Medication Use Patterns and Exposure to High-Risk Medications Among Pregnant Women Seeking Counseling from a Teratology Information Service: A Nine-Year Retrospective Study

Background: Medication use during pregnancy is common; however, exposure to medications with potential fetal risks remains an important public health concern. This study aimed to characterize medication use patterns and assess exposure to potentially high-risk medications among women seeking counseling from a Teratology Information Service. Methods: This retrospective descriptive study included all consultations provided by a Teratology Information Service between January 2017 and December 2025. Maternal demographic characteristics, gestational age at consultation, medication exposures, and consultation-related data were retrospectively extracted from service records. Medications were classified according to the World Health Organization Anatomical Therapeutic Chemical (ATC) Classification System and the former U.S. Food and Drug Administration (FDA) pregnancy risk categories (A, B, C, D, and X). Vitamin and mineral supplements were analyzed separately. Polypharmacy was defined as the concurrent use of five or more medications. Results: A total of 483 consultations were evaluated, including 469 pregnant women and 14 women seeking preconception counseling. The mean maternal age was 31.1 ± 5.5 years, and the mean gestational age at presentation was 9.7 weeks. Most consultations occurred during the first trimester (81.4%). Pregnant women used a mean of 3.88 ± 2.72 medications, and polypharmacy was identified in 31.3% of cases. According to the ATC classification, nervous system drugs were the most frequently used medication group (22.7%), followed by musculoskeletal system drugs (14.7%), alimentary tract and metabolism drugs (13.0%), and anti-infectives for systemic use (11.6%). Among medications classified according to FDA pregnancy risk categories, category C drugs predominated (50.2%). Overall, 57.3% of pregnant women were exposed to at least one category D or X medication. More than half (54.8%) of category X exposures consisted of hormonal preparations. Exposure to at least one category D/X medication was significantly more frequent among women with polypharmacy than among those without polypharmacy (p = 0.006). Conclusions: High-risk medication exposure was common among pregnant women seeking teratogenic risk counseling, particularly in those with polypharmacy. These findings highlight the importance of comprehensive medication review and individualized risk assessment during pregnancy and emphasize the value of Teratology Information Services in supporting evidence-based medication counseling.