Which antibiotic is contraindicated in pregnancy due to potential fetal effects?

Doxycycline is contraindicated in pregnancy primarily due to its potential effects on fetal development. This antibiotic is part of the tetracycline class and has been associated with significant risks, such as dental staining and impaired bone growth in the fetus. The use of doxycycline during the second and third trimesters of pregnancy poses a risk for skeletal and dental development, as tetracyclines can bind to calcium present in developing bones and teeth.

In contrast, the other antibiotics listed, such as azithromycin, clindamycin, and fidaxomicin, do not carry the same level of risk for adverse fetal effects. Azithromycin is generally considered safe in pregnancy, clindamycin is used when necessary and largely has a good safety profile, and fidaxomicin is a newer antibiotic with limited data but is thought to be low risk. Therefore, when selecting an antibiotic for a pregnant patient, it is crucial to avoid those with known contraindications, such as doxycycline, to ensure the health and safety of both the mother and the developing fetus.