Pregnant women with myasthenia gravis, an uncommon disease that causes muscle weakness, are at an increased risk for complications during delivery.
Researchers from the University of Bergen in Norway, analysed data from the Medical Birth Registry of Norway for 1967 to 2000. Specifically, they compared the 127 births by mothers with myasthenia gravis to the 1.9 million births by mothers without the disorder. According to the researchers, this is the first population-based cohort study where the pregnancies and births of women with myasthenia gravis and conditions in their newborns have been compared to those of an extensive reference group in a time span of more than 30 years.
It was found that nearly 41 percent of myasthenia gravis patients experienced delivery complications, compared with 33 percent of healthy women. The risk of premature rupture of the sac surrounding the baby, a potentially serious problem, was especially high in the myasthenia gravis group - about triple that of other women. These patients were also more likely than other women to require special treatments during birth and were twice as likely to undergo caesarean section. Four percent of infants in the myasthenia gravis group had severe birth defects, which is a higher rate but not statistically different from the percentage in the healthy group - 2 percent.
The results indicate that myasthenia gravis affects both the birth process and the newborn. Future studies need to concentrate on identifying mothers with myasthenia gravis who are particularly at risk to see if special management applied would improve outcome in those cases.
Neurology, November, 2003