Hemodynamic changes in arterial flow velocities throughout the first six months of pregnancy in buffalo heifers by Doppler ultrasonography

Abstract

Objective: To assess blood flow parameters as well as Doppler indices at the first six months of pregnancy in buffalo heifers. Methods: A total of 15 healthy, cycling, buffalo heifers were examined twice per month. Examination of Doppler ultrasonography started from the first month till the sixth months of pregnancy. All animals were subjected to transrectal Doppler ultrasonography to assess ovarian and uterine blood flow. Resistance index, pulsatility index, peak systolic velocity, end diastolic velocity, and blood flow rate were measured of both ipsilateral and contralateral to the fetus side. Results: The resistance index was positively correlated with the pulsatility index (r=0.62, P<0.01) but negatively correlated with all other parameters. For both ovarian and uterine arteries ipsilateral and contralateral to the fetus, there was a reduction in the resistance index, with a significant increase (P<0.01) in peak systolic and end diastolic velocities in both ovarian and uterine arteries. The peak systolic and end diastolic velocities of the ipsilateral ovarian and uterine arteries increased linearly till the six months of pregnancy with increased growth demands of the fetus. The same for the uterine branch of the ovarian artery was done in the middle uterine artery and umbilical artery ipsilateral to the fetus side. Conclusions: This study provides reference data of the hemodynamic changes in both ovarian and uterine arteries that could be a valuable tool to evaluate all hemodynamic changes in the developing placenta/fetus. Transrectal Doppler ultrasonography proves to be a useful non-invasive method to assess utero-ovarian blood flow during pregnancy.