FRIDAY, March 28 (HealthDay News) -- Giving birth early seems to increase a woman's risk of having high cholesterol later, a new study shows.

And that raises the chances of heart disease even further down the line for these women, the researchers added.

The findings were presented Thursday at the Society for Gynecologic Investigation annual meeting, in San Diego.

"Total cholesterol and LDL cholesterol were elevated in women who'd had a preterm birth, before 34 weeks," said study author Janet Catov, an assistant professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine.

Catov said it's hard to know yet whether there's something in the pregnancy or preterm delivery that triggers the high cholesterol, or if it's the high cholesterol that may have something to do with the preterm delivery. She did note that "very early in pregnancy, women with preterm birth have elevated lipids, which may be exacerbated in pregnancy."

Another recent study found that women with very low levels of cholesterol were also at risk of preterm birth, but Catov said this study showed that women on the very high end of cholesterol levels also went on to give birth prematurely.

"Perhaps there's a normal range, and if you're higher or lower, it could be a problem," she said.

In the current study, Catov and her colleagues compared 47 women who'd had a preterm birth, defined as giving birth before 37 weeks of gestation, to 104 women who gave birth to full-term infants. Most of the women in the preterm group gave birth before 34 weeks of gestation.

Women who had other chronic medical conditions, such as preeclampsia or a baby with signs of growth restriction, were excluded from the study.

Blood samples were taken an average of 7.4 years after delivery.

Women who'd given birth before 34 weeks of gestation had the highest levels of total cholesterol at 202.6 mg/dl. Women who gave birth between 34 and 37 weeks had levels of 190.1 mg/dl, and women who carried their babies to term had levels of 180.1 mg/dl.

After adjusting for race, smoking history and body mass index, the researchers found that women who gave birth prematurely had a 2.3 times greater risk of developing cholesterol levels above 240 mg/dl, a level considered high risk by the American Heart Association.

Additionally, women who'd had a preterm birth were 3.3 times more likely to have elevated LDL -- the "bad" cholesterol -- than women who gave birth to full-term babies.

"What this study tells us is that a woman's previous medical history, particularly conditions that happen during pregnancy, may be a clue to her later heart disease risk," said Dr. Nieca Goldberg, director of the New York University Medical Center's Women's Heart Program.

"I would advise a woman who's had a preterm birth and who now has high cholesterol to have her cardiac risk factors evaluated at regular intervals, at least with a yearly physical," said Goldberg.

While Catov said these findings need to be duplicated in a larger study before any specific guidelines or recommendations can be made, she said it's a good idea to "keep your doctor apprised of your medical conditions and preterm births or other adverse pregnancy outcomes, and keep up to date with recommended screenings."

More information

To learn more about cholesterol and how to lower your levels, visit the American Heart Association.

SOURCES: Janet Catov, Ph.D., assistant professor, obstetrics and gynecology, University of Pittsburgh School of Medicine; Nieca Goldberg, M.D., director, New York University Medical Center's Women's Heart Program, associate professor, New York University School of Medicine, and author, Dr. Nieca Goldberg's Complete Guide to Women's Health; March 27, 2008, presentation, Society for Gynecologic Investigation annual meeting, San Diego

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