First-trimester Doppler ultrasound examination.

First-trimester screening is focused on both markers of aneuploidies and structural abnormalities detection. In the past ten years, clinicians have been increasingly interested in using Doppler ultrasound in the first trimester of pregnancy. Doppler examination can help estimate the risk of aneuploidy and early diagnose severe fetal malformations. The purpose of this article is to highlight the importance of color Doppler ultrasound examination of the fetus in the first trimester. Color Doppler examination also has a great significance in studying maternal-fetal circulation. According to the ISUOG guidelines, several vascular territories should be covered: uterine arteries, umbilical artery, and ductus venosus. The nowadays first trimester Doppler examination not only identifies specific ultrasonographic markers for aneuploidy but also aids in the identification and analysis of many anatomical structures. [ABSTRACT FROM AUTHOR]