The Predictive Values of Ductus Venosus Pulsatility Index and ''A Wave'' for Chromosomal Abnormalities

Abstract

The ductus venosus (DV) is a blood vessel in the fetal circulatory system that allows highly oxygenated blood from the umbilical vein to bypass the liver and flow directly to the cerebral and coronary circulation. 1,2 The pressure gradient between the umbilical vein and the right atrium influences the DV, and measurement of DV blood flow can be used as an indirect indicator of fetal cardiac function. [3][4][5] Prenatal ultrasonographic screening markers have become an important tool for detecting congenital anomalies in recent years. 6 First-trimester risk estimation of common chromosomal anomalies is based on a combination of various factors including maternal age, crown-rump length (CRL), fetal nuchal translucency thickness (NT), nasal bone (NB), ma-ternal serum free β human chorionic gonadotropin (fβ-hCG), and pregnancy-associated plasma protein-A (PAPP-A). 7,8 Measurement of ductus venosus blood flow is an optional part of first-trimester screening, but abnormal DV blood flow patterns (such as reversed/absent a-wave pattern or increased pulsatility index for veins) can be integrated into the screening to improve the prediction of chromosomal abnormalities, major congenital heart defects (CHD), and poor pregnancy outcomes. [9][10][11] The most common chromosomal defects detected in the first trimester in the general population are trisomy 21, 18, and 13. 12 Including assessment of ductus venosus flow (abnormal DV "a wave" pattern and/or abnormal ductus venosus pulsatility index) to