Morning sickness may protect against future breast cancer

In collaboration with the Press Association

Women who experience nausea and vomiting during their pregnancies may have a 30 per cent lower risk of developing breast cancer later in life than mothers-to-be who experience nausea-free pregnancies, researchers have said.

A new study by epidemiologists at the University at Buffalo looked at data from participants in the Western New York Exposure and Breast Cancer Study.

Researchers compared data on pregnancy-related conditions from 1,001 women with primary breast cancer and 1,917 women without breast cancer, all of whom were between the ages of 35 and 79.

Study author David Jaworowicz, a doctoral candidate at the university's Department of Social Preventive Medicine, presented the findings at the annual meeting of the Society for Epidemiologic Research.

He revealed that the stronger the symptoms of nausea and vomiting - or the longer they persisted - the lower the apparent risk of developing breast cancer later in life.

The researcher suggested that the effect may be the result of changing levels of ovarian and placental hormone production. This can include higher levels in the blood of a hormone called human chorionic gonadotropin, which studies show has a protective effect against cancer cells.

"Pregnancy is a time of drastic physiological changes, including rapid development and alterations in the breast tissue," Mr Jaworowicz explained.

"The rapidly changing anatomy of the breast makes it more susceptible to errors in DNA replication and/or repair, which may translate into breast cancer," he continued.

He pointed out that the levels of various hormones changes during pregnancy, and must be kept in a delicate balance. If the correct balance isn't achieved, then this can lead to conditions such as severe sickness.

"These pregnancy-related factors may serve as indicators of underlying biological conditions that may influence a woman's lifetime risk for breast cancer."

Mr Jaworowicz revealed that the researchers had also looked for a possible association between breast cancer risk and other pregnancy-related conditions, including hypertension, pre-eclampsia and eclampsia, gestational diabetes and high weight gain, but found no link with these other conditions.