Management of Myasthenia Gravis in Pregnancy

Myasthenia gravis is an autoimmune disorder characterized by fluctuating weakness of extraocular and proximal limb muscles. It occurs in 1 in 5000 in the overall population and is 2 times more common in women than men. The onset in women is most common in the third decade, and risk of severe exacerbation occurs most frequently in the year after presentation. The disease does not have an impact on fertility and overlap with pregnancy is expected. This article provides a description of the disease process and its impact on the expecting mother, fetus, and newborn. Management options in pregnancy and lactation are discussed.

Maternal myasthenia gravis: a cause for arthrogryposis multiplex congenita

BACKGROUND

Arthrogryposis multiplex congenita (AMC) is a condition defined as contractures in more than two joints and in multiple body areas. The principal mechanism leading to the development of AMC in utero is decreased fetal movement.

OBJECTIVE

Both fetal and maternal factors can lead to this condition, including maternal myasthenia gravis (MG) which is the topic of this review. MG is an autoimmune disease in which antibodies (immunoglobulin G) are formed against acetylcholine receptors. The disease can affect both genders, but women are more prone to develop the disease in early adulthood, a phase of life when the focus of many women is often directed towards founding a family. During pregnancy, maternal antibodies are transmitted to the fetus.

RESULTS

Although the child is unaffected in most cases, the constant transmission of antibodies in utero can lead to neonatal myasthenia post-partum, a transient condition characterized by hypotonia and swallowing/respiratory difficulties as well as AMC.

CONCLUSION

The maternal antibody profile in mothers with MG seems to play a key role in whether the child develops AMC or not. There are also indications that there may be a relation between neonatal MG and AMC, as well as a high recurrence rate in siblings.