PRENATAL DETECTION OF CONGENITAL HEART-DISEASE BY BASIC ULTRASONOGRAPHY AT A TERTIARY CARE CENTER - WHAT SHOULD OUR EXPECTATIONS BE

Objective: Based upon previous reports, more than 90% of congenital he art defects are believed to be diagnosable when a four-chamber view of the fetal heart is obtained, To determine if this is an accurate stat ement for patients undergoing routine prenatal ultrasonography, we ide ntified all infants or fetuses born with congenital heart disease at o ur institution from 1986 through 1992 who underwent a screening prenat al ultrasound. We determined the sensitivity of a formal screening or basic ultrasound examination to detect a cardiac abnormality. Methods: Each medical record was screened to assess whether the mother underwe nt a prenatal ultrasound examination at 16 or more weeks gestation, wh ether the fetal heart was adequately visualized on that examination to obtain a four-chamber view, and whether a heart defect was diagnosed. We excluded infants with a discharge diagnosis limited to patent duct us arteriosus or atrial septal defect since many of these lesions coul d not be predicted prenatally. Results: Of 103 fetuses or infants with a heart defect other than patent ductus arteriosus or atrial septal d efect, 42 met the criteria for inclusion in the study. Within this gro up, only 38% of the fetuses with defects were identified by the basic prenatal ultrasound. Conclusion: A routine prenatal ultrasound may not be capable of excluding the majority of congenital heart abnormalitie s. Ultrasonographers and pregnant patients alike should be aware that many heart defects may not be identified on a four-chamber view of the fetal heart. Contrary to previous reports, we find that a basic prena tal ultrasound which includes a four-chamber view of the fetal heart i s not a sensitive means to detect congenital heart defects and should not be relied upon to do so.