Abnormalities of the heart and great arteries are the most common congenital defects, accounting for about 20% of all stillbirths and 30% of neonatal deaths due to congenital defects . Although most major cardiac defects are amenable to prenatal diagnosis by specialist fetal echocardiography, routine ultrasound screening in pregnancy fails to identify the majority of affected fetuses. Consequently, effective population-based prenatal diagnosis necessitates improved methods of identifying the high-risk group for referral to specialists. The traditional method of screening for cardiac defects, which relies on family history of cardiac defects, maternal history of diabetes mellitus and maternal exposure to teratogens, identifies only about 10% of affected fetuses . A major improvement in screening for cardiac defects came with the realization that the risk for cardiac defects increases with fetal NT thickness and is also increased in those with abnormal flow in the ductus venosus and across the tricuspid valve. Reversed a-wave in the ductus venosus or tricuspid regurgitation, observed in about 2 and 1%, respectively, of normal fetuses is found in 30% of affected fetuses. Specialist fetal echocardiography for cases with NT above the 99th centile and those with reversed a-wave in the ductus venosus or tricuspid regurgitation, irrespective of NT, would require cardiac scanning in about 4% of the population and would detect about 50% of major cardiac defects.

Author: Ultrahelikeskus

Duration: 120

Published: 2011-10-01 08:39:24

Screening for cardiac defects.avi