Color Doppler assessment of implantation and early placentation

Vascular factors are essential for proper implantation and placentation. Th erefore, Doppler assessment is of prime importance in the clinical evaluati on of these processes. Doppler of the uterine and spiral arteries is a good predictor of uterine receptivity prior to embryo transfer. Perifollicular blood flow can determine the number and maturity of the oocytes, as well as the likelihood of pregnancy. By combining several ultrasound variables and Doppler scores, a good clinical prediction for the likelihood of achieving pregnancy after assisted reproduction can be obtained. Color Doppler facil itates the evaluation of uteroplacental, fetoplacental and intervillous cir culation. The uteroplacental arteries can be seen as a 'color comet' at 4.5 weeks of pregnancy. Yolk sac and umbilical circulation are easily recorded from the 6th week when heart beats are detected. From this moment, color D oppler can also detect a venous flow signal within the chorion, demonstrati ng the beginning of the fetomaternal exchanges in the intervillous space.