Father's Genes Can Trigger Preeclampsia

Raised risk for pregnancy complication uncovered in Norwegian study

THURSDAY, Sept. 15, 2005 (HealthDay News) -- A father's genes may contribute to his partner's risk of preeclampsia, the dangerously high blood pressure condition that can occur in pregnancy, a Norwegian-American study has found.

It's been known that women born after a pregnancy affected by preeclampsia are at increased risk of experiencing the condition in their own pregnancies. Now, a study of more than 700,000 births in Norway shows that men born after such a pregnancy have a moderately increased risk of fathering a child where the complication occurs, as well, according to a report in the Sept. 15 online issue of the British Medical Journal.

"Clinicians can look at the risk shown in the paper, and see if it is useful in assessing the risk for a woman who has a family history of preeclampsia," said Dr. Allen Wilcox, a senior investigator at the U.S. National Institute of Environmental Health Sciences, who collaborated on the study.

Preeclampsia occurs in about 5 percent of births, affecting 200,000 U.S. pregnancies every year. Abnormally high blood pressure can cut the blood supply of the placenta, which provides food and oxygen to the fetus, potentially causing low birth weight and other problems. The only available treatment is quick delivery of the baby.

The study found that the daughters of women who had preeclampsia during pregnancy had twice the normal risk of having the condition in their pregnancies, as earlier studies have shown. But it also found a 50 percent risk of the condition in pregnancies fathered by men who were born under the same conditions.

"The father's gene is what is contributing to preeclampsia," explained study author Dr. Rolv Skjaerven, an epidemiologist at the University of Bergen. "He has no way he can influence this pregnancy other than by a genetic mechanism."

The genetic link was especially important for severe cases of preeclampsia, which can be fatal to the fetus. The incidence of severe cases of the condition was tripled in pregnancies involving women who were born after preeclamptic pregnancies and nearly doubled for men, the study found.

"Doctors should be aware that these kinds of hazards can result in such cases," Skjaerven said.

The genetic risk can run throughout a family, the study found. Sisters of affected men or women faced double the normal risk of the condition in their pregnancies, even if the condition was not present when they were born.

But the risk for brothers in such cases was not increased, the study found. This suggests that susceptibility can pass from mother to daughter but not mother to son, the researchers said.

"This kind of thinking is new," Skjaerven said. "There have not been previous studies that had this kind of population data."

More information

Find out more about preeclampsia from the Preeclampsia Foundation.

SOURCES: Rolv Skjaerven, M.D., epidemiologist, University of Bergen, Norway; Allen Wilcox, senior investigator, National Institute of Environmenal Health Sciences, Research Triangle Park, N.C.; Sept. 15, 2005, British Medical Journal online
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