Prenatal Test – Group B Strep

The Group B Strep test screens for potentially dangerous Group B streptococcus, or GBS infection.  This test is usually routinely done during weeks 35 to 37 of your pregnancy.  Group B can be carried by anyone, but few become sick from it.  This infection is different than the infection that causes strep throat.  During pregnancy it is particularly important because it can be transmitted to the baby during birth and become harmful to the baby.

If your doctor doesn’t offer this test, you may want to ask for it.  Some doctors and midwives will bypass the testing and go ahead with treatment if you have one (or more) of several risk factors including preterm labor, fever during labor, your water breaking before 37 weeks, a prior child with GBS, or presence of GBS in your urine.

This test is quick and painless and is often conducted while your doctor is checking for dilation during your last weeks of pregnancy.  It includes the doctor or midwife taking a swab of your vagina and rectum.  The sample is sent out to a lab for a culture.  If your test results show the presence of GBS you’ll be treated with IV antibiotics during your labor and delivery.  Less than 1 out of every 200 pregnant woman who carry GBS babies will actually develop an infection.

A baby who becomes infected with GBS symptoms varies.  They may suffer from pneumonia, blood infection (sepsis), or meningitis.  Treatment for infected babies includes IV antibiotics for around 10 days, which is very effective in most cases, around 95% of babies will recover normally.  Still the infection can be quite serious and can be avoided in most cases by conducting the GBS test.

Prenatal Test – Group B Strep