March 4, 2004 -- Recent research suggests that women with a history of preeclampsia may be at increased risk for heart disease and stroke later in life. Now a newly released study shows that the same may be true for certain cancers.
In the population-based study from Israel spanning three decades, overall cancer risk was modestly elevated among women with a history of the pregnancy complication. Preeclampsia occurs in 5%-8% of pregnancies and is characterized by extremely high blood pressure that is diagnosed during pregnancy and threatens the life of the mother or her baby.
Previous studies examining the link between the condition and later cancer risk have been mixed, with some suggesting that women who have had preeclampsia are protected from certain cancers and others showing the opposite or no association.
"The prior research does not indicate a strong link one way or the other, and that is certainly true of our study," lead researcher Ora Paltiel, MD, of Jerusalem's Hadassah Hebrew University, tells WebMD. "I would characterize this as a weak association. Overall there was less than a twofold increase in risk, which is not very large."
Paltiel and colleagues followed roughly 40,000 women who gave birth between 1964 and 1976 in West Jerusalem, Israel for roughly 30 years following their deliveries. They did this by comparing a comprehensive birth registry with a national cancer registry.
Overall cancer incidence was slightly elevated among women with a history of preeclampsia, with the highest risk seen among those followed from their first pregnancy. Compared with women who had never had preeclampsia, cancer risk was 1.5 times greater for these women. Significant increases in risk were reported for cancers of the breast, stomach, ovary, lung, and kidney. The findings are reported in the March 6 issue of the British Medical Journal.
If the association is confirmed, Paltiel says the next step is to identify the biological influences behind it.
"It has been suggested that folate deficiency may be involved in both preeclampsia and cancer risk or that genetic influences may explain the association," she says."
University of Virginia epidemiologist Kim Innes, PhD, says risk may also be influenced by a woman's age. In a 1999 report, Innes concluded that a history of preeclampsia seemed to protect women who gave birth later in life against breast cancer, but the association was not as strong for younger women.
"It makes sense that hormonal changes during pregnancy, and conditions like preeclampsia which affect these changes, would influence a woman's later health," she tells WebMD, adding that researchers are just beginning to understand the long-term impact of these hormonal changes.