Group B Strep (GBS) is a type of bacteria that causes problems for pregnant women and their newborns. It is most often found in the vagina, rectum and is sometimes detected in the initial urine culture performed at the first prenatal visit. Usually the test is performed between weeks 35 and 37. a baby who becomes infected with Group can become seriously ill; the baby may end up with blood, lung, brain and spinal cord infections. The fatality rate is 5%.
What does the test involve?
A woman is typically tested between weeks 35 & 37; there is some controversy on the timing because although she may test negative earlier she may in fact be tested positive at the time of labor. Some doctors forgo the screening and treat any pregnant woman with the following risk factors with antibiotics during labor:
- Preterm labor
- Preterm rupture of membranes
- Prolonged rupture of membranes (membranes have been ruptured for more than 18 hours before baby is born)
- Has previously delivered baby with GBS
- Has fever during labor
- Has previously tested positive for GBS in a prenatal urine culture (Note: a woman tested positive for Strep B but undergoing C-section need not be on antibiotics during labor if her delivery occurs before labor begins or rupture of membranes occurs)
What is the procedure like?
It involves taking a culture from the vagina, perineum, and rectum during pregnancy. Results take 2 days. If your test comes positive (you are carrying the bacteria) you should take antibiotics during delivery to minimize the risk of passing the infection on to your baby.