(201) Frequent Drug Exposures During Pregnancy: A Population-Based Cohort Study with SIDIAP Database

Publication Number: 532

Background: Drug use during pregnancy has been understudied due to limited access to women participation in clinical trials for ethical concerns. Database studies are trying to fill this gap by assessing drug exposure during pregnancy and its outcomes in women and their offspring.

Objectives: To describe the frequency of different drug exposures during pregnancy.

Methods: Population-based cohort study including women aged 12-50 with at least one pregnancy episode registered in SIDIAP in 2011-2020 in Catalonia, Spain. Pregnancies were identified through an algorithm developed using data proceeding from 2 different modules in the electronic health records: 1) primary health care records; containing diagnoses (ICD-10) occurred during pregnancy and 2) sexual and reproductive health care registries; containing pregnancy-related information as date of last menstruation, gestational week, date of delivery/termination, or termination outcomes. Pregnancy episodes were classified as exposed to drugs when there was at least one dispensation from 30 days before pregnancy start date up to 30 days after pregnancy end date. We described frequency of exposure for all pregnancy episodes and by trimester for the most frequent drugs. Descriptive statistics: frequency and percentage of pregnancies exposed.

Results: We identified 380,505 pregnancy episodes in 283,435 women, being 82.4% of the episodes exposed to at least one drug: 68.9% with exposure during the 1st trimester, 52.5% in the 2nd and 46.6% in the 3rd. The most common pharmacological groups used were: iron preparations (in 45% of episodes), iodine therapy (38.7%), analgesics and antipyretics (27.1%), vitamin B12 and folic acid (19.5%), penicillins (19.2%), non-steroidal antiinflammatory drugs (14.7%), and gynecological antiinfectives and antiseptics without corticosteroids (12.4%). Iron and iodine therapy were more frequently dispensed more than once during the pregnancy period (61.1% and 68.1% of episodes, respectively), vitamin B12 and folic acid in 49.2%, and the rest were more frequently dispensed only once. Regarding frequency by trimesters, exposure to iron increased from 10.2% in the 1st trimester to 30.2% in the 2nd and 3rd trimesters. The rest of the drugs decreased during the pregnancy period.

Conclusions: The most frequent drugs during pregnancy included prenatal supplements, which increased their use throughout the pregnancy period, and drugs for acute conditions, such as analgesics and antiinfectives, decreasing their use over time. It is remarkable the high frequency of only once-dispensed supplements, considering that they should be used during all the pregnancy. Our main limitation is the lack of information on over-the-counter drugs, so we might have underreported drug exposures.