Prospective study evaluating the association between sFlt-1/PlGF ratio and adverse outcomes in preterm preeclampsia

To estimate the association between maternal sFlt-1/PlGF ratio and adverse outcomes related to preterm preeclampsia. We performed a prospective study including participants with preeclampsia between 24 and 36 weeks of gestation. The sFlt-1/PlGF ratio was measured in maternal serum at admission and was reported according to pregnancy outcomes (delivery in <7 days after admission, severe preeclampsia before term, and serious complications including stillbirth, eclampsia, HELLP syndrome, and acute renal failure). Receiver operator characteristics curve analyses using Youden index were used to determine optimal sFlt-1/PlGF thresholds. Out of 467 participants (median gestation: 34 weeks; interquartile: 31 - 36), 373 (80%) were delivered in <7 days after admission; 387 (83%) developed severe preeclampsia before term; including 18 (4%) with serious complications. Three sFlt-1/PlGF threshold values were identified: 68, 250 and 500. SFlt-1/PlGF ratios less than 68, between 68 and 249, between 250 and 299, and ≥500 were associated with delivery in <7 days after admission (in 54%, 73%, 88% and 91%, respectively, P <0.001), with severe preeclampsia before term (in 51%, 77%, 86%, and 88%, respectively, P <0.001) and with serious complications (in 0%, 0%, 3%, and 8%, respectively, P <0.001). The higher the ratio, the lower the interval between admission and birth [4 days (interquartile: 0-21), 1 (interquartile: 0-8), 0.5 (interquartile: 0-2) and 0 (interquartile: 0-2), respectively, P <0.01]. Among women with preterm preeclampsia, a sFlt-1/PlGF ratio >250 is associated with short admission to delivery interval, severe preeclampsia and serious complications.