Reply to the letter of Ebbing

Dear Dr. Ebbing:

We are thankful for your important comments on the subject of true umbilical cord knots. In deed the umbilical cord is not always a well observed anatomical structure during the ultrasound examination. Most of the operators pay only attention to the number of umbilical vessels and placental cord insertion. Using color Doppler, umbilical entanglement and/or a true umbilical cord knot can be detected with 2 D ultrasound. However, 2D ultrasound provides the operator only with single anatomical section planes, while 3 D ultrasound enables a spatial demonstration of the umbilical cord, allowing a much better demonstration of umbilical cord abnormalities.