Use and safety of disease-modifying therapy in pregnant women with multiple sclerosis

Purpose: The purpose of this study is to describe dispensing patterns and comparative safety of disease-modifying therapies (DMTs) during pregnancy in women with multiple sclerosis (MS). Methods: We identified pregnancies from the Truven Health Marketscan (R) Commercial Claims and Encounters Database (2011-2015) and ascertained MS before delivery from inpatient and outpatient claims. We computed the proportion of women with DMT dispensing claims around pregnancy and estimated risk ratios of spontaneous abortion, infections, cesarean section, preterm delivery, poor fetal growth, preeclampsia, and major structural malformations by DMT exposure. Results: Of 984058 pregnancies, 1649 were to women with MS. Thirty-five percent of women with MS filled a prescription for a DMT in the 90days before pregnancy. DMT use declined during pregnancy but increased again after delivery. Glatiramer acetate and interferon beta were most commonly dispensed. Pregnancies with and without early DMT exposure had similar risks of outcomes to one another and to pregnancies in women without MS. Small numbers did not allow evaluation of specific DMTs. Conclusions: Approximately one third of commercially insured women with MS in the United States uses DMTs before conception. Neither MS itself nor early pregnancy use of DMTs overall seems to be associated with a substantial risk of adverse pregnancy outcomes.