Myasthenia gravis in pregnancy: report on 69 cases.

Objective: To review our experience with pregnancies in women with myasthenia gravis (MG).

Study Design: Sixty nine pregnancies among 65 women with MG patients managed by our department over 28 years were included. The course of the disease in pregnancy, mode of delivery and postpartal period were evaluated.

Results: One pregnancy miscarried. In 15% of patients the MG deteriorated in pregnancy a further 16% in the puerperium. 17% of pregnancies were delivered by cesarean section, one due to myasthenia exacerbation. All women with puerperal infections developed exacerbations. One neonatal death, not attributable to myasthenia, was recorded. Transitory neonatal myasthenia gravis (TNMG) was diagnosed in 30% infants. Its incidence was inversely associated with maternal disease duration (P < 0.05). Newborns of thymectomized mothers showed lower rate of neonatal myasthenia compared to those of non-thymectomized women (P < 0.05).

Conclusions: MG patients can have normal pregnancy and delivery but the course is unpredictable. Shorter disease history and infection predispose to puerperal exacerbation. Maternal thymectomy lessens the likelihood of neonatal myasthenia. An interdisciplinary approach is required for managing the pregnant women with MG.