Coexisting true umbilical cord knot and nuchal cord: possible cumulative increased risk of adverse perinatal outcome

<p>Current Perspectives of Prenatal Sonographic Diagnosis and Clinical Management Challenges of True Knot of the Umbilical Cord</p>

“…Subsequently, three-dimensional ultrasound has enabled precise depiction of a true knot of the umbilical cord ( Figures 5, 6, 7). [67][68][69][70][71][72][73][74][75][76] Notwithstanding the Figure 4 Power Doppler image depicting a true knot of the umbilical cord. Note the "smiley face" features (almost complete circle of umbilical cord [face outline] surrounding "eyes" and "mouth/smile"), representing the en-face presenting two umbilical arteries and umbilical vein, respectively.…”

“…Two recent reports have addressed prenatal sonographic diagnosis of coexisting true knot of the umbilical cord and nuchal cord. 75,76 We reported a series of three such cases in the third-trimester, in which the true knot of the umbilical cord was located within the loop of nuchal cord itself (Figure 8). 75 Interestingly, following extensive patient counseling, admission for continuous fetal monitoring and administration of intramuscular antenatal steroids to decrease overall prematurity-associated neonatal morbidities, in each of these three cases (in 36-37 weeks' gestation) fetal heart rate monitoring disclosed prolonged fetal bradycardia which led to Cesarean delivery of uncompromised infants (in which all three cases had coexisting nuchal cords with a true knot of the umbilical cord located precisely as depicted by prenatal ultrasound within the nuchal cord loop) (Figure 8).…”

“…75,76 We reported a series of three such cases in the third-trimester, in which the true knot of the umbilical cord was located within the loop of nuchal cord itself (Figure 8). 75 Interestingly, following extensive patient counseling, admission for continuous fetal monitoring and administration of intramuscular antenatal steroids to decrease overall prematurity-associated neonatal morbidities, in each of these three cases (in 36-37 weeks' gestation) fetal heart rate monitoring disclosed prolonged fetal bradycardia which led to Cesarean delivery of uncompromised infants (in which all three cases had coexisting nuchal cords with a true knot of the umbilical cord located precisely as depicted by prenatal ultrasound within the nuchal cord loop) (Figure 8). 75 While clearly one cannot assume that in these cases stillbirth, or other adverse neonatal outcomes would have occurred without intervention (electronic fetal heart rate monitoring following prenatal sonographic diagnosis), in light of the reported 11% of perinatal morbidity and 4 to 10 fold increase in stillbirth associated with this pathology, although unproven, this possibility should be considered.…”

“…76 Interestingly, while a true umbilical cord knot was found in the previously mentioned large population-based study of Linde et al to have a 4-fold risk of perinatal death, coexisting true knot of the umbilical cord and umbilical cord entanglement were noted to have more than additive effect to the association with perinatal death, clearly supporting our earlier reported clinical suspicion of this cumulative effect. 31,75 Thus, we are presented/confronted with potential sonographic diagnosis of a true knot of the umbilical cord in which one cannot predict a favorable outcome (more likely) or conversely, stillbirth or adverse neonatal outcome (a damaged infant at birth). What therefore is expected of sonographers and clinicians?…”

“…Notwithstanding, evidence of even transient umbilical cord compression should be met with administration of intramuscular antenatal steroids to decrease overall prematurityassociated neonatal morbidities and consideration for admission for continuous fetal heart rate monitoring, and delivery performed if warranted (see our management of cases with co-existing true knot and nuchal cord). 75…”