What is the evidence for antibiotics during labor to prevent early GBS infection?
To answer this question, I will walk you through the most important studies that led to how we most commonly try to prevent early GBS infections in the U.S. today.
GBS emerged as a widespread threat to newborns in the early 1970s. At that time, 1.7 of every 1,000 infants had early GBS infection (CDC 2010). In 1973, a researcher proposed giving pregnant women penicillin to stop early GBS infections in infants (Franciosi et al. 1973).
First, researchers tried giving penicillin to women before labor, but this didnt work. Although penicillin temporarily lowered GBS levels, by the time women went into labor the GBS levels were back up again (Gardner et al. 1979).
Abbi laboring in the hospital with antibiotics for GBS.
Abbi laboring in the hospital with antibiotics for GBS.
Next, researchers tried giving antibiotics to women with GBS during labor. In the late 1980s, three groups of researchers in the U.S., Spain, and Finland randomly assigned women with GBS to either receive IV antibiotics during labor (penicillin or ampicillin) or no antibiotics (Boyer & Gotoff 1985; Tuppurainen and Hallman 1989; Matorras et al. 1991).
In a recent Cochrane review, researchers combined the results of these 3 studies that had a total of 500 pregnant women. They found that when women with GBS had antibiotics during labor, their infants risk of catching early GBS infection dropped by 83% (Ohlsson & Shah 2013).
As the Cochrane reviewers noted, there were quite a few limitations to these 3 studies. In their summary, the reviewers said There is no valid information from these three small, old, and biased trials to inform clinical practice. However, an alternative perspective would be that there is some valid information from these studies, along with some limitations to the evidence.
