Interim Analysis of Pregnancy Outcomes After Exposure to Dimethyl Fumarate in a Prospective International Registry.

Background and objectives: Oral delayed-release dimethyl fumarate (DMF) is not recommended during pregnancy and should only be used if the potential benefit justifies the potential fetal risk. Although DMF was well tolerated in clinical trials with consistent safety results in postmarketing surveillance, data are limited in pregnant women. The objective was to provide pregnancy outcomes and DMF exposure information from an interim analysis from a prospective, international registry (TecGistry; NCT01911767).

Methods: Women exposed to DMF from the first day of their last menstrual period before conception or during pregnancy were evaluated. Data were obtained at enrollment; 6-7 months' gestation; 4 weeks after estimated due date; and 4, 12, and 52 weeks after birth. Outcomes included live births, gestational size, pregnancy loss, birth defects, and infant or maternal death after delivery. Outcomes were analyzed cumulatively from October 30, 2013 (the start of TecGistry), to April 8, 2020.

Results: Of 345 enrolled patients, median (range) age was 32 (20-43) years. The mean (SD) duration of gestational weeks of DMF exposure was 4.9 (3.8). Most infants were full-term at birth (n = 249/274; 91%) and of average gestational size (n = 190/232; 82%). Of 351 outcomes, 277 were live births; 17 (5%) spontaneous abortions (95% confidence interval [CI] 2.6%-7.1%), including 1 (<1%) molar and 1 (<1%) ectopic pregnancy, were reported. There were 8 (2.9% [95% CI 1.3%-5.6%]) adjudicator-confirmed birth defects among the 277 live births.

Discussion: Interim results from this large registry indicate that early DMF exposure was not significantly associated with adverse pregnancy outcomes. Outcomes are consistent with previous smaller reports and with the general population.

Trial registration information: TecGistry; clinical trial registration number: NCT01911767.