Ultrasonography for guidance of amniocentesis in genetic counseling

The value of preliminary ultrasonography as a guide for amniocentesis in the early second trimester of pregnancy was prospectively evaluated. One hundred and fifty patients were alternately assigned to a control group or to an ultrasound group who underwent examination with a real-time scanner immediately prior to amniocentesis. All amniotic fluid samples were assessed as to the presence of blood by: (1) visual observation during the amniocentesis; (2) appearance of the centrifugate; and (3) microscopic analysis. Ultrasonography did not reduce the failure rate, the incidence of multiple needle insertions, or the proportion of amniotic fluid samples containing blood.