High Cholesterol Linked to Toxemia in Pregnancy
Oct. 1, 1999 (Washington) -- Women who have an elevated cholesterol level before getting pregnant are twice as likely to develop a serious condition called preeclampsia during pregnancy, compared with women with normal cholesterol levels. That's according to research published in the October issue of the journal Obstetrics and Gynecology.
Lead author Ravi Thadhani, MD, MPH, tells WebMD, "This certainly would support checking cholesterol levels earlier in a woman's life, but we do not know the specific levels or what types of cholesterol" may trigger preeclampsia. "That needs to be worked out before any specific recommendations are made," he says.
Preeclampsia, also known as toxemia of pregnancy, is the development of high blood pressure, kidney problems, and/or severe swelling during pregnancy. The condition occurs in 5-10% of all pregnancies but is most common during the last trimester of a first pregnancy. If the disorder continues to progress, it can lead to eclampsia, which is characterized by seizures in the mother and sometimes death, if left untreated.
"Known risk factors for preeclampsia -- a twin pregnancy, preexisting [high blood pressure], obesity, diabetes -- only account for 14 to 15 percent of all cases," says Thadhani. "This might improve our ability to predict who gets this disorder," he says. Thadhani is a nephrologist with Massachusetts General Hospital and an instructor at Harvard Medical School.
Delivery is the only certain way of ending the condition. "Preeclampsia can be quite severe, and it can become quite severe in a matter of hours," Thadhani says. "Most often women are admitted to the hospital [with toxemia] and have to deliver immediately."
Thadhani and colleagues looked at more than 15,000 women who were part of the national Nurses Health Study II, which is based at the Harvard School of Public Health. When the study began in 1989, the women were aged 25 to 42 years had delivered at least one baby, and had no reported history of high blood pressure.
They completed questionnaires every two years with self-reported information about body weight and history of elevated cholesterol levels, verified with medical records. The researchers confirmed 86 cases of preeclampsia.
"A history of elevated cholesterol was not associated with the risk of developing gestational hypertension. However, women with a history of elevated cholesterol were at increased risk of developing preeclampsia," the authors write. Gestational hypertension is high blood pressure that develops during a pregnancy.
Thadhani and his colleagues did find that women who were approximately 30% overweight were at increased risk of preeclampsia, a finding that has been shown by other researchers.
"A woman who is thin and has high [cholesterol] has a higher risk of preeclampsia, as does a woman who is obese," Thadhani says. "This may be a potentially modifiable risk factor. What we tried to do was look at [cholesterol levels] independent of their association with hypertension and [obesity], which are also associated with elevated [cholesterol] and are known risk factors for preeclampsia that are difficult to modify."
Thadhani is continuing to research the link between preeclampsia and high cholesterol. He plans to study 8,000 women who seek prenatal care at Massachusetts General Hospital over the next five years.