Routine Sonography of Fetal Heart Advocated.

MARINA DEL REY, CALIF. -- Sono graphic evaluation of the fetal heart should be part of every routine fetal examination after 18 weeks' gestation when a fairly complete image can help diagnose cardiac abnormalities, Dr. Beryl R. Benacerraf said at a conference on ultrasound and women's health.

Such an exam can help identify structural heart defects, evaluate arrhythmias, assess ventricular function, and flag possible chromosomal abnormalities such as trisomies 21, 18, and 13, which have a strong association with congenital heart anomalies, according to Dr. Benacerraf, professor of ob.gyn. and radiology at Harvard Medical School, Boston.

"The hardest ultrasound examination to do," fetal echocardiography, has been shown to be equally effective in detecting abnormalities in low- and high-risk patients, she said at the conference sponsored by the American Institute of Ultra sound in Medicine.

Indications for a fetal echocardiogram include a family history of congenital heart defects, poorly controlled diabetes, maternal drug use of lithium or anticon vulsants, maternal alcohol use, or a known chromosomal anomaly.

Echocardiography can detect abnormalities in blood flow, such as regurgitation and reverse flow into the aortic root from the ductus arteriosus, which could indicate complete obstruction or a hypoplastic left heart.

Sonographic examination of the fetal heart should not be limited to those at high risk for such disorders, said Dr. Benacerraf, who studied 69 fetuses with con genital heart disease whose mothers had undergone prenatal sonography at 18 weeks or later.

At the time of referral for sonography, 39 of the fetuses had been diagnosed as high risk and 30 as low risk for cardiac disorders.