VEGFA and fetal growth restriction: However, there is now a precedent for this: sildenfil citrate 65 and melatonin 66 are undergoing clinical trials for treatment of fetal growth restriction 67, and a novel vascular endothelial growth factor (VEGF) adenoviral gene therapy, which significantly increases uterine blood flow and fetal growth in guinea pigs and sheep, is being tested in humans 68-71.