Alongside placental growth, soluble fms-like tyrosine kinase-1 (sFlt-1) rises too; an adaptive response to rising PlGF towards and during mid-gestation is an increasing level of sFlt-1 compared to weakly increasing PlGF, which indicates an anti-angiogenic state and is often pre-clinical evidence of other placental biomarkers relating to other pregnancy complications like preeclampsia and also have been shown to demonstrate placental insufficiency. This evidence concerns the gene PGF and placental insufficiency.