Evaluation of changes in Doppler ultrasonography indices and levels of maternal serum angiogenic factors throughout pregnancy in ewes.

We evaluated the changes in the pulsatility index (PI) and resistance index (RI) of fetal and maternal vessels and maternal serum angiogenic factors throughout pregnancy in 20 Kivircik ewes. They were examined for pregnancy detection on Day 30 after mating. The PI and RI during the pregnancies were followed using Doppler ultrasonography (USG) of the uterine artery, umbilical artery, fetal aorta, and fetal vena cava. Doppler USG was performed every 15 days beginning from the 40th day after mating. Blood samples were collected every 15 days starting from the day of mating. Nitric oxide (NO), vascular endothelial growth factor, basic fibroblast growth factor, and angiopoietin-1 and -2 levels were measured in maternal serum. A gradual decline was observed in the PI and RI of the umbilical artery beginning from Day 75 of pregnancy. Similarly, the RI of the uterine artery decreased on Day 135. Embryonic resorption was detected in two ewes with an increased PI and RI in the uterine artery. A significant and gradual decrease in the maternal serum vascular endothelial growth factor level was observed throughout pregnancy. The maternal serum NO level increased beginning from Day 135 of pregnancy. The results of this study illustrate the progressive changes in the Doppler USG findings of fetomaternal vessels and maternal serum angiogenic factors that occur throughout ewe pregnancy. The umbilical and uterine artery Doppler USG findings and maternal serum NO concentration may be important parameters for evaluation of the course of pregnancy in ewes. The results of this study should be compared with those of further studies that include compromised pregnancies and nonpregnant ewes.

Is uterine blood flow influenced by hCG and mare age?

Doppler ultrasonography is a noninvasive technique which enables us to follow the physiologic and physiopathologic changes in blood flow in tissues. It is becoming an essential tool in veterinary medicine, especially in theriogenology. Twenty-seven Arabian mares were grouped by age ('young', 3-10 y, n=15; 'old', 19-23 y, n=12). The uterine arteries of the mares were examined using Doppler ultrasonography when an ovarian follicle ≥35mm was visible (Day -1). After these measurements, human chorionic gonadotropin (hCG; 2500IU) was administered to 14 mares selected randomly. One day later (Day 0) Doppler ultrasonography was repeated and then the dominant follicles were aspirated to collect follicular fluid in all groups. On the next day (Day +1), Doppler indices of the uterine artery blood flow were measured again. Blood samples were also collected just prior to ultrasonography, for measuring serum estradiol and progesterone levels. We found that preovulatory hCG administration had no significant effects on uterine artery blood flow indices, or serum or follicular fluid estradiol concentrations. The uterine artery resistance index might decrease in young mares after ovulation, possibly because of increased uterine perfusion.