Pregnancy in congenital myasthenic syndrome.

Some case reports have suggested possible worsening of the clinical condition of patients with congenital myasthenic syndromes (CMS) during pregnancy. However, this risk has not yet been quantified in a significant number of patients. Using a standardized report form, we reviewed the gynecological and obstetrical medical history of all patients with CMS listed in the French Registry. The data were reviewed with the assistance of the patients to insure accuracy. We report on 17 pregnancies in eight patients with CMS with mutations in CHRNA1, CHRNE, CHRND, GFPT1, COLQ, or DOK7. Symptoms worsened for six patients during at least one of their pregnancies, and one patient required hospitalization in an intensive care unit during the post-partum period. One patient never recovered to the level of her pre-pregnancy clinical condition. Only one caesarean section was performed. The outcome for children was excellent, with the exceptions of a pulmonary artery atresia in the offspring of a mother on pyridostigmin and a newborn with a severe neonatal congenital myasthenic syndrome (an autosomic dominant slow channel transmission). Our study argues in favor of frequent clinical worsening of symptoms during pregnancy in patients with CMS. These patients should be closely followed by neurologists during the course of pregnancy. However, the overall clinical prognosis is good since the vast majority of patients recovered their pre-pregnancy clinical status six months after the delivery.