Rapid karyotyping in fetuses with abnormal sonogram.

Prenatal karyotyping of fetuses having an abnormal sonogram was undertaken in 27 pregnancies between 17 and 39 weeks, using fetal blood obtained by percutaneous umbilical cord blood sampling under ultrasound guidance. Eight chromosomal abnormalities (29.7%) were detected, including 45, X (2 cases), trisomy 21(1 case), 46, XY,-13,+t(13,13) (1 case), 47, XX,+18(3 cases), 47, XXY (1 case). Nineteen fetuses had a normal karyotype (46,XX:9 cases, 46,XY:10 cases). The fetal karyotype was available within 72 h and fetal management was planned accordingly. We concluded that in fetuses with an abnormal sonogram, rapid karyotyping using fetal blood obtained under ultrasound guidance had important implications in obstetric and neonatal management and would facilitate genetic counselling.