Primate maternal placental angiography

Background: In humans, it is known that blood flow is directed to the gravid uterus from two (right and left) pelvic uterine arteries. The extent of supply from the tubo-ovarian anastomosis (joining of the ovarian and uterine arteries) is unknown. The aim of this study was to delineate the arterial blood supply to the placenta via systematic angiography in normal pregnancies in a non-human primate, the baboon (Papio hamadryas). Methods: The assessment of the distribution of blood supply with single-shot 3-vessel angiography (aorta, right and left common iliac arteries), allowed assessment of bilateral supply and possible ovarian supply (n = 9). In 2-vessel pictures (aorta and left or right iliac), the contralateral supply was determined by subtraction of the ipsilateral supply from the total supply (n = 7). The studies were all approved by the Institutional animal welfare committee and were conducted as part of a broader project investigating preeclampsia. Results: The animals were 9 years of age and 140 days of gestation for the 3 vessel study and 154 days of gestation for the 2 vessel study. The angiograms were more likely to have cotyledons perfused by the left uterine artery (p = 0.012) than the right. Overall, 55% of placentae had 5–44% of supply overlapping and 22% had 10–15% ovarian contribution to blood supply. Discussion: This study demonstrates the variation in primate uteroplacental blood flow including the contribution of ovarian arteries and left and right collateralization. Similarity to human vascular anatomy strengthens the use of primate species as a model of human placentation.