Midtrimester genetic amniocentesis. Use of ultrasound direction vs. blind needle insertion.

A prospective comparison of ultrasound-directed second-trimester genetic amniocentesis to blind amniocentesis showed a significant reduction in the incidence of both bloody taps and failed amniocentesis. The incidence of other parameters, such as fetal outcome, failed culture of amniotic fluid fibroblasts and spontaneous abortion, was similar. These data support the use of amniocentesis under ultrasound control as a routine component of prenatal genetic diagnosis.