OP10.08: Is uterine artery blood flow volume correlated to placental site in normal human pregnancies?

1) to correlate uterine artery (UtA) flow volume, diameter and velocity with placental site in normal uncomplicated human pregnancies; 2) to correlate UtA blood flow to UtA Pulsatility Index (PI) in different placental insertions. Seventy-two singleton uneventful pregnancies, with a normal mean UtA PI, were included in the study. UtA was evidenced by power-Doppler mode and sampled 10–15 mm prior to bifurcation. UtA diameter was measured on a perpendicular view after removing power-Doppler. UtA PI and velocity were measured with a Doppler beam angle < 30°. The average of three consecutive diameters and velocities was considered. UtA flow was estimated by the formula Q = hV · πD2/4; h coefficient (0.5) was obtained by an ad hoc mathematical model. Placental site was registered. Forty-six central and 26 lateral placental sites (8/26 right, 18/26 left) were recorded. Gestational age at examination was 22.4 ± 4.8, 20.9 ± 0.6 and 21.2 ± 4.7 weeks, respectively (p NS). 1) With a central placental UtA flow was equally distributed between the two vessels (right UtA 49.7 ± 11.0%, left UtA 50.3 ± 11.0%). Lateral placental site results are shown in the table below. 2) A significant inverse correlation was observed between ipsilateral UtA flow and PI (p < 0.001), but not in the controlateral vessel and in central placenta vessels. 1) In lateral placental insertions UtA flow was higher in the ispilateral than in the controlateral vessel, even this difference not reach a statistical significance; UtA mean velocity was significantly higher in the ispilateral than in the controlateral UtA, while diameter did not differ. In central placentae UtA flow was equally distributed. 2) Ipsilateral UtA flow significantly inversely correlated with PI increase, while controlateral and central placenta vessel flow did not.