Diagnosis of Fetal Abnormalities during the First Trimester

Abstract

The quality of prenatal diagnosis of fetal abnormalities has advanced with improved resolution of ultrasound imaging and cytogenetic/molecular analysis. In this article, we briefly review the history of diagnosing fetal abnormalities and the current status of prenatal diagnosis during the first trimester (up to the first 14 weeks' gestation), focusing especially on fetal malformations and chromosomal abnormalities. As for detectable morphological abnormalities, roughly half of all major structural anomalies including those in the central nervous system, cardiovascular system and gastrointestinal system can be detected, if not definitely diagnosed. For screening of chromosomal abnormalities, especially for trisomy 21, ultrasound soft markers such as increased nuchal translucency, maternal serum markers and their combinations have been implemented. More recently, non-invasive prenatal testing, by analyzing cell-free DNA in maternal serum, is now available to detect chromosomal abnormalities with higher predictability. Although invasive chorionic villus sampling offers definite diagnosis for chromosomal abnormalities during the first trimester, non-invasive diagnostic techniques are patient-friendly and promising in the future perspectives on prenatal diagnosis for chromosomal abnormalities.

The role of ultrasound in first-trimester screening after the introduction of NIPT as a service of public health insurance – a consensus statement of the Fetal Medicine Foundation (FMF) Germany

“…Ultrasound allows early detection of many structural fetal defects [12,13,14,15,16] (see ▶ Table 3).…”

Pruebas de screening prenatal para la detección temprana de cromosomopatías

“…3, pp. 132 -152 julio -septiembre 2023 www.anatomiadigital.org trisomías, así como con malformaciones estructurales, como las anomalías cardíacas (2,23,24).…”

“…Sin embargo, en el cribado combinado del segundo trimestre realizado en la semana 16, se encontró una concentración elevada de alfafetoproteína. Esto podría indicar defectos en el tubo neural del feto, como anencefalia o espina bífida (23).…”

Body stalk anomaly complicated by complex congenital heart disease: first-trimester ultrasonic diagnosis and fetal autopsy

“…The quality of prenatal diagnosis of fetal abnormalities has advanced with improved resolution of ultrasound images. A scan of the fetal anatomy in the rst trimester allows for the detection of approximately half of all major structural anomalies, including those of the central nervous system, cardiovascular system, and gastrointestinal system [7,8]. cc-TGA is a rare congenital cardiac anomaly constituting less than 1% of all CHDs [9] and is associated with discordant atrioventricular and ventriculoarterial connections.…”