Group B streptococcus (group B strep, or GBS) is a type of bacterium that you may be carrying in your rectum or vagina and that could ultimately be transferred to the baby during delivery. Up to 40 percent of pregnant women carry the bacteria, which can come and go without symptoms from a person’s body. Newborns are at an increased risk for group B strep disease when the mother is found to have GBS colonization.
Group B strep prevention
To prevent the baby from being affected by group B strep, the Centers for Disease Control and Prevention (CDC) says you should have a dedicated screening between the 35th and 37th week of pregnancy. If found positive for GBS, you will need to be administered penicillin through intravenous therapy (IV) during delivery. If you are allergic to penicillin, notify your doctor, and other antibiotics can be provided.
The group B strep test is most accurate within five weeks of delivery
The antibiotics reduce the risk of infection from a one in 200 chance to a one in 4,000 chance. Since active prevention began in the mid-1990s, early on-set GBS has been reduced from 1.7 cases per 1,000 live births in 1993 to 0.24 cases per 1,000 live births in 2014.
The first screening is actually performed early in the pregnancy when the urine is cultured for bacterial infections. If you are found to be positive for GBS bacteriuria at that time, a further screening is not needed and you should receive antibiotics during delivery.
If you were negative for GBS bacteriuria during the urine testing, you will still need to have a dedicated group B strep screening near the time of delivery because testing within five weeks of birth is the most accurate method for predicting GBS colonization at the time of birth. The doctor will need to swab the inside of the lower vagina and the anal sphincter for lab culturing.
Group B streptococcus in newborns
Group B strep in newborns comes in two types: early onset and late onset. Early-onset GBS is the most common, but both can cause pneumonia, a lung infection; sepsis, a blood infection; or meningitis, an infection of the meninges, or the fluid and linings around the brain. Ninety-five percent of babies who acquire early- or late-onset GBS recover following antibiotics.