Disease Course, Outcomes, and Complications in Pregnant and Breastfeeding Women with Multiple Sclerosis Treated with Rituximab or Ocrelizumab: A Narrative Review.

Multiple sclerosis (MS) predominantly affects women of childbearing age, and decision-making regarding disease-modifying therapies during pregnancy and lactation, particularly for highly effective anti-CD20 therapies such as rituximab and ocrelizumab, remains challenging. This review aims to synthesize available evidence on the course of MS, pregnancy, and neonatal outcomes, complications, and safety considerations in pregnant and breastfeeding women with MS exposed to rituximab or ocrelizumab. This structured narrative review was conducted in accordance with the PRISMA reporting framework. A systematic search of major scientific databases was performed for studies published between 2000 and 2026. Included study designs comprised cohorts, registries, case series, case reports, and systematic reviews. Data were extracted based on exposure type (preconception, during pregnancy, postpartum, and during breastfeeding) and key outcomes (relapse and disease activity, live birth, miscarriage, preterm delivery, congenital anomalies, infections, and neonatal immune parameters) and were narratively synthesized. The body of evidence indicates that exposure to rituximab or ocrelizumab, particularly when treatment was administered prior to pregnancy and conception occurred at an interval from the last dose, is often associated with better disease stability during pregnancy and a reduced risk of postpartum relapse. Most reports have not identified a consistent pattern of increased major congenital anomalies, and pregnancy outcomes have generally fallen within expected ranges. The most important neonatal consideration is transient B-cell lymphopenia in some exposures occurring close to late pregnancy; this finding has usually been reported as reversible and requires attention to the timing of live vaccinations. During breastfeeding, existing evidence supports minimal drug transfer into breast milk and the absence of clinically meaningful adverse outcomes in infants. Current evidence suggests that rituximab and ocrelizumab may be considered as strategies for disease control around pregnancy and in the postpartum period in women with active MS. However, decision-making should be individualized, based on disease severity, timing of exposure, maternal benefit, and neonatal monitoring considerations. Prospective studies and expanded pregnancy registries are needed to better evaluate long-term maternal and infant outcomes.