Which antibiotic does NOT cross the maternal-fetal interface?

Erythromycin and other macrolides are considered to cross the maternal-fetal interface, allowing for potential therapeutic benefits in the fetus during certain infections. The pharmacokinetics of macrolides indicate they can reach effective concentrations in fetal circulation. This feature is particularly relevant when treating infections in pregnant patients, as the goal is often to adequately treat both the mother and any potential fetal involvement.

In contrast, the other antibiotics listed, such as amoxicillin, metronidazole, and clindamycin, are generally recognized for their ability to cross the placenta and reach the fetal circulation effectively. This property is important for ensuring that necessary treatment can be provided to both the mother and fetus in cases of infections that may pose a risk to the pregnancy. Thus, understanding which antibiotics cross the maternal-fetal interface is crucial in managing infections during pregnancy, particularly regarding overuse and fetal safety.