Data for the study was collected from the Medical Birth Registry of Norway, based on compulsory notification of all births in the country. The study included 127 births by women with MG and the 1.9 million births by women without MG.
Women with MG had twice the rate of cesarean section (17.3 percent) when compared to the control group (8.6 percent). Preterm rupture of amniotic membranes occurred three times more often ? or 5.5 percent ? compared to 1.7 percent of the general population.
MG is a chronic autoimmune disease that causes muscle weakness. In people with MG, cells of the immune system make protein antibodies that block nerve impulses to their muscles. The major symptom of MG is muscle weakness that is worsened by fatigue and generally improves with rest. The prevalence of MG is estimated at about 1 in 10,000.
About 15 percent of infants born to women with MG are thought to develop neonatal MG through the passage of MG antibodies between the mother and newborn. The symptoms are usually mild or moderate, and include poor sucking and muscle tone. In this study, neonatal MG occurred in about 4 percent of the newborns, but another 8 percent were observed with MG symptoms following birth.
According to study author Jana Midelfart Hoff, MD, Institute of Neurology, University of Bergen, "Pregnancy does not appear to worsen the long-term effects of MG in women, however the disorder sometimes manifests itself during pregnancy, primarily during the first trimester or shortly after delivery."
Birth defects or other neonatal complications ? from mild to severe ? were noted in 27 of the 127 children born to women with MG. Five of those had severe birth defects, but that number was not considered statistically significant when compared with all births.
Hoff said results of the study shouldn't discourage women with MG from giving birth, but that they should plan to have access to good medical care should complications arise. Neonatal deaths did not rise significantly among MG mothers, nor was there a higher rate of prematurity.
A related Neurology Patient Page on the study, which also provides an in-depth description of Myasthenia Gravis, and its symptoms, diagnosis and treatment options, will be available for downloading at www.neurology.org on November 25.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple sclerosis.
For more information about the American Academy of Neurology, visit its web site at www.aan.com.