First trimester screening for congenital heart disease

Most obstetrical practices in the United States offer pregnant women at least one ultrasound during pregnancy. This prenatal ultrasound is usually scheduled at around 18 to 20 weeks gestation. Both the American Institute of Ultrasound in Medicine and the American College of Obstetricians and Gynecologists recommend that the four-chamber view be included to screen for congenital heart disease. Recently, many investigators have attempted to screen for congenital heart disease earlier in pregnancy. Fetal nuchal translucency thickness traditionally used to screen for fetal aneuploidy by transvaginal and abdominal ultrasound has also been shown to identify a large proportion of fetuses with congenital heart disease. Recent studies have also reported congenital heart disease in chromosomally normal fetuses with increased nuchal translucency thickness in the first trimester. Advances in ultrasound technology and training over the last 10 years allow greater visualization rates of the four-chamber view and outflow tracks in the late first trimester (up to 90% visualization at 13 weeks). Fetal echocardiography in the first trimester may be indicated for fetuses at risk for congenital heart disease. In this article we present a review of the most recent and ongoing clinical and basic research to support an earlier first trimester approach to diagnosing congenital heart defects.