EARLY ULTRASOUND DIAGNOSIS OF FETAL CONGENITAL HEART-DEFECTS IN HIGH-RISK AND LOW-RISK PREGNANCIES

Objective: To evaluate the yield of early second-trimester transvagina l ultrasonography in the detection of congenital heart defects among p atients with low or high risk for fetal anomalies. Methods: During 5 y ears, we performed 12,793 transvaginal ultrasound examinations at 12-1 6 weeks' gestation, targeted for detection of fetal congenital anomali es. Three thousand four hundred fifty-three (27%) of these patients we re considered to be at high risk for fetal congenital heart defects (b ecause of family or medical history or teratogen exposure). The other 9340 patients were considered to be at low risk for fetal anomalies. T he four-chamber view and the outflow tracts were evaluated systematica lly in all patients. Results: Congenital heart malformations were obse rved in 47 cases, most of which (29 of 47) were diagnosed in the low-r isk group. Additional extracardiac malformations were observed in 29 ( 62%) of the affected fetuses. Ten of 28 affected pregnancies that were karyotyped (36%) had abnormal chromosomes. Use of the four-chamber vi ew alone would have failed to detect 11 (23%) of the abnormal fetuses. Conclusions: Transvaginal ultrasonography in the early second trimest er is a useful tool for the detection of fetal cardiac structural defe cts, provided that both the four-chamber view and the outflow tracts a re evaluated. When such an anomaly is suspected, additional fetal malf ormations should be sought and fetal karyotype should be determined.