Prenatal diagnosis of the umbilical cord torsion at the placental cord insertion site: A case report and literature review.

A 35-year-old woman (gravida 1, para 0) was admitted to our hospital at 28 weeks' gestation with vaginal bleeding from placenta previa. Severe fetal bradycardia was observed during fetal heart rate monitoring. Ultrasonography showed widely dilated veins on the fetal surface of the placenta and an extraordinarily low umbilical artery peak systolic velocity in the Doppler study. Umbilical cord torsion was suspected. On the subsequent day, we performed a cesarean section due to worsening fetal heart rate patterns. Umbilical artery blood gas analysis indicated severe acidemia (pH 7.063), and umbilical cord torsion was confirmed at the placental cord insertion site. Diagnosing UCT prenatally is challenging; however, it can be suspected by scanning for the widely dilated veins on the fetal placental surface, termed as the "Sunset Sign," an abnormally low umbilical artery peak systolic velocity, and other fetal Doppler abnormalities.

A sustained decrease in the systolic/diastolic ratio may be a sign of severe adverse events in the umbilical cord: a report of eight cases.

A high systolic/diastolic (S/D) ratio of umbilical cord blood is a manifestation of intrauterine hypoxia. However, the clinical significance of a persistently decreased S/D ratio of umbilical cord blood has not been reported. We report eight cases of a persistently decreased S/D ratio of umbilical cord blood, with two cases of umbilical thrombus, five cases of excessive torsion, and one case of a true cord knot. Fetuses with a persistently decreased S/D ratio of umbilical cord blood may be at risk, and it may be an important indication of umbilical cord lesions.

In vitro umbilical cord wrapping and torsion: possible cause of umbilical blood flow occlusion.

OBJECTIVE: Intrapartum fetal heart rate decelerations and bradycardia are often attributed to umbilical cord occlusion without knowing the anatomic basis of that occlusion. We hypothesized that umbilical cord twisting while looped around fetal parts could occlude blood flow. METHODS: Using an in vitro preparation, human umbilical cord veins were perfused at one end with water at approximately 40 cm H2O. The cords were looped around pipes that approximated the diameter of fetal body or limb parts, after which the perfused segment of cord was twisted until water flow stopped. The number of rotations needed to stop perfusion was recorded for each length of twisted cord (4, 6 and 8 cm) and for each pipe diameter. RESULTS: There were 21 completed studies. All cords demonstrated that a decreasing number of twists were needed to stop venous flow as the segment twisted became shorter (from 8 to 4 cm). For each segment length, the number of twists required to stop flow decreased as the pipe diameter narrowed. CONCLUSION: This model demonstrates that a wrapped umbilical cord, particularly with a short segment between the placental insertion and the fetal body part, may be predisposed to cord occlusion in response to fetal rotation.