PurposeTo analyze the clinical and laboratory factors that potentially affect the diagnosis-to-delivery time in preeclamptic pregnancies.MethodsIn this cross-sectional study, we followed 24 early onset preeclampsia (E-PE) and 26 late-onset preeclampsia (L-PE) cases. Maternal serum samples were obtained at the time of diagnosis and stored at -80 degrees C until ELISA analysis for soluble fms-like tyrosine kinase-1 (SFlt-1) and placental growth factor (PlGF) levels.ResultsThe median follow-up duration was 68 (1-339) h in the E-PE group and 330 (7-1344) h in the L-PE group. Maternal mean arterial pressure (MAP) at hospitalization was the strongest variable, and the sFlt-1/PlGF ratio added significantly to the Cox regression model. In the E-PE cases, the median sFlt-1/PlGF ratio was significantly higher in the subgroup with a follow-up duration>48h than in the subgroup of cases with a follow-up duration48h (5109 vs. 2080; p=0.038), and none of the seven cases with an sFlt-1/PlGF ratio75th percentile delivered during the first 48h. Neither the 24-h proteinuria nor the gestational age at diagnosis added to the predictive power of the MAP at hospitalization.ConclusionIncorporation of the sFlt-1/PlGF ratio to the routine evaluation of preeclamptic pregnancies may help in the prediction of progression and management planning.