Can infants avoid contracting Group B Strep?

Infants who are born to a person carrying Group B Strep (GBS) have a 1-2 in 100 chance of contracting GBS disease, according to March of Dimes. While most babies who contract GBS disease can be treated, about 5%, or 1 out of 20, babies will die even with treatment.

“Though rare, GBS disease in newborns can have devastating consequences,” says Emily Malloy, certified nurse midwife at Aurora Health Care.

Group B Strep bacteria was first found in cows, and now is part of the bacteria that can be found in humans, particularly in the gastrointestinal and genital tracts. Most of the time, this bacterium is not harmful, does not make the person feel sick, and can come and go inside one’s body. However, it can cause various infections like bacteremia, meningitis, sepsis, pneumonia, and cause infections in the bones and joints, skin and soft tissues, and the urinary tract. Most can be treated if taken care of right away, but life-threatening if not taken seriously, like in infants. In newborns, GBS can cause two types of illnesses, “early onset” in the first 7 days of life and “late onset” in days 7-90.

“Researchers are continuing to seek ways to prevent GBS from being present during pregnancy. Vaccine trials are ongoing, but very large numbers are needed in the trials because GBS disease in newborns is rare,” Malloy shares. “Probiotics have been suggested by midwives to reduce GBS with early promising studies, but no definitive research support exists.”

Currently, pregnant people are tested for GBS in routine screenings towards the end of their pregnancy, usually around 36 weeks. About 1 in 4 pregnant people have GBS in their vagina, per the Centers for Disease Control and Prevention. When it is identified that the pregnant person has GBS, the recommended treatment has been to give them antibiotics during labor every four hours. This has decreased the risk of babies contracting GBS considerably, but not the mortality of babies who do contract it, nor the high use of antibiotics in healthy people.

“Antibiotics are very effective at preventing GBS disease in newborns. If a GBS positive person gets antibiotics while in labor, it can decrease the chance of the baby contracting the disease from 1 in 200 to 1 in 4,000,” says Dr. Marie Forgie, obstetrics & gynecology physician at Aurora Health Care. “However, all interventions have risks. We were curious if there was something we could do to prevent GBS colonization in the first place, so fewer people would need antibiotics in labor and maybe fewer babies would become infected.”

Advocate Aurora Research Institute’s Center for Child and Family Research supported the nationally-funded study on the use of probiotics to reduce GBS during pregnancy along with other researchers across the country including Marquette University and University of Wisconsin. Physicians and midwives at Aurora Sinai Medical Center, including Malloy and Dr. Forgie, conducted the trial from 2018 to 2022 and enrolled healthy pregnant people to begin taking probiotics at 28 weeks, along with their prenatal vitamins. The goal was to see if probiotics helped decrease GBS bacteria, lessening the amount of pregnant people who have GBS at delivery, decrease the use of antibiotics and lower the rate of newborns effected by GBS. The study found that the participants who took probiotics were 5% less likely to get GBS, although a larger study is needed to identify if this finding is significant.

“We are excited about our early findings,” says Malloy. “Our team is currently working on writing a larger, more definitive study of probiotics against GBS.”

Learn more about clinical trials and research at Advocate Aurora Research Institute.