Objectives: To study influences of pregnancy on the time-course of myasthenia gravis (MG) and of MG on pregnancy, delivery, postpartum and newborn.
Methods: We retrospectively collected data from 100 women affected with MG, hospitalized between 1994 and 2003 in departments of Neurology of Lille University Hospital.
Results: Eighteen patients had a total of 36 pregnancies, occurring 7.2 years on average after MG onset. MG exacerbation occurred in 7 patients (26 percent) during pregnancy and in 4 (14.8 percent) during postpartum. One patient died of acute respiratory failure during postpartum. Delay between the onset of MG and pregnancy was the only variable significantly associated with MG exacerbation: 5.8 years when exacerbation and 9.5 years when no exacerbation (p=0.03). Seven miscarriages, two therapeutic abortions and no death at birth were reported. Levels of anti-acetylcholine receptor antibodies were abnormal in 3 of 27 newborns (11 percent), but only one (3.7 percent) developed seronegative transient neonatal myasthenia gravis.
Discussion: During pregnancy, the clinical course of MG is variable but exacerbations were associated with a shorter delay between MG diagnosis and pregnancy. The risk of transient neonatal myasthenia gravis is relatively small but exists even when the parturient has stable MG without elevated levels of anti-acetylcholine receptor antibodies.
Conclusion: Our study confirms pregnancy is more difficult to manage at the beginning of MG. Given the unpredictable course of MG during pregnancy, we recommend women affected with MG to begin a pregnancy when the disease is stable.