Maternal myasthenia gravis complicated by fetal arthrogryposis multiplex congenita

We report the management of a 24-year-old primigravid woman who was diagnosed with myasthenia gravis at 20 weeks of gestation. Maternal symptoms improved with therapeutic plasma exchange, steroids, immunoglobulin therapy and pyridostigmine. Despite this, the fetus had arthrogryposis multiplex congenita due to trans-placental transfer of anti-acetylcholine receptor antibodies. The baby was delivered by elective caesarean section at 34 weeks of gestation but died in the immediate postpartum period. The mother underwent thymectomy within five weeks of delivery. The implications of myasthenia gravis for both the mother and baby are discussed.