Clinical outcomes during pregnancy and the postpartum period in women with myasthenia gravis and their newborns.

Abstract

Background: Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction associated with increased maternal and fetal risks during pregnancy and the puerperal period.

Objective: To describe the longitudinal course of MG, maternal and neonatal outcomes, and the occurrence of transient neonatal myasthenia gravis (TNMG) from the pregestational period until 12 months postpartum in pregnancies complicated by MG.

Methods: A retrospective, longitudinal case-series study of pregnancies in women with MG who were followed at a single tertiary center for neuromuscular disorders. Disease severity was assessed using the MG Foundation of America Clinical Classification (MGFA)and MG-Activities of Daily Living (MG-ADL) scale. Treatments, delivery mode, postpartum exacerbations, ventilatory support and TNMG in newborns were collected using a standardized proforma. Longitudinal MG-ADL scores were analyzed using generalized estimating equations.

Results: Twenty-four pregnant women with MG were included. Patients had juvenile-onset (n = 12, 50%) or early-onset (n = 12, 50%) MG, which was mostly generalized (n = 20, 83%). Anti-AChR antibodies were positive in 71% (n = 17) and anti-MuSK antibodies in 4% (n = 1). Pyridostigmine was the main therapy; 8% of patients (n = 2) experienced exacerbations during pregnancy. Cesarean delivery occurred in 60% (n = 12), primarily for obstetric indications. The TNMG occurred in 15% of newborns (3 out of 20), and all fully recovered. The MG-ADL scores increased during the first and third trimesters, during the postpartum period, and at 12 months postpartum. Third-trimester MG-ADL scores ≥ 4 were associated with the occurrence of TNMG. No maternal or neonatal deaths occurred.

Conclusion: Pregnancy in MG was characterized by variable disease activity, with late gestation and the postpartum period representing clinically relevant periods of vulnerability to maternal exacerbations and neonatal involvement. Increased third-trimester MG-ADL scores, particularly among antibody-positive mothers, were associated with TNMG and postpartum exacerbations, supporting close monitoring during these periods.