Preventing GBS in Pregnancy
A common concern in the third trimester in pregnancy is GBS (group B strep). This common bacteria is found in 10 – 35% of all healthy, adult women (in the vagina, rectum and urinary bladder). It’s normally kept in check by the lactobacillis strains, but can certainly overgrow. While most women don’t experience any symptoms associated with GBS, it can be passed to baby during birth. This may lead to primary neonatal sepsis, pneumonia and meningitis during the baby’s first week of life.
Risk factors for GBS include:
Multiple sexual partners
Male-to-female oral sex
Frequent or recent sex
Less than 20 years old
History of vaginal infections
Previous GBS+ pregnancy
When does the GBS swab happen?
A culture test is typically done to determine if a woman is GBS positive or negative. At 35-37 weeks a woman’s rectum and vagina are swabbed with a Q-tip, which is then sent for culture. If the woman tests as GBS+, she’ll be given antibiotics during labour, or if her membranes break early.
According to the SOGC, once women are tested at 35-37 weeks, they’re not tested again. Which means that if we want to get ahead of the game, and help cultivate a health vaginal microbiome – then we need to do so early.
A 2016 study looked a how probiotics could affect vaginal flora after a woman has tested positive with GBS. Ninety-nine women were were all diagnosed by GBS culture as being GBS positive between 35 to 37 weeks. They were then split into two groups – treatment and placebo group. The treatment group took 2 oral probiotics capsules before bed (containing L. rhamnosus GR-1 and L. reuteri RC-14) until delivery, and the placebo group took 2 placebos before bed until delivery.
At time of delivery, the women were re-tested (vaginally and rectally) to determine if they were still GBS positive. In the probiotic group 42.9% in women were no longer GBS positive, whereas in the placebo group, only 18% were no longer GBS positive. This is obviously quite exciting as those two probiotic strains had a positive effect on the microbiome and reduced GBS colonization!
As I previously mentioned, the SOCG does not recommend re-testing moms who tested positive for GBS at the time of birth (although your Midwife may do so). Therefore, we need to be proactive about this and improve the vaginal microbiome before the GBS swab is done.
The beginning of the third trimester is a great time to establish a foundation of healthy gut flora, boost immune function, and ensure that your diet is conducive to a healthy gut.
Women who have a history of UTIs and bladder infections or were GBS positive during a previous pregnancy, may benefit from seeking support early on in pregnancy (such as during the first trimester).
How I Treat It
At 32-33 weeks, I encourage women to book an appointment with me to prepare their vaginal microbiome for the GBS swab. I prepare the vaginal microbiome by recommending a probiotic and herbal immune support (that are safe to take during pregnancy) like garlic and echinacea to support vaginal health.
If you tested positive for GBS in prior pregnancies, I recommend booking an appointment at the beginning of the third trimester to begin to support vaginal health. I follow the same protocol as above, but treat for longer to help change the vaginal flora especially if you have had GBS before.
If you have a history of GBS, UTI and/or yeast infections, and are hoping to improve your vaginal flora – book an appointment with me! We’ll work together to get your bacteria back in line, and hopefully stop those vaginal infections for good!
Ho M, Chang Y, Chang W et al. Oral Lactobacillus rhamnosus GR-1 and Lactobacillus reuteri RC-14 to reduce Group B Streptococcus colonization in pregnant women: A randomized controlled trial. Taiwanese Journal of Obstetrics and Gynecology. 2016;55(4):515-518. doi:10.1016/j.tjog.2016.06.003.
Management of Group B Streptococcal Bacteriuria in Pregnancy
Note: This article only discusses research in preventing a GBS+ colonization prior to a GBS culture done by an OB/GYN or midwife. It purposefully does not discuss what to do in the case of a positive GBS+ test.