Oral or Poster Presentation
Plenary Session - Innovation & Outreach
Introduction: Preeclampsia (PE) and fetal growth restriction (FGR) are often characterized by high placental vascular resistance that hinders uterine artery (UtA) blood flow and fetal substrate delivery. Resveratrol (RSV), a polyphenol, increases UtA blood flow, fetal oxygenation and fetal weight (Darby et al., J Physiol, 2018). However, the effects of sustained increased UtA blood flow on placental and fetal circulatory physiology in normotensive and healthy pregnancies have yet to be fully quantified.
Methods: Merino twin bearing ewes were subcutaneously implanted with a slow-release RSV (n=6 or vehicle (VEH, n=5) capsule at 113 days(d) gestational age (GA; term=150d). Fetal femoral vessels were catheterised at 119d GA. Phase-contrast, T2 oximetry and 3D volumetry MRI techniques were performed at 124d to quantify blood flow and oxygen saturation (SO2) of major fetal and placental vessels, as well as fetal body volume and weight. Significant differences (P<0.05) were assessed using an unpaired t-test.
Results: Maternal RSV increased total fetal twin weight compared to VEH measured on the day of MRI (Fetus A + Fetus B; 6.14 vs 5.26 kg; P<0.05). There were no differences in fetal blood flow or SO2 in major vessels and thus no difference in oxygen delivery and consumption in the fetus and fetal brain between RSV and VEH. However, differences in UtA blood flow (P<0.05) were closely related to changes observed in placental oxygen delivery when normalized to maternal weight (P=0.06), with no change in placental weight.
Conclusion: Maternal RSV significantly increased UtA blood flow and fetal size, but there was no significant change in placental or fetal oxygen consumption. The use of vasodilatory compounds such as RSV may improve outcomes in PE and FGR with no observed negative effects on fetal hemodynamics. However, further investigation of the mechanism(s) accounting for the changes in fetal growth associated with RSV administration is warranted.