Analysis Questions Use of Antibiotics for Group B Strep During Labor

July 18, 2014
OBGYN.net Staff
OBGYN.net Staff

Studies with poor methodology were the basis of giving prophylactic antibiotics to women in labor who are positive for group B Streptococcus, an analysis finds.

Giving antibiotics to a mother during labor to reduce early-onset group B streptococcus (GBS) is not supported by conclusive evidence, a Cochrane review has concluded.

The analysis of studies looking at the benefit of administering intrapartum antibiotic prophylaxis identified four trials involving a total of 852 GBS-positive women. In three of those trials, giving either ampicillin or penicillin did not appear to reduce newborn deaths, although the treatment did reduce early GBS infections in the newborns. Those three trials, however, were all conducted more than two decades ago, and the reviewers noted that no new trials have been done.

Pertinent Points

- The common practice of administering antibiotics to a mother during labor to reduce early-onset group B streptococcus infection is not supported by conclusive evidence.

- Poor trial design and execution likely biased the results of the trials done decades ago that led to the practice of giving GBS-positive women antibiotics during labor to prevent the infection spreading to the newborn.

- Conducting more robust trials is unlikely at this time.

In the fourth trial, which enrolled 352 women and compared intrapartum ampicillin with penicillin, reported no significant differences in neonatal or maternal outcomes between treatment groups.

Still, the authors noted that while the trial results appeared to support the use of antibiotics to reduce early GBS in infants, that poor trial design and a high risk of bias likely tainted the results. The authors were critical of both the methodology for evaluating the outcomes and the execution of the trials.

“There is lack of evidence from well designed and conducted trials to recommend IAP to reduce neonatal EOGBSD [early onset group B streptococcal disease],” the reviewers concluded.

More double-blinded controlled trials with adequate enrollment are needed to better evaluate the use of antibiotics to reduce neonatal GBS infections, they concluded. But they acknowledge that given the common practice of administering antibiotics to women who test positive for GBS, the likelihood of being able to conduct such studies is slim.

Furthermore, the authors cautioned that very few of the women in labor who are GBS positive give birth to babies who are infected with GBS and antibiotics can have harmful effects on both mother and baby. Some of the concerns they had with giving antibiotics included: severe maternal allergic reactions, increase in drug-resistant organisms and exposure of newborn infants to resistant bacteria, and postnatal maternal and neonatal yeast infections.