Abstract
The aim of present study was to examine the changes in blood flow indices throughout pregnancy in singleton and multiple pregnant does. Doppler scanning was done to assess resistance index (RI), pulsatility index (PI), time-averaged maximum velocity (TAMV) and blood flow volume (Vol). The placentomes were investigated for blood indices on day 45 as an echogenic structure on the surface of the endometrium. Transrectal ultrasonography was performed every 30 days during the overage of the pregnancy. Diameters of largest six placentomes from each doe were measured using an ultrasonography device, and the mean values of placentome diameters were calculated. Values of RI and PI exhibited a steady decrease toward term and declined more rapidly and earlier in multiple than in single pregnancies. Values of RI and PI were negatively correlated with placetome size; however, values of TAMV and Vol were positively correlated with placentome size. In singleton and multiple pregnancies, the placentome size showed an increase toward term, but there is no difference in placentome size between single and multiple bearing does. In conclusion, the values of TAMV and Vol for multiple pregnancies were significantly higher than for singleton at any gestational month to satisfy the high foetal demand of nutrients and dissolved oxygen for foetal progression. Knowing the relationship between the foetal number and blood flow parameters could be used in the clinical management of such pregnancies and the early detection or prediction adverse pregnancy outcome.