Heart defects and abnormalities of the great vessels are the most common congenital malformations and they are found in between two and eight of every 1000 pregnancies.1 Ultrasound markers have been increasingly used to detect congenital heart disease (CHD) as early as the first trimester. The best established marker for first-trimester screening, increased nuchal translucency (NT), has been robustly associated with cardiac dysfunction, with or without structural anomalies, in chromosomally normal and abnormal fetuses.2–7 However, increased NT has only modest sensitivity and specificity. Many fetuses with increased NT may have no CHD and may undergo unnecessary detailed cardiac scans. Moreover, some fetuses with CHD and normal karyotype are missed based on NT evaluation alone. Therefore there is interest in assessing whether other ultrasound markers may improve diagnostic discrimination. Abnormal flow in the ductus venosus (DV) has been associated with adverse perinatal outcome,8,9 chromosomal abnormalities10,11 and CHD.12,13 Fetuses with abnormal karyotype have a high incidence of cardiac defects. Conversely, for fetuses with normal karyotype, there are several studies that examine the role of DV waveform abnormalities in the detection of CHD, but the results are variable concerning the ability of this marker to offer discriminating information in fetuses with increased NT and in those with normal NT.
The aim of this study is to evaluate systematically the diagnostic performance of DV waveform in screening for CHD in fetuses with normal karyotype. We analysed the available evidence in an inclusive meta-analysis taking NT measurements into account as well. This allowed us to synthesise information from a substantial number of studies and arrive at more robust and precise estimates of diagnostic performance of the DV waveform in the general population, in fetuses with high NT, and in those with normal NT.