Managing Urinary tract infections in pregnancy: teratogenic risks, molecular mechanisms, and antibiotic safety

Urinary tract infections are among the most common bacterial infections during pregnancy and are associated with adverse maternal and fetal outcomes, including pyelonephritis, preterm birth, and low birth weight. Selecting appropriate antibiotics requires balancing effective infection control with minimizing teratogenic risk and accounting for pregnancy-related physiological changes.

This narrative review summarizes the teratogenic potential, safety profiles, pharmacokinetic alterations, and molecular mechanisms of antibiotics used for UTIs during pregnancy. A comprehensive literature search was conducted using PubMed, Scopus, ScienceDirect, and Google Scholar, with emphasis on studies published within the last few years. Evidence relating to penicillins, cephalosporins, nitrofurantoin, aminoglycosides, fluoroquinolones, and co-trimoxazole was critically evaluated, together with mechanistic insights involving oxidative stress, mitochondrial dysfunction, and disruption of Wnt, SHH, BMP, and TGF-β signaling pathways.

Current evidence supports penicillins and cephalosporins as the preferred antibiotics during pregnancy because of their well-established fetal safety profiles. Nitrofurantoin remains an appropriate option when used judiciously, whereas aminoglycosides, fluoroquinolones, and co-trimoxazole should be reserved for carefully selected clinical situations owing to their potential fetal toxicities. Trimester-specific risk assessment and pregnancy-adapted pharmacokinetic considerations remain fundamental to optimizing maternal and fetal outcomes.