OBSERVATIONS ON PREGNANCY IN PATIENTS WITH MULTIPLE SCLEROSIS RECEIVING DISEASE-MODIFYING THERAPY AT THE SECOND STAGE: A SINGLE-CENTER CASE SERIES

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that predominantly affects women of reproductive age. Data on the safety of second-linedisease-modifying therapies (DMTs) during pregnancy remain limited. This study aimed to evaluate pregnancy outcomes in MS patients exposed to second-line DMTs.
MS patients who became pregnant while receiving second-line DMTs and were followed at the neurology outpatient clinics of our hospital between 2024 and 2025 were retrospectively evaluated. Pregnancy losses occurring prior to DMT exposure were excluded. Demographic characteristics, MS-related clinical data, treatment history, and pregnancy outcomes were obtained from electronic medical records and phone calls.
Seven pregnant women were included, with a median age of 35 years (range: 24–40). MS diagnosis years ranged from 2011 to 2019, and the mean duration of second-line DMT use was 4.6 ± 2.0 years. Natalizumab treatment was continued through out pregnancy in three cases, all resulting in term live births without major congenital anomalies, including one twin pregnancy. Three pregnancies occurred 3–6 months after ocrelizumab exposure; one was electively terminated at 7–8 weeks of gestation, while two are ongoing without complications. One pregnancy resulted in spontaneous abortus at 9 weeks during cladribine exposure.
Natalizumab exposure during pregnancy was not associated with adverse pregnancy outcomes in this study. The spontaneous abortus observed after cladribine exposure correlates with the limited available evidence. Pregnancy outcomes following ocrelizumab exposure remain uncertain. These results underline the importance of preconception counseling, individualized treatment planning, and multidisciplinary MS monitoring in reproductive-age women.