Frequency and risk factors for transient neonatal myasthenia

Abstract

Aim. To determine the frequency and study the risk factors of transient neonatal myasthenia (TNM).Materials and methods. The study included 194 cases of pregnancy in patients with Myasthenia Gravis, observed at the Research Center of Neurology from September, 2015 to January, 2019. For analysis, data from two cohorts were combined: retrospective (151 pregnancies) and prospective (43 pregnancies). TNM was diagnosed in 31 (16%) of newborns. A univariate analysis of the features of maternal myasthenia and the characteristics of newborns in groups with and without TNM was carried out. Student’s t - test and Pearson 2 were used to compare groups. Calculated: odds ratio (OR) and 95% confidence intervals (CI).Results. The risk of TNM is associated with maternal myasthenia with predominantly affected limb and axial muscles (OR 2.62; 95% CI 1.18-5.79), severe maternal myasthenia (IVA-B, V class of MGFA), an unachieved remission before the pregnancy, exacerbations of mother’s myasthenia in the third trimester (OR 4.72; 95% CI 2.09-10.69) and postpartum exacerbations. The average titer of autoantibodies to the acetylcholine receptor (anti-AChR-Abs) before the pregnancy was higher among mothers with a child affected by TNM than without it: 18.32 and 14.35 nmol/l, respectively ( p =0.002). In children with TNM, the mean gestational age and body weight at birth were lower than in children without TNM: 36.7 and38.7 weeks, 2814.8 and 3165.9 g, respectively ( p

Keywords

• transient neonatal myasthenia
• myasthenia gravis
• pregnancy
• risk factors
• transplacental transfer of autoantibodies
• acetylcholine receptor