Transverse umbilical arterial diameter: technique for the prenatal diagnosis of single umbilical artery.

Abstract

We investigated the relationship between the transverse umbilical arterial diameter and the presence of a single umbilical artery. Further, we speculated that fetal physiologic and hemodynamic limitations in pregnancies complicated by a single umbilical artery would result in larger umbilical arterial diameters than the typical three-vessel cord. The identification of a sufficiently large umbilical artery may be pathognomonic for single umbilical artery. The transverse umbilical arterial diameter was obtained in 100 consecutive, uncomplicated singleton pregnancies between 20 and 38 weeks' gestation. These measurements were compared with the transverse umbilical arterial diameter of 23 pregnancies in which a single umbilical artery was identified with ultrasonography and postnatal examination. Transverse umbilical arterial diameter mea-U sually, the umbilical cord contains two umbilical arteries and one umbilical vein. These vessels are surrounded by Whar-ABBREVIATIONS SUA, Single umbilical artery Received

Sonographic findings of the umbilical cord: implications for the risk of fetal chromosomal anomalies

“…Increased diameter of the umbilical artery or similar diameters of the artery and the vein are also sonographic features characteristic of SUA ( Figure 1). It has been suggested that a transverse diameter of the umbilical artery larger than 4 mm or an umbilical vein to artery ratio ≤ 2 is predictive of SUA 16,17 . However, the limitations and pitfalls of such cutoff measurements in the sonographic diagnosis of SUA were recently pointed out 18 .…”

Antenatal Diagnosis of Aberrant Umbilical Vessels

“…In our case, SUA was clearly observed connect ing to left internal iliac artery. In addition, to discern which is artery or vein precisely, additional examination using color and pulsed Doppler ultrasonography is useful, because SUA is often larger than normal artery, equaling its diameter to that of umbilical vein [ 16], Since Trudinger and Cook [17] first reported the ante natal diagnosis of DUA in 1988, a few cases of DUA have been described antenately. Most anomalies of umbilical vessels have been confirmed after delivery, but the dis tinction of DUA is difficult under the drained and col lapsed umbilical cord after delivery.…”

Prenatal sonographic diagnosis of single umbilical artery

“…As shown in Figures 2 and 3, there was no significant improvement in the detection of SUA using the UV/UA ratio or TUAD, which were reported to be useful in previous studies. 2,3 In evaluations of the UV/UA ratio and TUAD, only 1 case each had values outside the 2-SD limit. These results could be due to interoperator variations or limitations of the ultrasound equipment.…”

“…Sepulveda 2 suggested that an umbilical vein (UV) to UA diameter ratio of less than 2:1 is a good indicator of SUA. In addition, Persutte and Leuke 3 found that a transverse UA diameter (TUAD) measuring more than 4 mm at between 20 and 36 weeks of gestation is useful in the prediction of SUA. Furthermore, the abnormal ratio of systolic to diastolic Doppler flow velocities (S/D ratio) is an index of increased total peripheral resistance, which is usually associated with poor neonatal outcome.…”