Transrectal Doppler sonography of uterine blood flow in ewes during pregnancy.

Research paper by Renato Travassos RT Beltrame, Carolina C Covre, Lucas Buss LB Littig, Amanda de Barros AB Martins, Celia Raquel CR Quirino, Aylton Bartholazzi AB Junior, Ricardo Lopes Dias RL da Costa

Indexed on: 22 Feb '17Published on: 22 Feb '17Published in: Theriogenology


In sheep, there is a lack of information on the behaviour of hemodynamic indices and parameters of blood flow velocity of the uterine artery during pregnancy, making it impossible to determine the real meaning of the values found and their probable relevance in normal physiological or pathological states. The objective of the present study was to evaluate the blood flow velocity parameters and hemodynamic indices of the uterine artery in ewes (18) during pregnancy (33). Based on non-invasive colour Doppler sonography, we evaluated the peak systolic velocity (PS), end diastolic velocity (ED), time-averaged maximum and minimum velocity in a cardiac cycle (TAMAX and TAMEAN), pulsatility index (PI), resistance index (RI), systolic/diastolic ratio (S/D), heart rate (HR), arterial diameter (AD) and the blood flow volume (BFV). Examinations started on day 28 and continued at two-week intervals until parturition. The Doppler parameters and the diameter of the uterine artery underwent significant changes during pregnancy. In the evaluated animals, indices related to resistance of the uterine artery, namely the impedance of blood flow, decreased throughout the initial, middle and late stages of gestation (PI: 1.15, 1.04, 0.97; RI: 0.61, 0.59, 0.57; S/D: 2.68, 2.52, 2.39, respectively) (p < 0.05). In contrast, the contents related to higher uterine irrigation increased during gestation (PS, ED, TAMAX, TAMEAN, HR, AD and BFV) (p < 0.05). No differences were found between the means of the variables in relation to the right and left uterine arteries and between single and multiple pregnancies in the hemodynamic indices. The present study is the first to demonstrate changes in uterine hemodynamics throughout pregnancy in sheep.