Myasthenic crisis in the puerperium: the possible importance of alpha-fetoprotein. Case report

Increased risk for clinical onset of myasthenia gravis during the postpartum period

OBJECTIVE

To study the risk of clinical onset of myasthenia gravis (MG) in pregnancy and during the first 6 months postpartum because an association between pregnancy or the postpartum period and the onset of autoimmune MG is widely assumed but not proven.

METHODS

The design was a cross-sectional population-based cohort study of 2 MG cohorts (Norway and the Netherlands) with 1,038 healthy controls from Norway. Data were obtained on 246 women with MG (age at onset 15-45 years). Data on pregnancy, hormonal factors, and clinical symptoms were collected by a previously validated environmental MG questionnaire. Relative risk of MG onset before, during, and after pregnancy was calculated by multinomial logistic regression for Norwegian women reaching 45 years of age, adjusted for the observed distribution of person-years in the corresponding control group.

RESULTS

Of the included women with MG, 13 (11.5%) of the Dutch and 24 (18.0%) of the Norwegian patients had their first myasthenia symptoms during the pregnancy or postpartum period. The postpartum period was confirmed to be significantly associated with the onset of symptoms of MG in Norwegian women with MG (relative risk 5.5, 95% confidence interval 2.6-11.6). The risk was highest after the first childbirth.

CONCLUSIONS

Women have a high-risk period for the onset of clinical symptoms of MG in the postpartum period, in particular after the first childbirth. Future studies should aim at elucidating the role of the hormonal-immunological-genetic interaction in the pathogenesis of MG.

Myasthenia gravis and pregnancy

Treatment considerations for women who have MG and are of childbearing age are complicated. When possible, before pregnancy, establishing a plan for therapy is ideal, recognizing the potential concerns for the patient and the fetus. Decisions about treatment during pregnancy must balance the potential complications for the fetus, the patient, and even the integrity of the pregnancy. Most women who have MG are able to complete pregnancy successfully and deliver a healthy baby; however, there always is some risk that NMG may occur. Pregnant patients who have MG are served best at centers capable of providing coordinated expert care from neurologic, obstetric, and pediatric providers.