<p>Current Perspectives of Prenatal Sonographic Diagnosis and Clinical Management Challenges of Nuchal Cord(s)</p>

Abstract

Umbilical cord accidents preceding labor are uncommon. In contrast, nuchal cords are a very common finding at delivery, with reported incidences of a single nuchal cord of approximately between 20% and 35% of all singleton deliveries at term. Multiple loops occur less frequently, with reported incidence rates inverse to the number of nuchal cords involved. Rare cases of up to 10 loops of nuchal cord have been reported. While true knots of the umbilical cord have been associated with a 4-10-fold increased risk of stillbirth, nuchal cord(s) are most often noted at delivery of non-hypoxic non-acidotic newborns, without any evidence of subsequent adverse neonatal outcome. Prior to ultrasound, nuchal cords were suspected clinically following subtle (spontaneous or evoked) electronic fetal heart rate changes. Prenatal sonographic diagnosis, initially limited to real-time gray-scale ultrasound, currently entails additional sonographic modalities, including color Doppler, power Doppler, and three-dimensional sonography, which have enabled increasingly more accurate prenatal sonographic diagnoses of nuchal cord(s). In contrast to true knots of the umbilical cord (which are often missed at sonography, reflecting the inability to visualize the entire umbilical cord, and hence are often incidental findings at delivery), nuchal cord(s), reflecting their well-defined and sonographically accessible anatomical location (the fetal neck), lend themselves with relative ease to prenatal sonographic diagnosis, with increasingly high sensitivity and specificity rates. While current literature supports that single (and possibly double) nuchal cords are not associated with increased adverse perinatal outcome, emerging literature suggests that cases of ≥3 loops of nuchal cords or in the presence of a coexisting true knot of the umbilicus may be associated with an increased risk of stillbirth or compromised neonatal status at delivery. This commentary will address current perspectives of prenatal sonographic diagnosis and clinical management challenges associated with nuchal cord(s) in singleton pregnancies.

The prediction and assessment of the intrauterine fetal with umbilical cord around neck well-being by daily fetal movement counting chart (DFMC)

“…In this study, we selected the term pregnant women with UCAN, and found that DFMC can reliably predict the safety of the fetus with UCAN in the uterus before delivery. In comparison of the two groups, AFI was not signi cant, and the results were not consistent with those of previous studies [17,18,19] which were positive correlation between AFI and fetal safety in uterus, and this reason may be related to the inconsistent criteria for inclusion of pregnant women without any clear prenatal risk factors. In this study, we found that the fetal intrauterine safety may be related to the loops of UCAN, DFMC, modi ed Fischer score (NST), S/D and mode of delivery by comparison of the prenatal factors.…”

Current Perspectives of Prenatal Sonography of Umbilical Cord Morphology

“…Other than a single umbilical artery, anomalies of the umbilical cord are uncommon yet may be associated with potential fetal compromise. In addition to nuchal loop(s), true knot(s) of the umbilical cord and complex umbilical cord entanglement not covered in this Commentary yet detailed elsewhere, [12][13][14] umbilical cord complications associated with potential fetal compromise/stillbirth, including: umbilical venous and arterial thrombosis, rare tumors (such as hemangioma, angiomyxoma and teratoma), vasa previa may be detected with prenatal sonography, with alert and attentive scanning, as these anomalies may be missed with relative ease. Given the critical function of the umbilical cord in fetal development until such imaging technologies become widely available, it is incumbent upon sonographers to utilize every opportunity (including during repeat sonographic assessments) to evaluate those portions of the umbilical cord availing themselves in real-time to insonation, and potentially utilize other above-mentioned imaging technologies if/when appropriate.…”

“…For detailed prenatal sonographic assessments and suggested management regarding each of these separate entities, the reader is referred to three recently published Commentaries in the Journal. [12][13][14] An interesting observation is the direct association between the length of umbilical cord and degree (number of nuchal cord loops, true knots and coverall complex umbilical cord entanglement). Also of interest is the possible association of an increased risk of fetal growth restriction associated with excessively long umbilical cords, 19,20 and reported fetal thrombotic vasculopathy, which has been reported to predispose the placenta to marked fetal thrombotic vasculopathy.…”

“…Also, not addressed by the governing bodies are the topics of cord entanglement (nuchal cords, true knots of the umbilical cord, or complex entanglement of the umbilical cord) discussed in detail elsewhere. [12][13][14] Respectfully, we submit that the entire length of the umbilical cord available for sonographic assessment should be scanned in detail for potential umbilical cord morphology abnormalities discussed earlier in this article. In the foreseeable future, sonographic resolution will undoubtedly continue to improve, followed by increased diagnostic accuracy.…”

“…Various manifestations of umbilical cord entanglement, namely nuchal cord(s), true knot(s), and complex entanglement of the umbilical cord, have been presented in detail in earlier separately published commentaries in the Journal, and hence, although involving the umbilical cord per se, various manifestations of umbilical cord entanglement and arterial or venous Doppler assessments will not be addressed in this commentary. [12][13][14]…”