Scientists say they have identified early indicators of whether a woman will develop a potentially life-threatening condition during her pregnancy. Further studies are under way to determine if the findings hold up as a predictor of the condition, which could then be managed before it becomes a problem.
Preeclampsia is a leading cause of mother and infant mortality worldwide, affecting an estimated three to five percent of pregnant women.
In its early stages, the disease is marked by an increase in blood pressure and protein in the urine. If not treated promptly, preeclampsia leads to the more serious condition, eclampsia, in which a pregnant woman can go into convulsions and sometimes die. Children who survive may suffer permanent complications, such as blindness, cerebral palsy and learning difficulties.
Until now, no one has been sure what causes the condition. But in a paper published in The New England Journal of Medicine, researchers report zeroing in on two proteins that appear to weaken the mother's blood vessels to her fetus.
Study co-author Richard Levine of the U.S. National Institute of Child and Human Development says one of the proteins, called s-Flt1, is elevated in women who go on to develop preeclampsia.
"The molecule is like glue, and it removes from the circulation molecules that are needed to maintain the health of blood vessels. So, these blood vessels become unhealthy and that leads to the signs of preeclampsia."
Researchers say elevated levels of a second protein - called endoglin - appear to harm blood vessels, as well.
The researchers concluded that elevated levels of both proteins indicate risk of preeclampsia. The findings could allow doctors to predict whether women are at risk for preeclampsia two to three months before onset of the disease.
Eleni Tsigas, the president of the Preeclampsia Foundation here in the United States, says "[From] the perspective of patients, who have endured preeclampsia, prediction can truly mean the difference between a crisis pregnancy and a managed problem. It can literally mean the difference between life and death of the baby, or even the mother."
Death in childbirth caused by the disease is rare in Western countries because of good medical care. In developing countries, where medical care may be poor, serious complications are much more common.
The World Health Organization is conducting a study to see whether it is possible to predict high-risk pregnancies.
Jose Villar, former head of maternal and fetal medicine at WHO, will be overseeing the three-year study in Kenya, Thailand and India.
Villar says investigators will test some 10,000 women for the two proteins.
"We did a systematic review of the literature, and carefully evaluated all of the studies published, and we found that [these are] very promising markers," said Villar.
Villar adds that women at risk for preeclampsia will be referred to regional medical centers for care.