Association Between First-Trimester Medication Exposure in Pregnancy and Congenital Anomalies: A Scoping Review of Cohorts, Exposure, Trimester and Congenital Anomaly Definitions

The risk of congenital anomalies following first-trimester medication exposure is an important indicator of medication safety during pregnancy. Retrospective cohort studies using routinely collected data are commonly used to assess this risk, yet methodological inconsistencies-such as how cohorts, exposures, timings and outcomes are defined-can compromise reproducibility and validity. This scoping review examined the methodologies used in retrospective cohort studies assessing the association between first-trimester prenatal medication exposure and congenital anomalies.

Citation:
Tan S, Quintrell E, Morgan S, et al. Association Between First-Trimester Medication Exposure in Pregnancy and Congenital Anomalies: A Scoping Review of Cohorts, Exposure, Trimester and Congenital Anomaly Definitions. Pharmacoepidemiol Drug Saf. 2025;34(12).

Keywords:
Congenital anomalies; first trimester; medication; pregnancy; safety

Abstract:
The risk of congenital anomalies following first-trimester medication exposure is an important indicator of medication safety during pregnancy. Retrospective cohort studies using routinely collected data are commonly used to assess this risk, yet methodological inconsistencies-such as how cohorts, exposures, timings and outcomes are defined-can compromise reproducibility and validity. This scoping review examined the methodologies used in retrospective cohort studies assessing the association between first-trimester prenatal medication exposure and congenital anomalies.