Pregnancy may protect against bladder cancer

Pregnancy may protect women against developing bladder cancer later in life, according to scientists who conducted research on mice. The study by the University of Rochester Medical Centre attempted to understand why bladder cancer is three times more common in men than in women. Scientists in the past have put this down to historically higher smoking rates and dangers in the workplace for men, but the gap has existed even after women entered the workforce and took up smoking in greater numbers.

"While some researchers have asked why men are more vulnerable to bladder cancer, perhaps we should be asking why women have more protection," said study leader Dr Jay Reeder.

His research found that female mice that had got pregnant repeatedly had far less incidences of bladder cancer compared to their male counterparts as well as female mice that did not get pregnant.

"The mice that were pregnant nursed their offspring, and a protective effect could be related to pregnancy, lactation, or both. Additional studies are needed to identify the specific mechanism," said Dr Reeder.

In the UK, bladder cancer is the fifth most common cancer and around 10,000 people are diagnosed with it each year.

For men it is the fourth most common type of cancer, while for women it is the 11th most common.