Prediction of Imminent Preeclampsia at 35–37 Weeks Gestation

13 Mar, 2019 ,
American Journal of Obstetrics and Gynecology
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American Journal of Obstetrics and Gynecology
13 Mar, 2019 ,

Anca Ciobanu, MD et al studied 15,247 pregnancies from 2 maternity hospitals in England in this prospective observational study, to compare the performance of screening for delivery with preeclampsia at ≤2 and ≤4 weeks after assessment at 35+0–36+6 weeks gestation between the use of percentile cut-offs in placental growth factor alone or the soluble fms-like tyrosine kinase-1/placental growth factor ratio and the competing risks model. They identified 326 pregnancies (2.1%) that subsequently experienced preeclampsia. Outcomes revealed the superior performance of screening for imminent delivery with preeclampsia by the competing risks model when compared to that of placental growth factor alone or the soluble fms-like tyrosine kinase-1/placental growth factor ratio at 35+0–36+6 weeks gestation.

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Prediction of imminent preeclampsia at 35–37 weeks gestation

Anca Ciobanu, MD et al, American Journal of Obstetrics and Gynecology (13 March 2019)

Abstract

Background

In the weeks preceding the clinical onset of preeclampsia, the maternal serum level of the angiogenic placental growth factor is decreased and that of the antiangiogenic factor soluble fms-like tyrosine kinase-1 is increased. Women presenting at specialist clinics with signs or symptoms of hypertensive disorders have been stratified according to concentrations of placental growth factor or the ratio of concentrations of soluble fms-like tyrosine kinase-1 and placental growth factor to determine clinical management for the subsequent 1-4 weeks. An alternative approach for the prediction of preeclampsia is use of the competing risks model, a Bayes’ theorem based method, to derive patient-specific risk for preeclampsia by various combinations of maternal characteristics and medical history with multiples of the median values of biomarkers.

Objective

The purpose of this study was to compare the performance of screening for delivery with preeclampsia at ≤2 and ≤4 weeks after assessment at 35+0–36+6 weeks gestation between the use of percentile cut-offs in placental growth factor alone or the soluble fms-like tyrosine kinase-1/placental growth factor ratio and the competing risks model.

Study Design

This was a prospective observational study in women who attended a routine hospital visit at 35+0–36+6 weeks gestation in 2 maternity hospitals in England. The visits included the recording of maternal demographic characteristics and medical history and the measurement of serum placental growth factor and soluble fms-like tyrosine kinase-1 and mean arterial pressure. The areas under the receiver operating characteristics curves were used to compare the predictive performance for preeclampsia with delivery at ≤2 and ≤4 weeks from assessment of screening by placental growth factor alone and the soluble fms-like tyrosine kinase-1/placental growth factor ratio with that of a previously developed competing risks model with a combination of maternal factors, placental growth factor, soluble fms-like tyrosine kinase-1, and mean arterial pressure (triple test).

Results

First, the study population of 15,247 pregnancies included 326 pregnancies (2.1%) that subsequently experienced preeclampsia. Second, in the screening for delivery with preeclampsia at ≤2 and ≤4 weeks from assessment, the performance of the triple test was superior to that of placental growth factor alone or the soluble fms-like tyrosine kinase-1/placental growth factor ratio. The area under the receiver operating characteristics curves for preeclampsia at ≤2 weeks in screening by the triple test (0.975; 95% confidence interval, 0.964–0.985) was higher than that of placental growth factor alone (0.900; 95% confidence interval, 0.866–0.935; P<.0001) and the soluble fms-like tyrosine kinase-1/placental growth factor ratio (0.932; 95% confidence interval, 0.904–0.960; P=.0001). Similarly, the areas under the receiver operating characteristics curves for preeclampsia at ≤4 weeks in screening by the triple test (0.907; 95% confidence interval, 0.886–0.928) was higher than that of placental growth factor alone (0.827; 95% confidence interval, 0.800–0.854; P<.0001) or the soluble fms-like tyrosine kinase-1/placental growth factor ratio (0.857; 95% confidence interval, 0.830–0.883; P<.0001). Third, at most, screen-positive rates of 2–30% the detection rate of delivery with preeclampsia at ≤2 and ≤4 weeks that was achieved by the triple test was approximately 10% higher than that of the soluble fms-like tyrosine kinase-1/placental growth factor ratio and 20% higher than that of placental growth factor alone; the negative predictive value was similar for the 3 tests.

Conclusion

At 35+0–36+6 weeks gestation, the performance of screening for imminent delivery with preeclampsia by the competing risks model is superior to that of placental growth factor alone or the soluble fms-like tyrosine kinase-1/placental growth factor ratio.