Pregnancy not linked to increased myasthenia gravis flare-up risk

For female participants with myasthenia gravis, pregnancy is not associated with an increased risk of serious flare-ups of the disease, or new or worsening symptoms, according to a study published May 13, 2026, in Neurology^®, the medical journal of the American Academy of Neurology. For a small percentage of people, the postpartum period of up to a year after birth is associated with an increased risk of serious flare-ups.

Myasthenia gravis is an autoimmune disease that causes muscle weakness. It affects the voluntary muscles. Symptoms can include eyelid drooping, double vision, slurred or low-volume speech, trouble chewing and swallowing, and weakness in the neck, arm and leg muscles.

This is wonderful news for women with myasthenia gravis, as previous small studies had conflicting results and many women choose not to have children due to fear that the disease will get worse during or after pregnancy. It's reassuring to see that pregnancy did not lead to an increase in serious flare-ups and, for the majority of women, that was also true in the months after birth."

Anna Rostedt Punga, MD, PhD, study author, Uppsala University, Sweden

The study looked at whether female participants with myasthenia gravis who were pregnant were admitted to the hospital due to the disease during pregnancy and in the year afterward and compared that with whether or how often they were admitted to the hospital in the year before pregnancy.

Researchers examined a Swedish registry for people with myasthenia gravis. They looked at the records for female participants who had pregnancies that reached at least 22 weeks from 1987 to 2019.

A total of 112 participants with 176 pregnancies were included in the study.

The researchers found that participants were not more likely to be hospitalized for the disease during pregnancy than in the year before pregnancy. For those who did have hospitalizations, there was no increased risk of longer hospitalizations during pregnancy.

For the year after birth, there was overall no increased risk of hospitalization. However, for those who were hospitalized, the length of hospitalization increased compared to the year before pregnancy.

A total of 19 pregnancies, or 11%, in 16 participants required at least one hospital admission for myasthenia gravis in the first year after birth, compared to 12 pregnancies, or 7%, in 11 participants in the year before pregnancy.

After researchers adjusted for other factors that could affect the risk of flare-ups, such as how long participants had the disease, they found that people were five times more likely to have a flare-up in the postpartum period than during the year before pregnancy.

"Nearly 90% of women had no hospital admissions related to myasthenia gravis in their first year after birth," Rostedt Punga said. "For those who did, it's important to note that among the 16 women who needed hospitalization during the postpartum period, nine of them, or more than half, had at least one additional pregnancy where they did not need hospitalization, indicating that these disease exacerbations are not a foregone conclusion."

A limitation of the study is that it looked only at flare-ups that required hospitalization or an increase in medication, so information on milder flare-ups was not captured.

The study was supported by the Erling-Persson Foundation and Region Uppsala.