Ultrasound signs of fetal chromosomal abnormalities at 11–14 weeks of pregnancy and its value in the era of modern genetic testing

Abstract

A steady increase in average maternity age at the time of first childbirth lead to a higher risk of fetal chromosomal abnormalities. The Order No. 1130n of the Ministry of Health of the Russian Federation establish the screening protocol at 11–14 weeks of gestation with assessing the followed criteria of fetal chromosomal pathology: the nuchal translucency thickness, nasal bone measurement, ductus venosus pulsatility index, tricuspid regurgitation, and heart rate. The value of non-invasive prenatal testing (NIPT) in the early prenatal diagnosis of the most common chromosomal abnormalities, as the trisomies 21, 18, 13, and monosomy X is also increasing. Additionally, numerous other fetal karyotype abnormalities can also be suspected at 11–14 weeks of gestation by revealing a number of other ultrasound signs. The article presents the literature review on additional ultrasound signs of various, both more and less common, chromosomal abnormalities. Pathological signs, abnormalities of fetal anatomy and extrafetal structures in the first trimester, which could be used as additional ultrasound signs of chromosomal pathology of various organs and systems (central nervous system and head, heart and blood vessels, urinary system, abdominal organs, fetal skeleton, as well as the placenta, umbilical cord, amniotic membranes) are described in the article. Despite the use of NIPT, including its extended panels, there remains a need to use ultrasound to detect the signs of rarer, but no less significant chromosomal pathologies, such as triploidies, mosaic trisomies, rare autosomal trisomies, duplications, and deletions.