk factors during pregnancy can increase your chances of passing group B strep to your newborn. These risk factors include:

• a urinary tract infection with group B strep
• breaking or leaking of the amniotic sac (bag of water) earlier than 37 weeks
• labour earlier than 37 weeks
• breaking of the amniotic sac more than 12 hours before labour begins
• fever during labour
• you have had another baby born with a group B strep infection.

Treatment for group B strep

If your lead maternity carer thinks your baby is at risk of group B strep infection, you will be given an antibiotic to help stop the infection. The antibiotic is given through an intravenous line during labour and delivery. This will not harm you or your baby.

If your baby becomes infected

Very rarely, group B strep can infect a baby. Symptoms may take two days or more to appear. The baby may have infections in the blood, lungs, brain or spinal cord, which will need medical treatment.

Group B strep testing

A group B strep test may be done between weeks 34 and 36 of your pregnancy. Your lead maternity carer will use cotton swabs to take cell samples from your vagina and anus. The samples are then sent to a laboratory.

Your lead maternity carer will get your test results in about two days. The results show whether you have group B strep bacteria in your genital area. These test results cannot say whether or not your baby will become infected with group B strep. They can, however, help your lead maternity carer decide whether treatment to prevent infection is needed.

Your pregnancy

Group B strep does not affect most pregnancies. If you carry group B strep there is a risk of your baby becoming infected during delivery, but you can easily be treated during labour and delivery. Ask your lead maternity carer any questions you have about group B strep.

© 2001 The StayWell Company, 1100 Grundy Lane, San Bruno, CA USA 94066-3030 www.staywell.com (0800) 333-3032. All rights reserved. Original material reviewed by the Department of Maternal Fetal Medicine, National Women’s Hospital, Auckland.