What is GBS?
In late pregnancy, your provider will want to test you for Group B Streptococcus, an organism that normally inhabits the intestinal tract of humans. It migrates from the intestines and colonizes the rectum, bladder and vaginal tracts of women. Swabbing of the rectum and vagina is typically performed around the 35th to 38th week of pregnancy to test for the presence of this bacteria. Testing positive doesn’t necessarily indicate an infection, rather that there is a colonization of bacteria is present. 15-30% of women will test positive for this bacteria and will require antibiotics during labor.
When the bacteria is found to be present from a positive test result, there is an increased risk of infection to the baby. However, to most babies it is not harmful and they’ll acquire the bacteria and a plethora of other organisms as they are exposed to the mother’s vaginal flora in labor.
GBS was found the be the leading cause of many serious infections in newborns such as pneumonia, sepsis and meningitis. Exposure to the bacteria occurs as the baby is passing through the birth canal and can also cross membranes so cesarean birth carries some risk as well. Approximately half of all babies born to GBS positive mothers will be colonized by the bacteria and according to the Center for Disease Control, 1-2% of babies will develop a life threatening GBS infection. Antibiotic prophylaxis administered to the laboring person is used to prevent early-onset infection. Rebecca Dekker, PhD of Evidence Based Birth, cited from a large study of 148,000 infants born between 2000 and 2008, that nearly all of the 94 infants who developed early GBS infection were diagnosed within an hour after birth – suggesting that early onset GBS infection probably begins even before birth.
Risk factors for GBS infection in newborn include prolonged rupture of membranes (>18-24 hours), early onset ruptured membranes, elevated body temperature during labor, birth prior to 37 weeks, African-American descent, chorioamnionitis (infection of the membranous sac surrounding the baby), and intrauterine monitoring during labor.
Testing for GBS by a bacterial culture is considered highly reliable, however it is important to note that the numbers of organisms in an individual may fluctuate. Waiting to test during week 35 to 37 yields more accurate results than testing during early pregnancy due to these fluctuations. There is a 5 week window of reliability, meaning if you test positive during pregnancy, you’re likely to be positive for the next 5 weeks.
A healthy microbiome of the gut and vaginal flora can reduce the risk of GBS colonization and decrease risk of infection for baby. Incorporating a probiotic supplement during pregnancy can inhibit the growth of harmful bacteria. Look for probiotics that contain Lactobacillus reuteri and Lactobacillus rhamnosis species in particular, as they work to support normal vaginal flora. Consider eliminating sugar and most fruits which will help balance vaginal pH. Incorporating lacto-fermented foods such as sauerkraut and yogurt will help support a healthy flora. Stress greatly impairs immunity, gut health and the microbiome. Find ways to manage stressors through meditation, journaling, massage and other relaxing activities.