SAN DIEGO (FRONTLINE MEDICAL NEWS) – A majority of U.S. teenage girls on Medicaid who were prescribed teratogenic medications for rheumatic diseases did not receive or fill prescriptions for contraception, and some became pregnant while taking the medication, a study showed.

The analysis of a Medicaid database of paid claims from 12 unidentified U.S. states during 2013-2015 found a pregnancy rate of 7.6% in 4,853 females aged 15-19 who were prescribed at least one of eight teratogenic medications, mostly labeled as category D or X: cyclophosphamide, enalapril, leflunomide, lisinopril, losartan, methotrexate, mycophenolate, and cyclosporine (category C). This rate varied from 2.2% in 15-year-olds to 13.6% in 19-year-olds.

In the sample, 53% received a prescription contraception at any time during the 3-year study period, but only 25% who became pregnant had received a contraception prescription prior to becoming pregnant, lead study author Kimberly Hays, MD, said at the annual meeting of the American College of Rheumatology.

The number of filled prescriptions for contraception was low despite the associated risk of the teratogenic medications, said Dr. Hays, a third-year pediatric rheumatology fellow at the Medical University of South Carolina in Charleston.

“Each teratogenic medication carries a different risk,” she said. “Certain teratogenic medications carry a greater risk than other teratogenic medications. The associated risk may vary based on the timing and duration of use.”

“The risks and benefits of using a teratogenic medication for treatment should be discussed with teens and women of reproductive age,” Dr. Hays said. “Disease activity should be low, and the teratogenic medication should be replaced with a safer medication prior to pregnancy if one is available. Highly effective forms of contraception should be offered to patients who are at risk for unintended pregnancy and those who are not trying to conceive.”

In addition to rheumatic diseases, the eight teratogenic medications cited in the study are used to treat other conditions such as inflammatory bowel disease, hypertension, kidney disease, and malignancy, Dr. Hays said.

The study population was made up of 45.0% whites, 36.6% blacks, 4.8% Hispanics, and 13.6% others.

About 10% were defined as having a specific rheumatic disease, mainly systemic lupus erythematosus (70%), Dr. Hays said. “However, more than 10% had a rheumatic condition of some kind. Generalizations in ICD-9 coding made it difficult to identify specific diseases in some cases.”

The study did not examine birth defect outcomes in the babies born to the females in the cohort, but Dr. Hays said researchers are considering whether to track these numbers via claims data. The study also was not able to capture the use of nonprescribed contraception, such as condoms.

Moving forward, Dr. Hays said the researchers “are planning to also look at pregnancy and contraception rates in age-matched teens not taking teratogenic medications using the same Medicaid claims database. We are also hoping to research patient and provider perspectives pertaining to teratogenic medication use/risk and contraception.”

In addition, researchers hope to examine how commonly the individual drugs were prescribed and link them to contraception use and pregnancy, she said.

The study authors had no relevant financial disclosures, and the study had no external funding. The Medical University of South Carolina provided funding for database access.

SOURCE: Hays K et al. ACR 2017 Abstract 1813 .