Myasthenia gravis is an autoimmune disease of the neuromuscular junction characterized by painless fluctuating skeletal muscle weakness. Disease exacerbations are more likely to occur in the first trimester or puerperium. A number of medications commonly used in obstetric practice can exacerbate the disease. The effect of pregnancy on myasthenia varies substantially from woman to woman and also from pregnancy to pregnancy in the same woman. Mainstay treatments involve acetylcholine esterase inhibitors, corticosteroids and other immunosuppressants, and adequate rest. Newborns may suffer in utero or neonatal consequences, usually transient, of transplacental antibody exposure.