Who has it, when, why, and what the results mean.
When is the test taken?
The Group B strep test, which screens for potentially dangerous Group B streptococcus (GBS) infection, is usually given during weeks 35 to 37.
Who needs to take the test, and why?
Many healthcare providers routinely test all pregnant women for Group B streptococcus, a bacterium that lives in the reproductive and genito-urinary systems. Group B strep (which is different from Group A streptococcus, the kind that gives you strep throat) can be present in anyone, but few people become sick from it. It is a concern during pregnancy, however, because it can cause urinary tract and uterine infections, and, if it is transmitted from mother to baby during birth, it can be very harmful to the baby. If your doctor doesn't offer the test, you may want to ask for it: The Centers for Disease Control and Prevention currently advise all healthcare providers to give the test to any patient who requests it.