The role of second-trimester ultrasonography in pregnancies at high risk for fetal chromosome anomalies

Aim To assess the value of sonographic markers for aneuploidies detected during a second trimester ultrasound examination among a population of high risk pregnant women. To evaluate if a mid trimester "genetic" sonogram can be offered to these women in the counseling before a genetic invasive procedure. Material and methods A retrospective study of 462 high risk pregnant women, including 6 twin pregnancies. Between January 1, 1997 and December 31, 1998, a detailed sonogram was performed, in the same day, prior an invasive genetic prenatal diagnosis (452 amniocentesis and 12 cordocentesis). Results Of the 462 patients, 2 needed both amniocentesis and cordocentesis. 431 fetuses (92.9%) had a normal karyotype; 17 (3.7%) had abnormal karyotype (including 5 with trisomy 21); 14 (3%) had minor variants and in 2 cases a genic disease was diagnosed. In 30 fetuses (6.5%) one or more sonographic markers were detected, including 3 (60%) out 5 fetuses with trisomy 21.