The importance of repeated measurements of the sFlt-1/PlGF ratio for the prediction of preeclampsia and intrauterine growth restriction.

AIMS

The sFlt-1/PlGF ratio has been evaluated as a diagnostic marker for preeclampsia (PE). The aim of this study was to explore the use of the sFlt-1/PlGF ratio as an aid in prediction for PE.

METHODS

150 patients with a high risk for PE were enrolled in this prospective study. Groups were compared according to the pregnancy outcome: controls (n=114), intrauterine growth restriction (IUGR) (n=14) and PE (n=22) with subclassification early PE<34 weeks (n=6). Measurements of sFlt-1 and PlGF were performed on the automated Elecsys system. Statistical comparison of the sFlt-1/PlGF ratio in different outcome groups and a mixed model analysis using random intercept models were performed.

RESULTS

The sFlt-1/PlGF ratio was significantly higher in pregnancies complicated by PE up to 4 weeks before clinical diagnosis compared to controls (106.7 ± 47.7 vs. 21.0 ± 4.1; P=0.02). Levels of the sFlt-1/PlGF ratio were higher throughout pregnancy in women with IUGR compared to PE/control patients (intercept 1.57 vs. 1.30/0.67; P<0.05). The slope for the sFlt-1/PlGF ratio was significantly higher in PE and IUGR pregnancies compared to controls, indicating that a steep increase of the sFlt-1/PlGF ratio correlates with pathologic pregnancy outcomes.

CONCLUSION

The sFlt-1/PlGF ratio can identify pathologic pregnancy outcomes such as IUGR and PE before clinical diagnosis. Repeated measurements are necessary to assess the dynamics in serum values. The time-dependent slope of the sFlt-1/PlGF ratio is predictive for future pregnancy outcome and risk of developing preeclampsia.