Transient neonatal myasthenia gravis: refining risk estimate for infants born to women with myasthenia gravis

J Perinatol. 2021 Sep;41(9):2279-2283. doi: 10.1038/s41372-021-00970-6. Epub 2021 Feb 17.


Objective: Transient neonatal myasthenia gravis (TNMG) can render a neonate vulnerable to catastrophic respiratory depression. Our aim was to describe the clinical manifestations of TNMG, and to determine when the myasthenic signs become apparent in TNMG.

Methods: We reviewed our own experience of infants who underwent routine inpatient monitoring for TNMG and combined our local data with observations from previous studies.

Results: Only three case series (n = 110) reported both the type and timing of onset of myasthenic signs. Adding local data (n = 37) yielded 147 infants born to women with MG. Fifteen infants (10%) developed signs of TNMG with onset being 1.5 ± 2.6 days (mean ± 3SD) after birth. Feeding difficulties and low tone were the commonest presenting signs, and only 1 of the 147 infants needed intubation for hypoventilation.

Conclusions: TNMG signs were mostly not life-threatening. We suggest only 4 days of routine postnatal observation for infants born to women with MG.

MeSH terms

  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Myasthenia Gravis* / diagnosis
  • Myasthenia Gravis, Neonatal* / diagnosis