The angiography of uterine arteries in non-pregnant, pregnant, and twin-pregnant sheep

Abstract

The shape, size, and connection of uterine vessels change during pregnancy. The mechanism of luteolysis and vascular anastomosis between fetuses in twin pregnancies differs among species. Angiography is used to evaluate the anatomical structure of vessels. In this study, angiography was performed on the uterine vessels, in open, single and twin bearing ewes. Sheep uteri were collected from the slaughterhouse and the gestational age of fetus was determined using ultrasound. Five gestational periods (30–39, 40–49, 50–59, 60–69 and 70–79 days of pregnancy) were considered. Barium sulfate with a concentration of 30% in warm water was used as the contrast agent. The injection volume and angiocath gauge were proportional to the size of the pregnant uterus. The uterine arteries and their branches were accurately observed on radiographs. Additionally, small branches of arteries and even small vessels of caruncles were clearly defined. Unilateral anastomosis was observed between the uterine artery and ovary. Anastomosis occurred between the middle uterine arteries from day 30 of pregnancy. There was no anastomosis between the twins' fetal sacs at days 40–60 of pregnancy. These results demonstrate that angiography is a useful method for imaging the development of uterine arteries during pregnancy in sheep.