Group B Strep (GBS) During Pregnancy
Group B streptococcus (GBS) is a type of bacteria that normally grows in the vagina and/or rectum of healthy women, but which can cause problems during pregnancy.
A pregnant mother can pass this bacteria to her baby during delivery, so routine screening for vaginal group B strep (GBS) is recommended for all pregnant women between the 35th and 37th week of pregnancy.
The test involves a swab of both the vagina and the rectum. The sample is then taken to a lab where a culture is analyzed for any presence of the bacteria. Test results are usually available within 1-2 days.
How does someone get group B strep?
The bacteria that causes group B strep normally lives in the intestine, vagina, or rectal areas. Group B strep colonization is not a sexually transmitted disease (STD). Approximately 15-40% of all healthy women carry group B strep bacteria. For most women there are no symptoms of carrying the group B strep bacteria.
What if I test positive for group B strep infection?
If you test positive for GBS this simply means that you are a carrier. Not every baby who is born to a mother who tests positive for GBS will become ill. Approximately one of every 100 to 200 babies whose mothers carry GBS will develop signs and symptoms due to infection with GBS.
There are, however, symptoms that may indicate that you are at a higher risk of delivering a baby with GBS. These symptoms include:
- Labor or rupture of membrane before 37 weeks
- Rupture of membrane 18 hours or more before delivery
- Fever during labor
- A urinary tract infection as a result of GBS during your pregnancy
- A previous baby with GBS disease.
How can I protect my baby from group B strep infection?
If you test positive for GBS and meet the high risk criteria, then your physician will recommend giving you antibiotics through IV during your delivery to prevent your baby from becoming ill. Taking antibiotics greatly decreases the chances of your baby becoming ill.
For women who are group B strep carriers, antibiotics before labor starts are not a good way to get rid of group B strep bacteria. Since they naturally live in the gastrointestinal tract (guts), the bacteria can come back after antibiotics. A woman may test positive at certain times and not at others. That’s why it is important for all pregnant women to be tested for group B strep between 35 to 37 weeks of every pregnancy.
If you are at a low risk, the decision to use antibiotics will be tailored to the mother's individual medical needs.
How does Group B Strep infection affect a newborn baby?
Babies may experience early or late-onset of group B strep disease.
Early onset GBS disease may be present in a baby that becomes sick within hours of delivery. Signs of illness may including breathing problems, difficulty eating, poor urination, change in skin tone and low blood pressure.
Newborns with early-onset are treated the same as the mothers, which is through intravenous antibiotics.
Late-onset GBS disease may be present in a baby that becomes sick within a week or a few months of delivery. Newborns with late onset GBS are at risk of developing meningitis. It could be a result of delivery, or the baby may have contracted the bacteria by coming into contact with someone who has GBS. Late-onset disease is not as common as early onset GBS disease.
Frequently Asked Questions about GBS Disease
How serious is GBS? GBS can cause bladder infections and womb infections for the mother. In some cases GBS can cause stillbirth. Newborns can get meningitis, sepsis, and pneumonia.
If I test positive for GBS does that mean my baby is going to get it also? No. Approximately 1 of every 100-200 babies who are born to mothers who carry GBS will become ill.
What percentage of babies born to mothers with GBS will actually become ill? Approximately 1 of every 100-200 babies born to mothers with GBS will become ill. However, there are certain symptoms that put a mother at a higher risk than others.
What can I do to prevent my baby from getting GBS disease? Intravenous antibiotics (antibiotics given through IV) are recommended during delivery to reduce the chance of your baby becoming sick.
Is Group B Strep related to strep throat? No, Group B strep is different from Group A strep bacteria that causes cellulitis, strep throat and other infections.
Can a woman who tests positive take oral antibiotics before delivery? Treating the mother with oral antibiotics during the pregnancy may decrease the amount of GBS for a short time, but it will not eliminate the bacteria completely and will leave the baby unprotected at birth. Also, waiting to treat the baby with antibiotics after birth is often too late to prevent illness.
Are antibiotics safe for the baby? Penicillin is commonly used during pregnancy in non-allergic patients. There are substitute drugs for those who are allergic to penicillin, but they could still experience an allergic reaction. It is best to discuss the pros and cons with your health care provider.