Are assisted reproductive technology pregnancies more likely to be exposed to teratogenic medication? A whole-population study

Background: Assisted reproductive technology (ART) pregnancies are at greater risk of birth defects than non-ART pregnancies. Teratogenic medication exposure is a potential cause of birth defects that has not been compared between ART and non-ART pregnancies. Aims: To determine whether the prevalence of exposure to teratogenic medicines during pregnancy varies by conception method (ART and three non-ART groups: ovulation induction (OI), subfertile untreated, and fertile naturally conceiving). Materials and Methods: We linked state and commonwealth datasets for all live and stillbirths (≥20 weeks) in Western Australia with a conception date ≥1 July 2012 and date of birth ≤31 December 2014. We calculated the prevalence of exposure to teratogenic medicines (Therapeutic Goods Association Category D/X) across conception groups for the: (i) first trimester, and (ii) second and third trimesters. Results: We identified 2041 ART, 590 OI, 2063 subfertile and 52 987 fertile pregnancies (57 681). The overall prevalence of exposure to Category D/X medicines was 0.8% in the first trimester, and 0.7% in the second and third trimesters. Category X medicines exposure was <0.5% for all conception groups and trimesters. The first trimesters of ART and OI pregnancies were more often exposed to Category D medicines than subfertile and fertile pregnancies, (ART = 4.9%, OI = 2.0% vs subfertile = 1.3%, fertile = 0.6%) as were later trimesters (ART = 3.4%, OI = 1.4% vs subfertile = 0.9%, fertile = 0.6%). Conclusions: The overall prevalence of exposure to teratogenic medicines is low; however, exposure was greatest in pregnancies arising from ART and may be a modest contributing factor to the higher rate of birth defects observed among ART babies.