Pregnancy Outcomes in Patients with Congenital Myasthenic Syndromes.

INTRODUCTION/AIMS: The congenital myasthenic syndromes (CMS) are a heterogenous group of inherited disorders that affect neuromuscular junction transmission. Due to their rarity, data on pregnancy outcomes is limited. We sought to explore this in a large CMS cohort attending a national specialty clinic in England. METHODS: All women with CMS who had a documented pregnancy were invited to complete a questionnaire assessing clinical status during pregnancy and post-partum, pregnancy outcomes, foetal outcomes and medication use during pregnancy. RESULTS: Among 16 women with CMS (acetylcholine receptor deficiency {CHRNE}, slow channel syndrome {CHRNA1}, DOK7, RAPSYN and glycosylation {DPAGT1 and GFPT1}), there were 27 pregnancies recorded: 26 single and 1 twin pregnancy. Symptom worsening was reported in 63% of pregnancies, but recovery to baseline function was seen in all but one patient. Miscarriage and Caesarean section occurred in 31% and 33% of women respectively. Over half of patients continued on their medication during pregnancy, which included pyridostigmine (n=10), 3,4-Diaminopyridine (n=9), ephedrine (n=3), salbutamol (n=3) and quinidine (n=1). No foetal malformations were recorded. DISCUSSION: Our results show that clinical worsening during pregnancy is common, but is rarely persistent, and that the majority of women can safely plan pregnancy but need close follow-up by their treating neurology and obstetric teams. Continued medication use should be reviewed on a case by case basis but no safety concerns were identified. This article is protected by copyright. All rights reserved.