Can Preeclampsia Cause Cancer?

Study sees possible link between the blood pressure problem and some types of tumors

THURSDAY, March 4, 2004 (HealthDayNews) -- Women with a history of preeclampsia may have a higher risk of developing cancer, especially cancers of the stomach, breast, ovary, lung and larynx, a new study says.

The findings, while preliminary, suggest there might be some common environmental or genetic factor undergirding both preeclampsia and cancer.

The authors of the study, which appears in the March 6 edition of the British Medical Journal, stress, however, that there's no reason for women to panic.

Preeclampsia, a condition that occurs during pregnancy, is marked by high blood pressure and the presence of protein in the urine. It can cause a host of problems, even death, for both the mother and the fetus.

Previous studies have shown either no association between preeclampsia and cancer or have indicated that the former may actually protect against the latter. Most of the studies that showed a protective effect were done among European or North American women.

The scientists behind the new study conducted their research in Israel, looking at 37,033 women who had delivered babies at three large hospitals in West Jerusalem between 1964 and 1976. The median follow-up time was 29 years.

Women who'd had preeclampsia appeared to have about a 30 percent increased risk of cancer in general, compared with women who had not developed the condition during pregnancy. The risk of breast cancer was almost 40 percent higher. The risk for stomach, ovarian, lung, and laryngeal cancer was also increased, according to the study.

While it's well known that Ashkenazic (European Jewish) populations are at a heightened risk of breast and ovarian cancers because of gene mutations, only one-third of the women in the new study belong to that group.

One potential limitation of the study is that it did not account for smoking because the relevant information was missing for half the participants.

The question of why there might be a relationship between preeclampsia and cancer remains unanswered, the study authors say.

"We studied an epidemiological association and can only speculate about the mechanism behind our findings," says Dr. Ora Paltiel, lead author of the study and a senior lecturer at the Braun School of Public Health and Community Medicine at Hadassah-Hebrew University in Jerusalem.

"We might theorize that factors related to cancer may be operating in preeclampsia and vice versa," Paltiel adds. "These might include diet (such as folate deficiency), angiogenesis (new blood formation) and thrombosis (blood clotting). Some genes may be common to both cancer and preeclampsia development. There is also the possibility that some of our findings are due to chance, given the small number of cases at some sites."

The findings will need to be confirmed in other studies and in other populations, Paltiel says.

"I would stress that although the findings are statistically significant, the size of the risk is small and women should not be alarmed by the findings," she says. "Rather, scientists should be challenged to confirm the findings and try to determine the mechanisms."

More information

For more on preeclampsia, visit the Preeclampsia Foundation. Check with the American Cancer Society for more on different forms of cancer, including breast cancer.

Ora Paltiel, M.D., senior lecturer, Braun School of Public Health and Community Medicine, Hadassah-Hebrew University, Jerusalem, Israel; March 6, 2004, British Medical Journal
Consumer News