PGF and fetal growth restriction: Not surprisingly, our observed KD falls within the binding affinity reported for both PlGF and VEGF in relationship to the Flt-1 receptor (≈20–200 pmol/L).28,29 Consequently, total PlGF can now be easily calculated from already available free PlGF and sFlt-1 levels, allowing the subsequent evaluation of other groups in whom PlGF might be upregulated or downregulated, for instance in preeclamptic women with intrauterine growth restriction.