Efficacy, safety and tolerability of dimethylfumarate during pregnancy and breastfeeding

Background The disease course in relapsing-remitting multiple sclerosis (RRMS) is notably affected by pregnancy. Disease-modifying therapies are usually contraindicated during pregnancy and breastfeeding for safety reasons. We assessed safety and tolerability of dimethylfumarate (DMF) in women with RRMS and their infants. Methods We observed 29 pregnancies of 26 women, followed from 2015 to 2020. DMF was administered through week 24 of pregnancy and resumed one month after delivery. We followed mothers with clinical follow-up, MRI and regular ultrasounds to establish the safety and efficacy of DMF during pregnancy and lactation. Infants were monitored up to the third year for infections and developmental disorders. Results No voluntary terminations, ectopic pregnancies, miscarriages or congenital abnormalities were detected. 3 infants (10%) were born preterm. 26 and 3 newborns had an 8/8 and a 7/8 biophysical profile (BPP) score, respectively. During growth, all children resulted between the 70th and 95th percentile for height and weight. Only 1 serious infection was detected in a child. 22/26 mothers decided to breastfeed (interval: 4–7 months). No relapses were observed during pregnancy and during the first 6 months post-delivery. 2 relapses were observed in the 6–12-month interval. New T2 lesions were detected in 3/26 scans at 3 months, 2/26 scans at 12 months, 3/24 scans at 24 months. Conclusion All outcomes related to infant birth and development were comparable to the general population, despite DMF intake during pregnancy. DMF effectively prevented increased disease activity during puerperium. According to our data, continuing therapy while breastfeeding is also safe.