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Prescription Drugs in Pregnancy and Congenital Malformations: A Population-Based Safety Screening Study

Broe A, Pottegård A, Munk-Olsen T, Hallas J, Bliddal M, Petersen I, Damkier P

Pharmacoepidemiology and drug safety, 2025

1,000 participants · 3 citations

Abstract

Background: Counseling women who are either pregnant or contemplating pregnancy on their use of prescribed drugs remains a major clinical challenge. Since the thalidomide tragedy in the 1960s, the use of drugs during pregnancy has been subject to widespread concern due to the potential for unwanted effects on the unborn child, notably major congenital malformations.

Objective: To examine the risk of major congenital malformations following first trimester exposure to all marketed prescription drugs in Denmark.

Study design: This was a population-based cohort study utilizing national health registries in Denmark. We studied all singleton livebirths in Denmark between January 1, 2004, and December 31, 2017, and we linked data from the National Danish Prescription Register, Birth Register, Patient Register, and Cause of Death Register. Using logistic regression analysis, we compared exposed liveborn to unexposed liveborn children while controlling for important confounders. The main outcome measure was major congenital malformations, and the secondary outcomes included organ-specific major congenital malformations as defined by EUROCAT.

Results: Of 326 drugs with at least 5 livebirths with major congenital malformations, 31 were associated with an increased risk of major congenital malformations compared to unexposed livebirths (adjusted Odds Ratio [aOR] ≥ 2.0). Compared to livebirths of women who discontinued treatment prior to pregnancy, 17 drugs with an increased risk (aOR ≥…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 1,000 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

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