The course and outcome of pregnancy in women with nondystrophic myotonias.

Abstract

Nondystrophic myotonias (NDM) are muscle channelopathies characterized by clinical and electrical myotonia. Little is known about pregnancy in NDM. The aim of this work was to assess pregnancy outcomes in women with NDM. In this investigation, we utilized a cross-sectional approach and obtained questionnaire data and medical record review information. Pregnancy outcomes were compared with U.S. national data. Twenty-five women completed the study. There were 63 pregnancies with 53 live births, 8 miscarriages, 4 terminations, and 1 stillbirth. The infertility rate was 28% (above the U.S. average). Fetal distress was reported in 11.7% (U.S. average 3.6%) of the patients. NDM symptoms worsened in 62% of pregnancies. In those who worsened, symptoms usually resolved completely (66%) or partially (32%) after delivery in 2 days to 12 months, the majority (76%) within 3 months. Most pregnancy outcomes were favorable. NDM worsened in nearly two-thirds of pregnancies, but usually improved shortly after delivery. Incidences of infertility and fetal distress were higher than overall U.S. rates.