Course and treatment of myasthenia gravis during pregnancy

Objective: To evaluate the influence of myasthenia gravis (MG) on pregnancy and potential treatment risks for infants and mothers. Background: MG freq uently affects young women in the second and third decades of life, overlap ping with the childbearing years. Knowledge of the potential effects of 1) pregnancy on the course of MG and 2) the use of immunosuppressive drugs dur ing pregnancy is limited, rendering decision-making difficult for both pati ent and physician. Methods: We studied 47 women who became pregnant after t he onset of MG. Immunosuppressive drugs were administered when MG symptoms were not controlled with anticholinesterases. Sixty-four pregnancies result ed in 55 children and 10 abortions. Results: During pregnancy, MG relapsed in 4 of 23 (17%) asymptomatic patients who were not on therapy before conce ption; in patients taking therapy, MG symptoms improved in 12 of 31 pregnan cies (39%), remained unchanged in 13 (42%), and deteriorated in 6 (19%). MG symptoms worsened after delivery in 15 of 54 (28%) pregnancies. Anti-acety lcholine receptor antibody (anti-AChR ab) was positive in 40 of 47 mothers and was assayed in 30 of 55 newborns; 13 were positive and 5 of 55 (9%) sho wed signs of neonatal MG (NMG). All affected babies were seropositive. Conc lusions: Pregnancy does not worsen the long-term outcome of MG. The course of the disease is highly variable and unpredictable during gestation and ca n change in subsequent pregnancies. The occurrence of NMG does not correlat e with either maternal disease severity or anti-AChR antibody titer. Immuno suppressive therapy, plasmapheresis, and TV human immunoglobulins can be ad ministered safely if needed.