Impacts of maternal nutritional plane on umbilical artery hemodynamics, fetal and placentome growth in sheep

The present study aimed to examine the impact of maternal nutritional plane on umbilical hemodynamics. Ewes (n = 15) were assigned to 1 of 3 dietary treatments [control (CON; 100% of NRC requirements), restricted (RES; 60% of CON) or overfed (OVR; 140% of CON)] beginning on day 40 of gestation. Umbilical artery hemodynamics, fetal growth and placentome growth were measured on days 40, 45, 52, 80, 94 and 108 of gestation by Doppler ultrasonography. The percentage change in umbilical artery pulsatility and resistance indices remained steady through day 80 of gestation, and then decreased (P < 0.03) by day 108 of gestation. Moreover, plane of nutrition affected (P < 0.03) the percentage change in pulsatility index from day 40, with RES ewes having a greater (P < 0.03) change compared to CON (16.7 +/- 7.5 vs. -15.6 +/- 7.5%), with OVR being intermediate (3.2 +/- 7.5%). Fetal biparietal and abdominal diameters increased (P < 0.01) throughout gestation, and fetal heart rate decreased (P < 0.01) from day 52 to 108 of gestation. Placentome diameter increased (P < 0.01) through day 80 of gestation, was similar (P > 0.05) on days 80 and 94 of gestation, and then decreased (P < 0.01) by day 108 of gestation. Maternal plane of nutrition can impact umbilical resistance indices, and ultimately may impact blood flow to the fetus.