The Value of Ultrasound in Diagnosing Umbilical Cord Knot and Its Effect
on Fetal Perinatal Outcome
Abstract
Objective:To analyse the prenatal diagnostic value of ultrasound in
umbilical cord knot(UCK) and the correlation of UCK and fetal perinatal
outcome.Methods:Firstly, retrospective analysis was conducted on the
prenatal ultrasound and clinical data of newborns or induced fetuses
with UCK.Secondly,the incidence of UCK and its relationship with fetal
perinatal outcome were summarized and analyzed.Then,the value and image
characteristics of prenatal ultrasound in diagnosing UCK were
analyzed.Finally,fetuses who were diagnosed as UCK after delivery were
UCK group, and control group was 200 cases randomly selected from other
normal fetuses.The differences of ultrasonic parameters and related
clinical parameters were compared.Results:During 5 years, there were
40346 fetuses were born, including 209 cases stillbirths in the third
trimester.99 fetuses were confirmed with UCK by postnatal diagnosis
(including 3 stillbirths died of UCK),accounting for 3% of the
diagnosis of UCK.2D ultrasonic images can be classified as excessively
distorted, stacked or cloverleaf.The 3D-US can clearly identify the true
and false UCK,which can be divided into loose UCK,tight UCK,spiraling
umbilical cord and twisted and stacked umbilical cord.RI of middle
cerebral artery in UCK group was lower than that in normal control group
(P<0.05).There were statistically significant differences in
maternal age, multiparty, gestational weeks, gestational diabetes
mellitus, amniotic fluid volume and length of umbilical
cord.Conclusions:The incidence of UCK is only 0.25%, but mortality
accounts for 1.4% of fetal death in the third trimester.2D-US is
combined with 3D-US can improve prenatal diagnostic accuracy of UCK.With
maternal age,parity,amniotic fluid volume and cord length increased,the
risk of UCK is increased.