New Risk for Pregnancy Toxemia Found

From the WebMD Archives

Jan. 2, 2002 -- Toxemia of pregnancy, known medically as preeclampsia, has sometimes been called "first pregnancy disease." Maybe not any more. A new study suggests that later pregnancies get just as risky if a woman waits 10 years between babies.

Preeclampsia strikes one in 20 pregnant U.S. women. This sudden rise in blood pressure threatens both the unborn child and even the mother. In severe cases, the only cure is immediate induced delivery or C-section.

Nobody knows what causes it, but it's at least twice as common in first pregnancies as during later pregnancies. A clue comes from the fact that preeclampsia is more likely in later pregnancies if the woman has remarried or changed partners since her last pregnancy.

One explanation is that preeclampsia happens when a woman's immune system reacts to genes of the father found in the fetus. By the time a second child comes along, the theory goes, the woman tends to tolerate these new genes. But a second father would bring new genes and new risk.

What if it wasn't the genes at all? In that case, the "second father" observation might just be caused by a longer time between babies. Rolv Skjaerven, PhD, and colleagues at University of Bergen, Norway, tested this idea. They looked at Norway's detailed birth records for more than 550,000 pregnancies between 1967 and 1998.

The findings -- reported in the Jan. 3 issue of The New England Journal of Medicine -- argue against the "second father" theory. Any pregnancy 10 or more years later than the last one carried the same risk of preeclampsia as a woman having a first pregnancy. Risk of preeclampsia went up 12% with every year between pregnancies. A different father did not increase the risk.

Here are some warning signs that you might have preeclampsia and should see a doctor right away:

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