Myotonic dystrophy: obstetric and neonatal complications.

Myotonic dystrophy is a relatively common disorder. Since the clinical expression is highly variable, diagnosis is often made only after the birth of an infant with severe congenital myotonic dystrophy. Seven such cases are described. A history of obstetric complications was present in the six multiparous mothers. Neither the neonatal features nor the pregnancy complications are specific, but their combinations should suggest the diagnosis, which can be confirmed by neurologic evaluation of the infant's mother.