Patterns of immunosuppressive drug use during pregnancy in women with systemic vasculitis: A nationwide population-based cohort study

Systemic vasculitis (SV) rarely affects women of childbearing age and only small series have been reported to date in pregnant patients. The discovery of an unplanned pregnancy can be an urgent cause for modifying treatments. This study aimed to describe immunosuppressive drugs use before, during and after pregnancy in women with SV.We conducted a cohort study using the French nationwide claims database. We included all women with SV being pregnant between 2013 and 2018. Exposure of interest was defined as exposure to oral systemic or injectable immunosuppressive drug identified using out-hospital reimbursement data and in-hospital reimbursement for expensive drugs.Of 3,246,454 pregnancies, 649 pregnancies were observed in 606 women with SV. Immunosuppressant and glucocorticoids use decreased before pregnancy and then increased after pregnancy (48.4%, 40.7%, 50.4%, respectively before, during, after). Prevalence of glucocorticoids use was broadly stable during pregnancy from 27.9% to 27.6% and 23.7% in the 1st, 2nd and 3rd trimesters, respectively, with a daily dose of about 5 mg. The number of patients treated with non-recommended immunosuppressant during pregnancy gradually decreased before pregnancy and then increased after delivery, whereas proportion of systemic vasculitis flare, estimated from the glucocorticoids daily dose, did not increase significantly during pregnancy.Immunosuppressants and glucocorticoids use decreased before pregnancy and remained stable throughout, suggesting a vasculitis control during this period. Our findings support the importance of pre-conceptional consultations to review medications, and switch not-recommended and teratogenic medications to drugs considered being safe during pregnancy.