Pregnancy in multiple sclerosis patients treated with immunomodulators prior to or during part of the pregnancy: a descriptive study in the Spanish population.

OBJECTIVES: To study the management of pregnancy in multiple sclerosis (MS) patients on immunomodulatory therapy (IMT) in routine clinical practice and to analyze pregnancy outcomes and the clinical course of MS around pregnancy.
METHODS: Retrospective, multicentric study in Spain in MS patients receiving IMT before conception and followed for at least three months post-partum.
RESULTS: A total of 1286 medical records were reviewed. Eighty-eight pregnancies were identified in 74 (6%) women, 66% of which were unexposed and 34% exposed pregnancies. In most cases, IMT was discontinued before conception and resumed shortly after delivery. Accidental exposure to IMT did not lead to higher rates of abortions (P = 0.76) or malformations. The relapse rate was decreased during pregnancy (0.31 versus 0.61 in the pre-pregnancy year) and increased after delivery (0.87 on month 3), returning to pre-conception values on month 12. The median EDSS score was not increased during the study.
CONCLUSIONS: Discontinuation of IMT before conception, and resumption shortly after delivery was the most frequent clinical practice procedure. Accidental exposure to IMT did not affect pregnancy outcomes or increased malformation rates. Pregnancy was associated with a reduced relapse rate. No factor was found to predict the risk of relapses during or after pregnancy.