To neurologists, pregnancy and delivery are major issues in patients with neuroimmunological diseases such as multiple sclerosis (MS), neuromyelitis optica (NMO), and myasthenia gravis (MG).
The Pregnancy in Multiple Sclerosis Study reported that the annual relapse rate (ARR) decreases during pregnancy and increases during the first trimester after delivery. Discontinuation of interferon-β (IFNβ) is usually recommended prior to pregnancy. IFNβ exposure is related to lower birth weight, but no fetal complications or development abnormalities have been reported.
Regarding pregnancy in NMO, our current study showed that the ARR during pregnancy was same as before pregnancy. A higher ARR was noted after delivery than in patients with MS. The numerous cases of NMO with onset after pregnancy suggest that delivery affects the exacerbation or of NMO.
In women with MG, exacerbations occurred during approximately 30% of pregnancies, remission occurred in 30%, and 30% experienced no change. Exacerbations occurred in the first trimester and the three months postpartum. We must consider the risk of transient neonatal MG, because the frequency is 10-20% in infants born of MG mothers. It is especially important to carefully consider anti-MuSK antibody-positive patients because bulbar palsy is a major symptom.