What is the treatment of choice for Group B Strep prophylaxis in pregnant women with low risk allergy?

For Group B Streptococcus (GBS) prophylaxis in pregnant women who are considered to have a low risk allergy to penicillin, the treatment of choice is ampicillin. This is because ampicillin is effective against Group B Strep and is widely recommended due to its safety profile and efficacy in both maternal and neonatal outcomes. It is the preferred antibiotic for intrapartum prophylaxis, which significantly reduces the risk of early-onset GBS infection in newborns.

In pregnant women with an allergy to penicillin, alternative options such as clindamycin or vancomycin may be considered, particularly in cases of a high-risk allergy or if the GBS strain is known to be resistant to penicillin. However, these agents may not be as effective as ampicillin, and resistance patterns can vary, which makes them less reliable as first-line agents.

Cephalexin, while a cephalosporin and generally safe, is not typically recommended for GBS prophylaxis in the same way as ampicillin, especially considering the complexities of penicillin allergy and cross-reactivity. Thus, ampicillin remains the first-line choice for low-risk allergy cases when treating GBS in pregnancy.