From the Guidelines
Myasthenia gravis cannot be diagnosed prenatally in the fetus. This condition is typically diagnosed after birth, when symptoms such as muscle weakness and fatigue become apparent. While maternal myasthenia gravis can affect the fetus through the transplacental passage of antibodies, this does not allow for prenatal diagnosis of the condition in the fetus itself. According to the most recent guidelines, diagnosis and management of myasthenia gravis require the expertise of an experienced neurologist and ophthalmologist, as stated in the adult strabismus preferred practice pattern 1. Some key points to consider include:
- Maternal myasthenia gravis can cause neonatal myasthenia gravis in about 10-20% of babies born to affected mothers, but this is a transient condition that resolves after birth.
- There are no reliable prenatal tests to diagnose myasthenia gravis in the developing fetus.
- Diagnosis typically occurs after symptoms appear, using tests such as acetylcholine receptor antibody testing, repetitive nerve stimulation, single-fiber electromyography, and edrophonium testing, none of which can be performed prenatally.
- Pregnant women with myasthenia gravis should be closely monitored, as the condition can worsen during pregnancy, and their newborns should be observed for signs of muscle weakness after birth.
From the Research
Diagnosis of Myasthenia Gravis
- Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junction, causing muscle weakness and fatigue 2, 3.
- The disease can affect anyone, but it is most common in women between 20 and 40 years old 2.
- MG can be diagnosed through a combination of clinical evaluation, laboratory tests, and electrophysiological studies 4.
Prenatal Diagnosis
- There is no direct evidence to suggest that myasthenia gravis can be diagnosed prenatally 2, 3, 5, 4, 6.
- However, the transplacental passage of antibodies from a mother with MG can result in a neonatal transient disease, known as transient neonatal myasthenia gravis (TNMG) 2, 5, 6.
- TNMG can be diagnosed in newborns through clinical evaluation and laboratory tests, such as the detection of anti-AChR antibodies 5, 6.
Management and Treatment
- The management of MG in pregnancy requires a multidisciplinary approach, involving neurologists, obstetricians, neonatologists, and anesthesiologists 2, 3.
- Treatment of MG in pregnancy includes pyridostigmine and corticosteroids, although the latter have been associated with higher risk of cleft palate, premature rupture of the membranes, and preterm delivery 2.
- TNMG can be treated with acetylcholine-esterase inhibitors and antibody-clearing therapies, such as immunoglobulins, but most children do well with observation only 6.