Morning Sickness May Indicate Lower Risk of Breast Cancer

As peculiar as it seems, women who suffer through morning sickness during their pregnancies actually may be fortunate.

These women may have a 30 percent lower risk of developing breast cancer later in life than their seemingly fortunate counterparts that experience nine nausea-free months, a study by epidemiologists at the University at Buffalo suggests.

"Although the exact mechanism responsible for causing nausea and vomiting during pregnancy has yet to be pinpointed, it likely is a result of changing levels of ovarian and placental hormone production, which may include higher circulating levels of a hormone called human chorionic gonadotropin," said David Jaworowicz, Jr., first author on the study.

"In vitro studies have shown that this hormone possesses several activities that have potential protective effects against cancer cells," said Jaworowicz, a doctoral candidate in UB's School of Public Health and Health Professions.

Jaworowicz's research, which was presented June 25th at the Society for Epidemiologic Research's annual meeting in Boston, Mass., found no association of other pregnancy-related medical conditions -- pregnancy-induced hypertension, preeclampsia, gestational diabetes or weight gain -- and breast-cancer risk.

The study was based on data from participants in the Western New York Exposure and Breast Cancer Study; a population-based case-control study of breast cancer conducted in two Western New York counties between 1996 and 2001 in women aged 35-79.

The analysis compared extensive data on pregnancy-related conditions from 1,001 women with primary breast cancer and 1,917 women without breast cancer matched to cases by age and race that served as the study controls.

"Pregnancy is a time when the breast undergoes a variety of cellular and anatomical changes," said Jaworowicz. "During this period, the breast tissue is exposed to varying levels of a number of hormones, which may affect the physiology of the breast.