Umbilical artery

Artery: Umbilical artery
Fetal circulation; the umbilical vein is the large, red vessel at the far left. The umbilical arteries are purple and wrap around the umbilical vein.
Scheme of placental circulation.
Latin	a. umbilicalis
Gray's	subject #139 540
Source	internal iliac artery
Branches	superior vesical artery artery of the ductus deferens
Drain	umbilical vein
MeSH	Umbilical+Arteries

The umbilical artery is a paired artery (with one for each half of the body) that is found in the abdominal and pelvic regions. In the fetus, it extends into the umbilical cord.

Umbilical arteries in the fetus

Umbilical arteries supply deoxygenated blood from the fetus to the placenta in the umbilical cord. There are usually two umbilical arteries present together with one umbilical vein in the cord. The umbilical arteries are actually the latter of the internal iliac arteries that supply the hind limbs with blood and nutrients in the fetus. The umbilical arteries surround the urinary bladder and then carry all the deoxygenated blood out of the fetus through the umbilical cord.

The umbilical arteries are the only arteries in the human body, aside from the pulmonary arteries, that carry deoxygenated blood.

Single Umbilical Artery

Occasionally, there is only the one single umbilical artery (SUA) present in the cord. Approximately 1 in 100 newborns are found to have a SUA, making it the most common umbilical abnormality. It is more common in multiple births. Babies with SUA may have a higher likelihood of having other congenital abnormalities. However, additional testing (high level ultrasound scans) can rule out many of these abnormalities prior to birth and alleviate parental anxiety. Echocardiograms of the fetus may be advised to ensure the heart is functioning properly. Genetic counseling may be useful, too, especially when weighing the pros and cons of more invasive procedures such as chorionic villus sampling and amniocentesis.

Although the presence of an SUA is a risk factor for additional complications, most fetuses with the condition will not experience other problems, either in utero or after birth. Especially encouraging are cases in which no other soft markers for congenital abnormalities are visible via ultrasound. Prior to ultrasound technology, the only method for determining the presence of a SUA was at birth, following an examination of the placenta. Given that the vast majority of expectant mothers do not receive the kind of advanced ultrasound scanning required to confirm SUA in utero, most cases may never be detected antenatally even today.

Doctors and midwives often suggest parents take the added precaution of having regular growth scans near term to rule out intrauterine growth restriction, which can happen on occasion and warrant intervention. Yet the majority of growth restricted infants with the abnormality also have other defects. Finally, neonates with the finding may also have a higher occurrence of kidney problems, so close examination of the infant may be warranted shortly after birth. Among SUA infants, there is a slightly elevated risk for post-natal urinary infections.

Umbilical artery in the adult

The umbilical artery is a branch of the anterior division of the internal iliac artery and represents the patent (open) part of the embryonic umbilical artery. (The non-patent obliterated part of the artery is the medial umbilical ligament.) The umbilical artery is found in the pelvis, and gives rise to the superior vesical arteries. In males, it also gives rise to the artery to the ductus deferens.

Additional images

Model of human embryo 1.3 mm. long.

Transverse section of human embryo eight and a half to nine weeks old.

Tail end of human embryo twenty-five to twenty-nine days old.

Inguinal fossae

External links

• 1349189694 at GPnotebook
• SUNY Labs 43:13-0203 - "The Female Pelvis: Branches of Internal Iliac Artery"

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