Having babies reduces ovarian cancer risk

Women’s risk of developing ovarian cancer is significantly reduced by having a baby, and the risk drops further still for each subsequent child a mother gives birth to, a new study has found.

Data collected from 8,000 women with ovarian cancer as part of the UK Million Women Study has revealed that women who give birth to one child have about a 20 percent reduction in risk compared to women who do not have children, and their risk of developing endometrioid and clear cell tumours is 40 percent lower.

Women who have more than one child are even less likely to develop ovarian cancer, with each subsequent baby delivering an estimated eight per cent reduction in overall risk.

But while the findings at first glance seem to suggest that having bubs is an actionable cancer deterrent, it’s not that simple. The researchers also looked at women who had had their fallopian tubes cut or clipped surgically (called tubal ligation or sterilisation), which provides a permanent means of contraception.

Women who underwent this procedure also had a 20 per cent lower overall risk of ovarian cancer, providing further evidence that the causes of ovarian cancer are more complex than it was once believed.

“In the last few years, our understanding of ovarian cancer has been revolutionised by research showing that many cases may not in fact come from the ovaries,“ said Kezia Gaitskell from the Cancer Epidemiology Unit at the University of Oxford and lead researcher on the study. “For example, many high-grade serious tumours — the most common type — seem to start in the fallopian tubes, while some endometrioid and clear cell tumours may develop from endometriosis.”

The findings, which were presented at the 2015 National Cancer Research Institute conference in the UK this week, don’t necessarily mean that choosing to have more children will protect you from cancer, but statistically speaking, women who have more children are less at risk.