[Neonatal Steinert's disease. Comments on a case and determination of the pregnancy aspects which are predictive of neonatal death].

The authors report a case of antenatal diagnosis which is original in that a maternal illness was discovered that had not been thought of until then. Steinert's myotonic dystrophy can show up in two types after birth, a congenital type and a lethal type. The antenatal diagnosis at present consists in a combination of hydramnios and lack of fetal movements on ultrasound. The obstetrical complications are the threat of premature labour and, often, breech presentation. The method of delivery will depend on how severely the fetus is affected; which is worked out by looking for features of poor prognosis. In the future it will be possible to make an antenatal diagnosis by villus biopsy with the discovery of the responsible gene.