Group B Streptococcus (GBS), a gram-positive bacterium is found in the gastrointestinal and/or genitourinary tract of up to 30% of pregnant women, and it can be passed to the baby during vaginal delivery. GBS infection in newborn babies is a major cause of meningitis (infection of the lining of the brain and spinal cord), pneumonia (infection of the lungs), and sepsis (infection of the blood) (CDC). To prevent early onset GBS disease in newborns, the medical guidelines recommend intravenous antibiotics during labor (usually penicillin, if not allergic) to all women who tested GBS positive during week 36-38 of pregnancy (ACOG Committee Opinion, 2020). Similar guidelines are in place in all Western countries.
So why is there somewhat of a controversy surrounding this recommendation? First of all, because the evidence base to determine adverse events, short and long term safety of intrapartum (during labor) antibiotic prophylaxis is limited (according to a systematic review by Seedat et al. published in 2017). Second, according to the same scientific review, up to 30% of women with GBS positive results at 35-37 weeks revert to negative by labour.
So what to do? My approach to health and prevention coaching is often based on the Health Belief Model, exploring with each individual the “health threat” and the personal benefits vs. the barriers of implementing the preventive measure, as well as their motivations and ability to successfully take action. The decision is theirs in the end, to the extent that medical and ethical codes and regulations do not dictate otherwise.
In this case, I would deconstruct the dilemma in the following way. What is the “health threat” of GBS after labor? According to the CDC and ACOG, the probability of a newborn developing early onset GBS disease is 0.5%-1% without labor antibiotics, even when the mother tested positive. The mortality rate in these babies is 4-6%. So overall, in the absence of antibiotic prevention, the mortality risk for babies born to GBS positive mothers can be 0.06%. This is assuming that all women who tested positive are truly positive at the time of labor. Subsequently, I’d clarify the benefit of antibiotic prevention to each GBS positive woman: according to the CDC, the risk of infection/death for the baby will be reduced by a factor of 20, and this could bring peace of mind to a lot of women. In terms of the “barriers” to antibiotic prevention, apart from any potential discomfort and other personal beliefs, the key one might be the limited evidence of short and long term safety, especially for the child.
Among the safety concerns mentioned in the above cited systematic review, studies found alteration of the infant microbiome especially in the short term and antimicrobial resistance, while one randomized controlled trial-deemed having methodological limitations- reported a higher long-term risk of cerebral palsy in the children. A separate new, retrospective population based study reported that prenatal antibiotic exposure is associated with a small increase in the risk of autism-spectrum disorders (ASD), especially for antibiotic exposures in the 2nd and 3rd trimester (Hamad et al, Prenatal antibiotics exposure and the risk of autism spectrum disorders: A population-based cohort study, 2019). Note that this study did not specifically examine antibiotic use during labor.
In summary, given the current risk/benefit equation, the medical guidelines concluded that antibiotic prophylaxis during labor is the correct course of action. Each individual’s appraisal of the above risks/benefits and their level of risk tolerance is different and can lead to the same or a different decision (again to the extent that the medical facilities even allow a personal choice in this situation).
My Health and Prevention Plan 