Women who suffer a pregnancy complication called preeclampsia seem to pass on the tendency to their daughters, research shows. A new study suggests that women who bear sons after having preeclampsia also convey some risk to their future daughters-in-law.
This seemingly odd conclusion stems from research at the University of Utah School of Medicine in Salt Lake City. There, scientists have found that men who were born of mothers with preeclampsia are twice as likely to father children through preeclamptic pregnancies as are men born of normal pregnancies.
A man can pass genetic flaws on to his offspring at conception. It appears that some still-unidentified genetic traits can contribute to preeclampsia in his mate, says study coauthor M. Sean Esplin, an obstetrician at Utah. The work reinforces the notion that the condition–at least some of the time–is triggered by characteristics of the fetus, not the mother, he says. The study appears in the March 22 New England Journal of Medicine.
“This is a very interesting and potentially useful study that provides evidence that males contribute to preeclampsia,” says James L. Mills, a pediatrician and epidemiologist at the National Institute of Child Health and Human Development in Bethesda, Md. By reviewing the medical records of three generations within families, he says, the researchers avoid the imprecision of personal recall.
Preeclampsia, which usually strikes in the third trimester of a pregnancy, is marked by high blood pressure, swelling, and protein in the urine. It sometimes leads to eclampsia, which can include seizures, coma, and death. For preeclampsia, physicians often prescribe rest and blood pressure medication. In severe cases, they will deliver the baby by cesarean section to end the pregnancy, which halts the preeclampsia.
To find a hereditary link between parents and offspring, the researchers identified 298 men and 237 women in Utah born of mothers who had preeclampsia. The scientists matched these people with a control group of 596 men and 474 women born of normal pregnancies.
Next, they compared offspring of the men and women in each group. Only 1.3 percent of children in the male control group were born of preeclamptic pregnancies, compared with 2.7 percent of children fathered by men born of preeclamptic women, the researchers report. Nearly 5 percent of pregnancies among women born of preeclamptic mothers were themselves plagued by preeclampsia, more than triple the control group’s rate. That finding confirms earlier studies.
Researchers have sought the source of preeclampsia for more than 100 years without success. Some studies have hinted that certain genes could play a role, particularly if both parents carry the same recessive gene, Esplin says.
Other research suggests that several gene variations could combine to predispose a person to preeclampsia, says Carl A. Hubel, a physiologist at Magee- Womens Research Institute at the University of Pittsburgh Medical Center.
Preeclampsia is most common in first pregnancies, with less risk in later pregnancies. However, when a women changes partners, the risk rises again, says Mills. Also, a 1998 study in Norway tracked men whose mates had preeclamptic pregnancies. Even with a new partner, these men had nearly twice the average chance of fathering a child through a preeclamptic pregnancy. These factors are all consistent with a paternal link to preeclampsia, Mills says.
Preeclampsia affects about 1 in 20 pregnancies and appears more common in black women than white. The low incidences in the new study reflect the largely white Utah population.