Blood Test Evaluates Risk of Preeclampsia

A blood test can help to assess whether a pregnant woman who suffers from pregnancy-induced hypertension, so-called preeclampsia (PE), is at risk for an imminent delivery.

The concentration and ratio of two certain placenta-derived growth factors allows the identification of women at risk and is a reliable tool to discriminate between different types of pregnancy-related hypertensive disorders.

A team of scientists at the Charité University Medicine (Berlin, Germany) investigated 388 singleton pregnancies with normal pregnancy outcome, 164 with PE, 36 with gestational hypertension, and 42 with chronic hypertension. The measured the concentration of two certain placenta-derived growth factors, the soluble fms-like tyrosine kinase (sFlt-1) and placental growth factor (P1GF) in the participant's serum by commercial immunoassays.

The sFlt-1 and P1GF concentrations of each sample were determined in parallel. For each sample sFlt-1/P1GF ratio was calculated. Single measurements were performed for sFlt-1 and P1GF on the fully automated Roche Diagnostics (Penzberg, Germany) Elecsys system (Elecsys P1GF, human P1GF, and Elecsys sFlt-1). Patients with preeclampsia had a significantly increased sFlt-1/PlGF ratio as compared with controls and with patients with chronic and gestational hypertension in <34 weeks and ≥34 weeks. Time to delivery was significantly reduced in women with preeclampsia in the highest quartile of the sFlt-1/PlGF ratio. In patients with especially high test results, delivery resulted within 48 hours.

Preeclampsia is the most common of the dangerous pregnancy complications. It is characterized by elevated blood pressure, protein in the urine and accumulation of excess fluid beneath the skin. If not treated in time, preeclampsia may progress to eclampsia, characterized by tonic-clonic seizures that can possibly result in maternal and infant death.

The sFlt-1/PlGF ratio is a reliable tool to discriminate between different types of pregnancy-related hypertensive disorders and allows the identification of women at risk for imminent delivery. Stefan Verlohren, MD, lead author of the study said, "With this test we can assess the severity of preeclampsia and give a short-term prognosis of the disease course." Further studies will have to evaluate the test's validity in women who have an elevated risk of developing preeclampsia. The study was published online in July 2011, in the American Journal of Obstetrics & Gynecology.

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