Proteins found in urine of pregnant women could help diagnose preeclampsia

Researchers at Yale School of Medicine have found that specific substances in the urine of pregnant women could serve as a screening/diagnostic tool for preeclampsia (hypertension and proteinuria during pregnancy). The study is published in March issue of American Journal of Obstetrics and Gynecology.

“Preeclampsia is one of the most common causes of maternal mortality in the United States, but establishing a correct diagnosis can be very difficult, especially in women with hypertension prior to pregnancy,” said lead author Catalin Buhimschi, M.D., assistant professor in the Department of Obstetrics, Gynecology and Reproductive Sciences at Yale School of Medicine.

Buhimschi and his colleagues developed a new algorithm to calculate the ratio for the presence or absence of three specific proteins that are normally secreted by human placenta. They examined samples of urine and blood from 132 women, some of whom had other causes of hypertension. The ratio between two of the proteins correctly identified all the women who had severe preeclampsia.

“It will take several years to develop a new diagnostic test,” said Buhimschi. “Many factors are present in the serum and blood, but only the relationship between them has diagnostic significance.”

The proteins studied were vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and their soluble VEGF receptor (sFlt–1). The ratio of sFlt–1 and PlGF had a high sensitivity (88 percent) and specificity (100 percent) for identifying severe preeclampsia, and was more accurate than proteinuria alone.

Buhimschi said current tests such as liver function, proteinuria and platelet count are neither accurate nor sensitive, and results can be confusing, placing women at risk of giving birth prematurely. The current treatment is delivery of the fetus regardless of gestational age. These results provide scientists with a better understanding of the mechanisms of preeclampsia.

Co–authors are Errol R. Norwitz, M.D., Edmund Funai, M.D., Susan Richman, M.D., Seth Guller, M.D., Charles J. Lockwood, M.D., and Irina A. Buhimschi, M.D.