Now, research being presented at the 13th World Congress of the International Society for the Study of Hypertension in Pregnancy by scientists from the Magee-Womens Research Institute and the University of Pittsburgh School of Medicine suggests that the risk of preeclampsia may actually decrease if a woman smokes, but that the negative effects of preeclampsia may persist even though the condition itself is not present in a later pregnancy.
"Research is closing in on this menace," said James M. Roberts, M.D., professor and chairman of research in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine, director of the Magee-Womens Research Institute and president of the International Society for the Study of Hypertension in Pregnancy. "But there is still much to do."
By comparing the uric acid concentrations in blood samples between women with normal pregnancies including smokers, nonsmokers and women who had quit smoking during pregnancy, Kristine Yoder Lain, M.D., assistant professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine, and her colleagues found elevated levels of uric acid in smokers. But the highest rate of increase was found among women who had quit smoking at the onset of pregnancy, suggesting that smoking may actually decrease the risk for preeclampsia. Many other adverse health effects remain for both women and their babies, however, when a woman continues to smoke during pregnancy.
Dr. Lain and her colleagues also compared pregnancy outcomes among women who had preeclampsia early or late in a previous pregnancy, as well as among women who did not develop the disorder. The researchers found that women who experienced preeclampsia early in pregnancy tended to deliver smaller infants, and to deliver them earlier in subsequent pregnancies even though they did not develop preeclampsia again.
These results may indicate that abnormal implantation of the fertilized egg in the uterus - a possible cause of preeclampsia - may persist even in the absence of clinical preeclampsia.
Women who have previously experienced preeclampsia, also known as toxemia and characterized by high blood pressure, swollen ankles and the presence of protein in the urine, have an even greater chance of developing the disorder in subsequent pregnancies. Other risk factors include maternal age of less than 25 or more than 35 years and preexisting hypertension, diabetes or kidney disease.
"Preeclampsia is one of the leading causes of maternal, fetal and neonatal disability and death," said Dr. Roberts.
Magee-Womens Research Institute, the country's first institute devoted to women and infants, was formed in 1992 by Magee-Womens Hospital of the UPMC Health System. The University of Pittsburgh School of Medicine's department of obstetrics, gynecology and reproductive sciences is one of the top three funded departments by the National Institutes of Health.
Note to editors: To arrange an interview with Drs. Roberts or Lain, please call Michele Baum or Kathryn Duda at 412-647-3555.