Two tests flag congenital heart defects. (Nuchal Thickness, Echocardiography).

SAN FRANCISCO--The combination of nuchal thickness measurements and fetal echocardiography can effectively screen for congenital heart defects, according to two studies presented at the annual meeting of the Society for Maternal-Fetal Medicine.

A standardized nuchal thickness measurement and a four-chamber view, both taken on ultrasound at 14-24 weeks' gestation, were independent predictors of congenital heart defects and complemented each other to improve diagnostic accuracy in a study of 1,893 fetuses, Dr. Ray 0. Bahado-Singh reported at the meeting.

Prenatal ultrasound to obtain a four-chamber view of the heart is the most widely used tool for detecting. congenital heart defects, but its sensitivity in the general population is limited, six previous studies have shown.

One 1994 study found a sensitivity as low as 21% when the four-chamber view was used.

In the current study, investigators converted nuchal thickness measurements to multiples of the median and standardized them for biparieral diameter measurement, comparing an individual fetus's measurement to standardized measurements, for a normal fetal group to calculate the individual's risk for heart defects. They compared these. estimations and the estimated risk based on findings from the four-chamber view with actual outcomes.

A review of maternal and pediatric charts showed that 6% of patients had congenital heart defects.

Nuchal thickness measurements were 42% sensitive and 77% specific in detecting congenital heart defects. The four-chamber view was 39% sensitive and99% specific for heart defects, said. Dr. BahadoSingh, director of maternal-fetal medicine and professor of ob.gyn. at the University of Cincinnati.