‘Another benefit’: The pill shown to reduce ovarian cancer risk

The oral contraceptive pill (OCP) could play an important role in reducing ovarian cancer risk, with a 26% reduction for women who have ever taken it, and 43% for those who have taken it after the age of 45. 
 
That is according to new research from the University of South Australia (UniSA), which conducted screening of 221,732 women without a history of cancer in the United Kingdom’s biomedical database, Biobank, for risk factors of the cancer.
 
Understanding risks and preventive factors for ovarian cancer is key for improved treatment and outcomes, the UniSA researchers highlight, and interventions that reduce the number of ovulations have the potential to be used as targeted prevention strategies. 
 
Professor Danielle Mazza is the Head of General Practice at Monash University and Chair of the RACGP’s preventive health guidelines, the Red Book.
 
She told newsGP the research adds to the ‘copious amount’ of literature that indicates there are ‘significant benefits’ to the use of hormonal contraceptive products.
 
‘Reducing ovarian risk is one of them – it’s something we’ve known from previous studies, but this quantification is helpful,’ Professor Mazza said.
 
‘Women are being bombarded at the moment with misinformation about hormonal contraception, and it’s leading to an increasing trend away from hormonal contraception with the belief that this is best for women.’
 
The research also suggests that having more previous pregnancies that resulted in a birth, or ‘greater parity’, and ever-use of OCPs were both associated with lower ovarian cancer risk.
 
Women who had given birth to two or more children had a 39% reduced risk of developing ovarian cancer compared to those who had not had children. 
 
Professor Mazza said women’s menstrual cycles have evolved in recent decades, meaning the detection and diagnoses of diseases must also shift.
 
‘This concept that it’s natural to have a cycle every month is kind of erroneous,’ she said.
 
‘In the past women used to be pregnant all the time or breastfeeding, so didn’t have many cycles. But in modern life where women are achieving menarche at an earlier age, and menopause at the average age of 51 and having fewer children, if any, the number of cycles that a woman has throughout her lifetime is quite different to how it was in years gone by.
 
‘This might be one of the contributing factors to the higher risk of these kinds of cancers.’
 
At the start of the UniSA study, launched in 2021, information from a diversity of health-related characteristics were measured, including medication use, diet and lifestyle, physical measures, metabolic and hormonal factors.
 
Biomarkers linked with increased ovarian cancer risk were identified, including greater height, weight, and red blood cell distribution. Meanwhile, higher levels of the liver enzyme aspartate aminotransferase in the blood were associated with lower risk.
 
Study co-author Professor Elina Hyppönen said it is ‘exciting’ to see the data-driven analyses revealing risk factors for the cancer to drive early action.
 
‘It is possible that by using the OCP to reduce ovulations or by reducing harmful adiposity, we may be able to lower risk of ovarian cancer,’ she said.
 
‘But more research is needed to establish the best approaches to prevention, as well as the ways in which we can identify women most at risk.’
 
Using artificial intelligence analyses to inform prevention and early detection of the deadly cancer, the research comes as World Cancer Day on 4 February aims to raise better awareness.
 
In Australia, an estimated 1786 new cases of ovarian cancer were diagnosed in 2023, with an estimated 1070 related deaths in 2024.
 
Ovarian cancer, including carcinomas of the fallopian tube, accounted for around 26% of all gynaecological cancers diagnosed in 2024, and are estimated to account for 48% of the 2240 deaths from gynaecological cancer in that year.
 
Professor Mazza said the UniSA researchers have added to the existing evidence of the many benefits of the OCP.
 
‘It’s good to see this research coming out, and more women should hear about the benefits of being on the pill,’ she said.
 
‘These include things like less iron deficiency, less anaemia, less period pain, management of endometriosis, management of polycystic ovarian syndrome, management of PMDD, so many things that we can use the hormonal contraception for therapeutically.
 
‘And this research is evidence of another helpful benefit.’
 
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cancer risk oral contraceptive pill ovarian cancer preventive health women’s health