Early diagnosis of severe congenital malformations by ultrasonography.

The significance of ultrasound examinations in early stages of pregnancy is illustrated by the detection of four severe congenital malformations within the first trimester and one malformation syndrome within the first part of the second trimester of pregnancy. We report on the diagnosis of a fetal POTTER syndrome (13 weeks), an anencephalic fetus (13 weeks), MECKEL-GRUBER syndrome (16 weeks), fetal exomphalos (12 weeks) and finally "Siamese twins" (11 weeks). Characteristic ultrasonographic findings are presented and described in detail. The incidence of these severe fetal abnormalities vary between 1:1000 (anencephaly), 1:6000 (exomphalos), 3:10,000 (POTTER-Syndrome), 1:50,000 (MECKEL-GRUBER Syndrome) and 1:250,000 (conjoined twins) live births. The sonographical diagnosis of all these malformation syndromes could be established by thorough and repeated inspection of the fetal head and fetal body with longitudinal and transversal scans. It is concluded, that the high and still increasing reliability congenital structural anomalies renders routine systemic ultrasound screening an attractive possibility already at this "early" stage of pregnancy.