Natalizumab treatment and pregnancy in multiple sclerosis: A reappraisal of maternal and infant outcomes after 6 years.

Objectives: To assess the impact of timing of natalizumab cessation/redosing on long-term maternal and infant outcomes in 72 out of the original 74 pregnancies of the Italian Pregnancy Dataset in multiple sclerosis (MS).

Methods: Maternal outcomes in patients who received natalizumab until conception and restarted the drug within 1 month after delivery ("treatment approach," (TA)) and patients who stopped natalizumab before conception and/or restarted the drug later than 1 month after delivery ("conservative approach," (CA)) were compared through multivariable Cox regression analyses. Pediatric outcomes were assessed through a semi-structured questionnaire.

Results: After a mean follow-up of 6.1 years, CA (hazard ratio (HR) = 4.1, 95% CI 1.6-10.6,  = 0.003) was the only predictor of relapse occurrence. Worsening on the Expanded Disability Status Scale (EDSS) was associated with higher annualized relapse-rate during the follow-up (HR = 3.3, 95% CI 1.4-7.9  = 0.007). We found no major development abnormalities in children.

Discussion: Our data confirm that TA reduces the risk of disease activity; we did not observe an increase in major development abnormalities in the child.