Production of vascular endothelial growth factor and endothelin in the placenta and umbilical cord during normal and complicated pregnancy.

The concentrations of vascular endothelial growth factor and endothelin in the placenta progressively increased during normal pregnancy. Production of vascular endothelial growth factor and endothelin in the placenta exceeded the normal during trimester I miscarriage and trimester III premature birth accompanied by intrauterine hypoxia. The concentration of these vasoactive substances during premature birth also increased in the umbilical cord. The compensatory decrease in the concentrations of vascular endothelial growth factor and endothelin in the placenta and umbilical cord was observed during full-term pregnancy with threatened abortion.