Ultrasound markers of genetic pathology and early hemodynamic changes in human embryo

An increase in the nuchal translucency (NT) by more than 3 mm and ductus venosus reverse blood flow (DVRBF) in pregnancy weeks 11–14 are used as ultrasound markers (UMs) to determine the risk of genetic pathology and/or high probability of heart defects or severe maternal preeclampsia. A pathophysiological explanation for this phenomenon is the development of transient heart failure and increased afterload on the left myocardial ventricle in the embryo in this period. Earlier, it was shown that an increased left ventricular isovolumic relaxation time (LV IRT) reflects an increased systolic arterial pressure in fetal developmental delay. The mean LV IRT measured during an ultrasound study of 122 normally developing human embryos was 30 ± 2 ms. In 27 embryos with an increased NT and DVRBF, the mean LV IRT was 41 ± 3 ms (p < 0.01). This difference confirms the probable increased afterload on human embryo heart in this period of development.