Ways to Induce Labor Part 2: GBS and Membrane Stripping

After writing the initial post about membrane stripping as a way to induce labor, there were comments that providers were telling patients that they could not strip their membranes because the patient was Group B Strep (GBS) positive, and this could cause infection. Is this based in research, or is this was just “common knowledge” that is being passed along?

Disclaimer: None of these methods should be used unless recommended by your provider, not even the “natural” methods. “Natural” does not automatically mean risk free. Some common recommendations are evidence based; others are passed on as old wive’s tales and are ineffective or possibly harmful. Normal, low risk pregnancies should not be induced prior to 39 weeks, and ideally not before 41 weeks, without a medical indication. Healthy babies will come when they are ready; taking the baby too soon can result in breathing and feeding difficulties, as well as increase the risk of c-section. Mom being uncomfortable, having difficulty sleeping, multiple rounds of false labor, or excitement for the baby to come are NOT reasons to induce. That being said, there are times when induction is appropriate, and this decision should be made with your provider.

Group B Strep (GBS) bacteria is the leading cause of early neonatal sepsis and is a common cause of maternal intrapartum infection. 20-30% of women are GBS carriers; the bacteria is present in their normal vaginal flora. Typically, women who are GBS positive will be given antibiotics (usually penicillin) in labor to prevent infection in the baby. These antibiotics need to be administered at least 4 hours prior to birth to allow them to reach therapeutic levels. Many providers are concerned that membrane stripping in GBS positive mothers will introduce the bacteria into the uterus and amniotic sac and increase the risk of infection, and will not strip membranes in a GBS positive mother.

The authors of this study note that a Cochrane review shows that stripping of membranes does not increase the risk of infection, but that the studies have not looked specifically at GBS positive women. The aim of this study was to determine whether maternal or neonatal outcomes were affected by membrane stripping in GBS positive women. Women were placed into GBS positive, GBS negative, and GBS unknown groupings. Women in the study had their membranes stripped at 40 weeks for nulliparous women, and at 41 weeks for multiparous women. “Intrapartum antibiotic prophylaxis (IAP) was administered to women with known vaginal/intestinal tract GBS colonization, documented urinary tract infection with GBS at any time during the present pregnancy, a history of an infant with GBS disease in any prior delivery, or unknown GBS status with ruptured membranes for 18 hours or more.” Nineteen clinical indicators and 4 red flag indicators were selected by an expert panel as signs of “neonatal compromise” that may indicate GBS infection. These indicators included respiratory distress starting 4 hours after birth, need for mechanical ventilation in a term baby, signs of shock, hypo or hyperglycemia, seizures, jaundice within 24 hours of birth, etc. Adverse maternal outcome measures included suspected or known chorioamnionitis, urinary tract infection or sepsis, or prolonged hospital stay.

The results of the study showed no differences in neonatal or maternal outcomes between the GBS positive, negative, and unknown mothers and infants. Of particular note, the “GBS-unknown group had similar maternal and neonatal infection rate as the other groups. This interesting group of patients, in the absence of clinical intra-partum indication for IAP [intrapartum antibiotic prophylaxis], would not generally receive antibiotic during labor and delivery. If membrane stripping would have jeopardized mothers and neonates by increasing the risk of infection, this group would potentially be the most vulnerable, since they do not receive any antibiotic protection at all. However, the fact that they did not experience a higher rate of adverse outcomes may support our conclusion that membrane stripping is a safe procedure for the mother and neonate.”

Discussion: This research shows that membrane stripping, if chosen after discussion between patient and provider, is safe even in GBS positive mothers. GBS status should not affect the decision for or against membrane stripping for labor induction.

Kabiri, D. et al. (2015). Antepartum membrane stripping in gbs carriers, is it safe? (The STRIP-G study). Public Library of Science. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0145905