Myotonic dystrophy and pregnancy. A report of two cases and a review of the literature.

Myotonic dystrophy is a rare disease (1/8000), that is rarely associated with pregnancy, due to the fact that parents carrying the disease often encounter hypogonadism. Myotonic dystrophy is a neuro-endocrinian 'heredo-degenerative' dystrophy, with dominant autosomic transmission. Its association with pregnancy can lead to several problems. The myotony is often aggravated which leads to obstetrical complications turning into fetal loss, premature term delivery, hydrops, in-utero death, difficulties in expulsion, haemorrhage during delivery and/or anaesthetic accidents. The following signs during the pregnancy can diagnose fetal damage: presence of a hydrops, rare active fetal movements, and low fetal cardiac rhythm. They signify serious fetal damage leading to a diagnosis of myotonic dystrophy. Personal and family antecedents as well as an important hypotony and respiratory distress discovered in the new born are equally evocative elements. In congenital cases (6-30% of the time) the prognosis of the child is pessimistic. For all of the above elements, transmission is of maternal origin. The diagnosis of the congenital form is difficult because the disease is often unknown by the mother. The appearance of molecular tools permits a diagnosis to be formed much more rapidly in a new-born suspected to carry the illness of neonatal Steinert. Two observations illustrate this pathology. The occurrence of congenital myotonic dystrophy in a new-born allows us to diagnose the disease within the mother.