Trisomy 18: Fetal ultrasound findings at different gestational ages

The aim of this article is evaluate the sonograhic findings in fetuses with trisomy 18 at different gestational ages. The cases were recruited from pregnant women, who underwent to prenatal diagnosis in the period from October 1995 to September 2006. Seventy-one fetuses with trisomy 18 were diagnosed. On review of the sonograms the majority of these cases had ultrasound anomalies (sensitivity of 91.5%). The most frequent anomalies were abnormalities of extremities (40.8%) and fetal growth restriction (35.2%). More frequently (54.9%) two or more anomalies were present. Nearly all fetuses with trisomy 18 had sonographic abnormalities. Likely improved high-resolution equipment and attention to details by skilled operators led to the detection of most anomalies to trisomy 18. Knowledge of types of specific ultrasound findings can improve prenatal diagnosis in order to provide invasive procedures only when indicated, and to avoid amniocentesis when ultrasound signs are not observed in women at high risk from positive biochemical testing.