FLT1 and preeclampsia: The PRediction of short-term Outcome in preGNant wOmen with Suspected preeclampsIa Study (PROGNOSIS) demonstrated that a soluble fms-like tyrosine kinase 1/placental growth factor (sFlt-1/PlGF) ratio ≤ 38 ruled out the occurrence of preeclampsia in the next week with a negative predictive value of 99.3%; a ratio > 38 indicates an increased risk of developing preeclampsia in the next 4 weeks.