Multiple True Umbilical Knots: A Silent Risk for Intrauterine Growth Restriction with Anomalous Hemodynamic Pattern

Abstract

True knots of the umbilical cord can represent a serious complication for the fetus due to the possible alteration in the fetal circulation with consequent intrauterine growth restriction or fetal death. We report a case of 5 true umbilical cord knots associated with severe fetal growth restriction and an abnormal hemodynamic pattern. The Doppler examination showed a hemodynamic pattern characterized by an early alteration in the waveform profile in the fetal venous districts with normal impedance to flow values in both uterine and umbilical arteries. This normal profile of the umbilical arteries remained unchanged until the last stage of hemodynamic decompensation, while the profiles of the uterine arteries remained normal until delivery. This case report suggests that it is important to pay close attention to the evaluation of the fetal cord in situations in which the above described hemodynamic pattern is noted. Although the ultrasound diagnosis of true knots is extremely difficult, the presence of a true knot should always be suspected in the presence of an intrauterine growth restriction fetus when the venous district is altered before the fetal arterial districts after exclusion of other detectable reasons for growth restriction.

Ultrasound Evaluation of the Amount of Wharton’s Jelly and the Umbilical Coiling Index

“…Predanic et al [23] suggested that HCC could be rather more prone to cord torsion than to compression or stretching that would adversely affect blood flow, such as in the experimental model that demonstrated that less encirclement force was required to occlude venous perfusion in cords that had more coils [24] . In these respects, the umbilical Doppler changes described by Predanic et al [23] would be similar to those reported for cases with true knots of the umbilical cord [25] . Therefore, in cases with HCC various complications would frequently occur during labor probably due to a smaller amount of WJ.…”

Four‐dimensional and Doppler sonography in the diagnosis and surveillance of a true cord knot

“…Despite the relatively high incidence of true knots of the umbilical cord at birth and the increased risk of stillbirth,2, 4 a prenatal diagnosis is infrequently reported 3. Different sonographic findings have been proposed as characteristic of true knots, although none of them has been reported to be specific for the diagnosis 5.…”

“…Once the prenatal diagnosis of a true knot is highly suspected, the management of the case has to be prudent, given the increased risk of intrauterine fetal demise,1, 2 and adequate counseling has to be offered to parents. Close monitoring of the pregnancy is mandatory, mainly based on umbilical artery Doppler velocimetry until term, and continuous cardiotocography during labor is recommended.…”

“…Evidence of true knots of the umbilical cord at birth is not uncommon, with a reported incidence of about 1% of all deliveries,1 and is associated with an estimated risk of antepartum fetal demise that is up to 10 times higher than that in the general population 2. Most true knots present as an unexpected finding at delivery and are not associated with an increased risk of obstetrical intervention and poor neonatal outcome because the larger part of these knots are loose knots 2. On the other hand, the loose knot may tighten during pregnancy because of fetal movements or during labor, leading to fetal distress, asphyxia, and intrauterine death.…”

Personalized Medicine in a Patient With the Antenatal Diagnosis of an Umbilical Cord Knot and a Previous Adverse Outcome for This Reason

“…Sonography has allowed for the in vivo detailed observation of the morphologic characteristics and hemodynamics of the umbilical cord in cases of a true knot of the umbilical cord [1][2][3][4][5][6][7] as well as for insights into the relevance of this antenatal finding. 8,9 Indeed, the fetoplacental circulation can be compromised by a true knot of the umbilical cord, leading to fetal demise.…”