A new test that checks the level of a placental protein could help doctors determine if a woman will develop a severe form of high blood pressure during pregnancy, according to a study in the American Heart Association journal Circulation.

High blood pressure affects 6 percent to 8 percent of pregnant women in the United States, according to the National Heart, Lung, and Blood Institute.

Preeclampsia is a complex form of high blood pressure in pregnancy that can damage the kidneys, liver and brain and lead to fetal complications such as premature delivery, low birth weight and stillbirth.

"The test is designed to differentiate women with preeclampsia from those with high blood pressure alone," said Lucy Chappell, Ph.D., clinical senior lecturer in Obstetrics at King's College in London. "Current tests for the condition only detect that it's happening, rather than predicting it, and by that time the disease has progressed and has likely already caused organ damage.

"The test identifies women at high risk for developing preeclampsia, so doctors can better monitor and treat the blood pressure. It also prevents unnecessary hospitalizations of those who are not likely to develop preeclampsia."

The study included 625 patients from various centers in the United Kingdom, of which 61 percent developed preeclampsia.

Women in the study with low levels of the protein placental growth factor (PlGF) developed preeclampsia. If protein levels were less than 100 pg/mL at less than 35 weeks of pregnancy, the baby was likely delivered within 14 days, researchers said. In a normal pregnancy, the level of placental growth factor is 100-3,000 pg/mL and doesn't decrease.

"I would propose that further assessment of PlGF should be undertaken to measure the impact of changing diagnostic and treatment decisions on the health of mother and baby," Chappell said.