PGF and placental insufficiency: Low first trimester serum PlGF concentrations have been suggested to reflect the placental pathology in pre-eclampsia, i.e. in impaired cytotrophoblastic differentiation and invasion and spiral artery formation [33, 34], seen in early-onset or preterm pre-eclampsia; or pre-eclampsia with placental insufficiency or SGA [4, 6, 8, 35].