Single Umbilical Artery—right or Left? Does It Matter?

Abstract

Ultrasonographic prenatal diagnosis of single umbilical artery (UA) is well documented, but the exact siding of the single UA and its correlation with the occurrence of other congenital malformations and the outcome of the baby remain unclear. We report our experience with 46 cases of prenatally diagnosed single UA. This is the first prospective study of a large number of consecutive pregnancies in which the side of the existing artery was identified in fetuses with a single UA. Most of the cases were identified by transvaginal sonography at 14–16 weeks' gestation. A right artery was detected in 25 fetuses (54·3 per cent), and a left artery in 21 cases (45·7 per cent). Six fetuses (13 per cent) had associated anomalies, five of them in the urinary system. No correlation was found between the type or severity of the malformations and the side of the missing (or existing) UA. In our experience, the exact location of the single UA can be reliably determined by ultrasonography from the beginning of the second trimester of pregnancy. The selection process of the missing (or existing) vessel is likely to be random, even though a right single artery was seen slightly more often. © 1997 by John Wiley & Sons, Ltd.

Isolated single umbilical artery and fetal karyotype

“…The findings of this study confirm the results of previous reports of a high association between an SUA and chromosomal abnormalities, most commonly trisomy 182–19. However, in all chromosomally abnormal fetuses there were one or more fetal defects.…”

“…A single umbilical artery (SUA) is found in about 1 in 200 deliveries1. Ultrasonographic studies in the second and third trimesters of pregnancy have reported chromosomal abnormalities in about 10% of fetuses with SUA, most commonly trisomy 18 (Table 1)2–19. It has therefore been recommended that such pregnancies should be offered fetal karyotyping.…”

Perinatal results following the prenatal ultrasound diagnosis of single umbilical artery

“…It is greater among the population with a high risk of malformation and in the prenatal studies carried out. So it varies between 3.1 per 1000 in the Gornall series (5), obtained postnatally in a general population, and 1.2–2% (6) in prenatal series. It is three or four times more frequent in twin pregnancies.…”

“…This is not always detected by ultrasound; thus, the anomalies not diagnosed may be 7% (16). Table III summarizes the studies published and the variation of the findings of malformations and chromosomal alterations between one author and another (5, 6, 14, 17). As can be seen, our data are very similar to the Gornall series, which was carried out postnatally, studying NB with SUA diagnosed immediately after birth when checked by the pediatrician.…”

Letter to the editor. Re: ‘Single umbilical artery—right or left? Does it matter?’ by Blazeret al.

“…We read with interest the article of Blazer et al (1997) on the subject of single umbilical artery in the fetus. The authors report their experience with 46 cases of prenatally diagnosed single umbilical artery and state that 'this is the first prospective study of a large number of consecutive pregnancies in which the side of the existing artery was identified'.…”