Reply to the letter of Ebbing EJU-08-2018-2789-LE (Letter to the editor)
12 April 2019 (online)
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.
Several umbilical abnormalities such as single umbilical artery, pathological cord insertion, true umbilical cord knot and umbilical entanglement increase the risk for the fetus. Therefor early detection is very important and may decrease the fetal risk.
There is no doubt that the ultrasound finding of a true umbilical cord knot does automatically impose anxiety on the future mother, but only if there is no sufficient explanation by the examiner, and if there are no sufficient sonographic control examinations. On the other hand, 3 D color Doppler has the chance to demonstrate a false umbilical cord knot precisely that gives relief to the parents-to-be.
In our case the situation for the fetus was even more chancy because we had the rare combination of true umbilical cord knot and single umbilical artery (SUA). We detected the umbilical cord knot with SUA at 21 weeks’ gestation, when the patient was sent to us for a targeted ultrasound examination. There was an extensive counceling of the parents-to-be and the pregnancy was controlled with 2 D/3 D/4 D ultrasound and color Doppler in time intervals of 3 weeks. Fetal growth and blood flow were within normal range until the end of pregnancy. The patient had an uncomplicated vaginal delivery at 40 weeks + 6 days. The female neonate had a weight of 3340 g and was healthy. SUA and true umbilical cord knot were confirmed after the placenta was delivered.