There is another, much rarer type of myasthenia gravis that is not acquired, but genetic.
Women with acquired myasthenia gravis won't pass the disease itself on to their children
, but since the myasthnia antibodies made by mom can cross the placenta
into the circulation of the fetus, the fetus can be affected temporarily (mom's antibodies can stay in the baby up to several weeks after birth). This condition is called neonatal myasthenia gravis. Newborns with neonatal myasthenia can have temporary weakness of limb muscles, breathing muscles, and feeding muscles. They can also have a condition called arthrogryposis
, stiff joints with limited range of flexibility because they didn't move as much in the womb as they might have otherwise.
This is why it is important to have acquired myasthenia gravis well-controlled throughout pregnancy
. There are many different kinds of medications used to control myasthenia. Some of them, particularly the immunosuppressants (like methotrexate
, mycophenolate mofetic) are known to cause harm to the baby if taken during pregancy, while breastfeeding
, or even prior to conception. Other treatments such as steroids
and ivig are less risky (but not zero risk).
Women with myasthenia who are considering pregnancy should work very closely with a team including a neurologist experienced in the treatment of myasthenia gravis, an obstetrician and a neonatologist. This is the best way to reduce worry, and risk, as much as possible.
For general information about myasthenia gravis, visit the myasthenia gravis foundation of america website at www.Myasthenia.Org.