PGF and preeclampsia: The PROGNOSIS study (Prediction of Short-Term Outcome in Pregnant Women with Suspected Pre-Eclampsia Study), which was a major prospective clinical trial, established cut-off values of the sFlt-1/PlGF ratio for the screening of preeclampsia: a sFlt-1/PlGF ratio ≤ 38 ruled out the onset of pre-eclampsia within one week, regardless of the gestational age.