This article is from the Group B Strep FAQ, by email@example.com (Cheryl Sandberg) with numerous contributions by others.
The GBS Association advocates that every pregnant woman be screened for
GBS. One third, or 1,200,000 pregnant women carry GBS Bacteria. Knowing
your culture result before you go into labor can help protect your baby's
The test should be performed late in pregnancy, around 35 -37 weeks of
gestation. The test involves collecting a swab or swabs from the lower
vagina and rectum and culturing the sample on a special medium (LIM or
selective broth medium). The test result is usually ready in 2 or 3 days and
it usually costs between $15 and $35. This culture is considered the "Gold
Standard"-- *It is the best screening available*. Unfortunately, it is not
perfect and may miss a small number of women (approx 5%) who carry GBS.
Fortunately, it is accurate in detecting the bacteria as the "Gold
Standard" culture but may be beneficial in a setting where a pregnant woman
had not received prenatal care.
A positive culture result means that the mother is colonized with GBS. It
does *NOT* mean that she has GBS disease or that her baby will become ill.
Rather, a positive test means that a woman and her doctor need to plan for
her labor and delivery with this test result in mind. The results of GBS
cultures should be available at delivery. If they are not available a woman
should not hesitate to tell a doctor or nurse her results as soon as she
arrives in the Labor and Delivery ward.
If you are pregnant, ask your health care professional about testing for
GBS. If the test is not offered, you should request it. Ask to be cultured
for GBS during pregnancy, discuss treatment plans with your doctor, and
tell your baby's doctor, pediatrician, or newborn nursery nurse about your
culture result. By doing these things you can help prevent a GBS infection.