When and how do we test for it? Because the bacteria that make up a woman’s normal flora can change over time, we test using vaginal and, yep, rectal cultures to assess for colonization (carrying the bacteria without ill effects) between 35-37 weeks of pregnancy. The exception may include testing sooner if preterm delivery seems likely, and the test results are valid for up to 6 weeks.
So, if this isn’t harmful to me, why are you sticking a cotton swab up there and especially back there?! Unfortunately, while GBS colonization is generally not harmful to mom, it can cause infection within the uterus and be passed to her baby, where it can cause a serious infection. GBS is the leading cause of sepsis (blood infection) and meningitis (nervous system infection) in newborns.
What happens if my baby is exposed to GBS? There are two types of infections in babies: early-onset infections, which happen in the first 24-48 hours after delivery, and late-onset infections, which may occur even after the first 6 days of life. Early-onset infections are generally caused by GBS exposure in the birth canal, and certain risk factors, such as preterm birth, prolonged rupture of membranes (time after the bag of water ruptures), increase the risk of infection. The most common problems seen with early-onset GBS infection are lung infections, blood infections (sepsis), and meningitis. Late-onset GBS infections occur after the first 6 days of life. These may either be passed by maternal handling (if she is colonized) or other contact with colonized persons. Late-onset GBS infections can also contribute to meningitis and pneumonia.
How do I prevent infection in my baby? If the vaginal/rectal culture results are positive during the current pregnancy, if you’ve had a urine culture showing GBS infection earlier in the pregnancy or if you’ve had a previous baby infected with GBS, then the recommendation is for IV antibiotics during labor. If we try to treat GBS prior to labor, it may just grow back by the time your baby comes. Penicillin is the treatment of choice, although if allergic, then other antibiotics can be used, depending on the severity of the allergy. Antibiotics result in an 80% reduction in transmission to a newborn whose mother is colonized with GBS (the biggest risk for having an infected infant).
Does everyone have to be tested, I’m having a scheduled cesarean section? The recommendation is to test all woman between 35-37 weeks (or a few weeks prior to planned delivery), except those who have had a previous child with GBS infection or those with a GBS urinary tract infection during this pregnancy, as those woman require treatment regardless of any future culture results. Even those undergoing scheduled cesarean delivery still benefit from testing because if their amniotic sac (bag of water) breaks prior to their planned delivery and they are GBS positive, then their baby will need to be monitored closely for development of symptoms.
How do I know if my baby has a GBS infection? After receiving antibiotics, the chance of early-onset infection is significantly reduced, although late-onset infection is still possible. Some signs that may indicate infection in the newborn are slowness/inactivity, irritability, poor feeding, vomiting and high fever; however, while it is important to mention to your pediatrician, just because your baby has one of these symptoms doesn’t necessarily mean your infant has been infected. Believe me, not every irritable infant has GBS :)
So, in case you were wondering why we bother with rectal and vaginal cultures, it’s to determine if your child is at risk for developing complications from a highly preventable infection. Even though it can be a little uncomfortable, it’s totally worth it for a healthy new baby :)