The causes of preeclampsia, a multi-system disorder that affects women in pregnancy, have not been fully elucidated. The condition, which is typically associated with high blood pressure and an increased amount of protein in the urine, affects 2 to 5 percent of pregnant women, and is one of the main reasons for complications during the second half of pregnancy. Preeclampsia is frequently diagnosed too late and, in the most severe cases, can be fatal for both mother and child.
So far, hypertension and an increased amount of protein in the urine have proven unreliable in predicting the onset of the condition and its complications. As part of the PROGNOSIS study, researchers were able to determine a cutoff value for the ratio of serum sFlt-1 to PlGF, which allows them to reliably rule out the condition within one week, and to predict the development of the condition and its complications. The ratio of sFlt-1 to PlGF, two proteins produced by the placenta and released into the maternal circulation, plays an important role in the development of the condition. A blood test, which can be used even in the absence of any symptoms, and which determines the ratio of these two placental proteins, can now be used to predict whether a pregnant woman will develop preeclampsia or the typical complications associated with it. More than 1,000 women with a high risk of preeclampsia, or presenting with clinical symptoms of the condition, were evaluated as part of this multicenter study.
"The main problem with preeclampsia is that clinical presentation is variable and symptoms are often too nonspecific to allow a clear diagnosis. The ratio of serum sFlt-1 to PlGF can help us to better predict the risk of disease onset or its progression," emphasizes Dr. Stefan Verlohren, the study's corresponding author. Dr. Verlohren, who hails from Charité's Department of Obstetrics, goes on to add that: "this allows us to avoid preterm deliveries and delays in starting treatment. The main thing, however, is the fact that it is now possible to reliably rule out disease onset for one week; this will considerably reduce anxiety for the mother."
A total of 1,273 pregnant women with suspected preeclampsia, and recruited from 14 different countries, took part in the study. All participants underwent blood tests to determine the ratio of serum sFlt-1 to PlGF. A sFlt-1 to PlGF ratio of 38 or lower was shown to have a negative predictive value of close to 100% for ruling out preeclampsia within one week. A value of more than 38 had a positive predictive value of 36.7% for predicting preeclampsia over the next four weeks, and a predictive value of 65.5% for predicting maternal or fetal complications over the next four weeks.
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