Several factors, such as older age and high weight gain, are known risk factors for pre-eclampsia and other pregnancy-related blood pressure disorders.
Now a new report suggests that social factors - including living in a rural county - may also increase the risk of pre-eclampsia and pregnancy-induced hypertension (PIH), according to research being presented at the American Society of Nephrology's 41st Annual Meeting and Scientific Exposition in Philadelphia, Pennsylvania.
"Our study showed an increased risk of developing pre-eclampsia and PIH associated with living in a rural area," comments lead researcher Rebecca Moore, MD, of the University of Colorado Health Sciences Center in Denver, Colorado. "The reason for this increased risk is unclear, but may possibly be associated with maternal poverty and social deprivation."
Using birth certificate data on infants born in Colorado from 2000 to 2006, the researchers analyzed risk factors for pre-eclampsia and PIH in more than 362,000 mothers. All of the women were free of chronic medical conditions at delivery. Women with pre-eclampsia develop rapid increases in blood pressure, along with kidney damage. Pre-eclampsia is a very common condition and the third most common cause of maternal death in the United States. The cause is unknown and there is no known cure, although the problem usually resolves after delivery.
The overall rate of PIH/pre-eclampsia was 3.3 %. The study confirmed the known risk factors, including age over 35 years, first pregnancy, multiple gestation (twins or more), and gaining more than 30 pounds during pregnancy. Smoking was associated with a lower risk of pre-eclampsia (but smoking increases the risk of other pregnancy complications).
After adjusting for all of these factors, the researchers identified some intriguing new risk factors for PIH/pre-eclampsia. Women living in rural counties were at increased risk: 56 percent higher than for women in other areas.