(8) Prenatal Exposure to Teratogenic Drugs: Contrasts Between Publicly and Privately Insured Persons

Publication Number: 339

Background: Prenatal exposure to teratogenic drugs is prevalent despite evidence supporting fetal harm. Little is known about prenatal exposure to teratogens among publicly insured patients compared to privately insured patients.

Objectives: To compare the top 10 teratogenic drugs with prenatal exposure among publicly and privately insured pregnant persons.

Methods: We used US national 2013 IBM® MarketScan® Commercial Claims Databases and Medicaid Analytic eXtract (MAX) Databases to identify pregnancy episodes among persons aged 12 to 55 years. Since pregnancy outcomes, conception, and pregnancy end dates are not directly recorded in claims data, we adapted previously validated algorithms to define pregnancy endpoints and gestation period. Teratogens were selected from the Teratogen Information System and Clinical Pharmacology based on the risk level and evidence quality. Those with the highest risk level and evidence quality were classified as definite teratogens (140 drugs) and those with possible risk as potential (60). Sex hormones, hormone analogs, abortion, and post-partum hemorrhage treatments were not considered due to challenges separating pregnancy-related indications, nor were opioids (due to complicated risk-benefit) and anti-obesity drugs (mechanism of harm related to weight loss). We defined prenatal exposure based on ≥1 outpatient pharmacy claim or medical encounter for drug administration during relevant pregnancy risk windows. We estimated ratios comparing the prevalence of teratogen exposure per 100,000 pregnancies during versus 90 days before pregnancy to account for background utilization. Ratios below 1 indicate exposure during pregnancy dropped relative to pre-pregnancy use.

Results: The two study cohorts shared 9 definite teratogenic medications among the top 10 most frequently involved in prenatal exposure. Pregnancy/pre-pregnancy exposure prevalence ratios were consistently higher in Medicaid when compared to pregnancies covered by private insurance: 1.2 versus 0.7 for sulfamethoxazole/trimethoprim, 0.7 vs 0.3 for high-dose fluconazole (≥450mg), topiramate 0.7 vs 0.5, lisinopril 0.3 vs 0.2, valproate 0.7 vs 0.7, carbamazepine 1.0 vs 0.8, phenytoin 1.2 vs 0.8, warfarin 0.7 vs 0.6, and losartan 0.4 vs 0.2. Among potential teratogens, drugs with the most frequent prenatal exposures in both cohorts were low-dose fluconazole 3.3 vs 1.3, gabapentin 1.0 vs 0.7, duloxetine 0.9 vs 0.7, and metoprolol 0.9 vs 0.8.

Conclusions: Publicly insured persons have consistently higher risk for prenatal exposure to teratogenic medications when compared to those covered by private insurance, even when accounting for pre-pregnancy utilization. A better understanding of these disparities could lead to improved risk mitigation approaches.