What is GBS?
Group B Strep (GBS) is a common, usually harmless bacteria that lives in the gut and lower reproductive tract. It’s typically tested in a routine prenatal visit around 36-37 weeks of pregnancy via a soft cotton swab that collects a sample from the lower vagina and rectum. If you test positive for GBS, it is standard medical protocol to offer IV antibiotics during labor as GBS can pass from the mother to baby during vaginal birth and cause severe illnesses.
Antibiotics and the microbiome
Like everything, antibiotics aren’t perfect. They don’t only target GBS. They also deplete beneficial bacteria in your microbiome, too. Your microbiome is the community of trillions of bacteria, fungi, and other microbes that live in your gut, vagina, and other areas of your body. Most of these are helpful and support processes like digestion, inflammation, and immunity. Birth and breastfeeding are early opportunities for building baby’s microbiome to set the foundation for your babe’s immune system, which is why a healthy, diverse one is important for the both of you. Because antibiotics can kill off good bacteria along with the targeted GBS, they can leave the microbiome imbalanced with less diversity. For the mother, this means less immune support. And for baby, it can mean inheriting less beneficial microbes during birth and breastfeeding which may affect early immune development (at least temporarily).
GBS status is dyamic
Your GBS status can change. Someone who tests positive this week may test negative the next. And because your microbiome is highly responsive to how you eat and live, supporting your microbiome early may lower your chances of GBS colonization and a positive GBS test, though not guaranteed. The encouraging news is you don’t have to wait for a test at 36 weeks to start taking action towards supporting your microbiome. As noted previously, nourishing your microbiome with the supports below does not guarantee a negative GBS test (and a positive result certainly doesn’t mean you did anything wrong.) These practices support overall health and benefit nearly every system in the body, from digestion and immunity to mood and energy, so they’re worth embracing at any stage of life – preconception, postpartum, menopause and beyond.
Practices to start early that are in favor of a healthy microbiome:
Fermented foods: sauerkraut, kimchi, miso, kefir
Quality probiotics (note, not all are created equal)
A nutrient-dense, whole-food diet: plant and animal foods that are in, or close to, their natural state (i.e. unprocessed or minimally processed)
Adequate fiber: legumes and beans, seeds, whole grains, fruits (with skin) and vegetables
Variety of colorful plants
Less sugar (sugar feeds the “bad” bugs)
Raw, unfiltered apple cider vinegar (½ tsp before meals)
In Summary
In most prenatal care, GBS is only briefly discussed in the late third trimester, just before testing. But learning about GBS and ways to nourish your microbiome early can help you feel more informed, prepared, and empowered throughout your pregnancy. It also gives you time to prepare questions for your provider so that you feel you have adequate information to make the best decision for your individual circumstance alongside your provider.