The fascinating way the Pill and pregnancy can reduce your ovarian cancer risk.

I was reading about Noa Popovsky, a 34-year-old who has lost her reproductive organs, her spleen, and parts of her liver and her colon to ovarian cancer – the deadliest type of gynaecological cancer.

“Like many women, I used to be a full time working mother, busy looking after my kids, husband, house and never really stopping,” Popovsky told The Telegraph.

“Now, I have been forced to stop and it makes everything sweeter. I appreciate every moment.”

The mother of two is currently receiving treatment after her second relapse and, in Australia, there are many women in a similar situation.

This year, it is estimated 1,580 females will be diagnosed with ovarian cancer. Their chance of surviving five years is around 44 per cent. Also this year, ovarian cancer will take the lives of 1,047 Australian women.

Like most cancers, the chances of surviving ovarian cancer increase the sooner it is diagnosed. But – with symptoms that are difficult to identify and easily explained as something else – diagnosis is often a problem and around 70 per cent of cases diagnosed are already at the late stages of stage three or stage four.

In Noa’s case, for example, she suffered six months of low level back pain and bloating before she was told she had stage four ovarian cancer. She had been misdiagnosed twice by different doctors who told her it was a urinary tract infection.

The key is prevention.

Reading about Noa, I discovered both taking the contraceptive pill and childbirth can reduce a woman's risk of ovarian cancer. What?

It is not something I have read or heard about before and, when I stumbled across this helpful and promising and why-don't-I-know-this-and-how-many-other-people-are-also-unaware nugget of information, I decided to find out more.

Speaking to Melbourne obstetrician, gynaecologist and IVF specialist, Dr Joseph Sgroi, I learned there are three factors that can reduce a woman's risk of ovarian cancer.

Taking the Pill

Joe tells me that yes, taking the Pill does reduce a woman's risk of ovarian cancer. He also pointed me to a recent analysis of 45 epidemiological studies from 21 countries to make sure I believed him.

The analysis found any use of oral contraceptives is associated with a significant reduction in risk of developing ovarian caner.

Relative risk drops by around 20 per cent for each five years of use. And, after 15 years of taking the pill, the risk of developing ovarian cancer is reduced by up to 50 per cent.

"That means your chances go from one in 70 women who will be diagnosed with ovarian cancer, to one in 140 women," Joe says.

Giving birth

Full term pregnancy is also associated with a decreased risk of ovarian cancer.

Another study found women with at least one full-term pregnancy have a significantly reduced risk, compared to women who haven't had children or who've miscarried early in their pregnancy.

For every pregnancy after the first, the risk continues to drop by a further eight per cent.

"As well as this, women who fall pregnant over the age of 35 have additional increased protection against ovarian cancer," Joe says.

Listen: Tina Harris reflects on her experience with breast cancer. Post continues below.

Breastfeeding

Again, women who've breastfed have a reduced chance of developing ovarian cancer, compared to women who haven't.

The longer you breastfeed, the lower your relative risk becomes.

Research has found women who breastfeed for less than six months experience a 17 per cent reduced risk of developing ovarian cancer. Those who breastfeed for between six and 12 months have a 28 per cent lower risk.

But... Why?

No one knows for sure but there is a pretty solid theory around why these three factors all contribute to a decreased risk of developing ovarian cancer.

"Pregnancy, the Pill and breastfeeding all lead to a nonovulatory state, and we think this is what creates the protective effect," Joe says.

So why is nonovulation good for the ovaries, and why constant ovulation a little more risky?

"A regular menstrual cycle means a continual turnover of cells in the ovaries. Cancers are formed when the turnover of cells becomes disorganised," Joe says. "If you can somehow stop continual turnover - like with the contraceptive pill, childbirth and breastfeeding - it's postulated that your risk of developing ovarian cancer is reduced."

"When you're pregnant, your period stops. These women sometimes go onto breastfeed, and during breastfeeding women do not have menstrual periods," he continues.

"It's the same with the Pill, which prevents ovulation. Even when you take the sugar pills and you're 'bleeding', you aren't ovulating and it's not a natural period."

Symptoms of ovarian cancer include persistent abdominal pain, bloating, difficulty eating and a frequent need for urination.

While regular scanning is not available, Joe encourages women to "go seek advice early if you are experiencing irregular bleeding, abnormal bloating and pain in your pelvis".