Despite the rapid technological advance, the expansion of prenatal ultrasound diagnosis, as well as the
accumulation of experience by both domestic and foreign experts, prenatal recognition of true knots of the
umbilical cord causes significant difficulties. Three cases of successful ultrasound diagnosis of true knots of the
umbilical cord and brief review of the literature are presented.
Clinical value of color doppler ultrasound in prenatal diagnosis of umbilical cord entry abnormity