The detection rate of first trimester ultrasound in the diagnosis of congenital heart defects: A narrative review

Congenital Heart Defects (CHD) are the most common fetal abnormalities assessed by ultrasound during the second trimester. Improvements in ultrasound technology are allowing more thorough examinations of the fetal heart during the first trimester. The aim of this study was to determine the sensitivity of detecting CHDs during first trimester ultrasound scans. A search for related studies was conducted using MEDLINE, PubMed and Google Scholar databases. A total of n = 16 articles were included in the literature review, combining both retrospective and prospective studies throughout the high-risk, low-risk and unselected populations. An analysis of the studies found the detection rate of CHDs during the first trimester ultrasound scans was 77.5%. The mean sensitivity and the mean specificity across n = 10 articles that provided these values were 78.9% and 90.6% respectively, making CHD detection in the first trimester moderately sensitive and highly specific. This research demonstrates first trimester detection of CHD is possible, however, future research should assess detection rates by non-cardiologists in low-risk populations and should include the gestational age at which each CHD is detected and whether transabdominal or transvaginal approaches were used.