Are progestogen-only contraceptives safe for women to use?

UK research suggests that women taking progestogen-only contraceptives have an increased risk of breast cancer, with older women more at risk. But the odds of getting breast cancer are still fairly small. 

What is the research about? 

Whether progestogen-only contraceptives increase women’s risk of breast cancer.  

The research involved around 28,000 women in the UK and other high-income countries.  

Why is this research important? 

Studies have found that women who take the combined contraceptive pill (which contains progestogen and oestrogen) have a slightly higher risk of breast cancer than other women. But research has been missing on whether women who take the progestogen-only pill (also known as the mini pill) or other progestogen-only contraceptives, such as injections, also have an increased risk of breast cancer. This is the first major study to assess this. 

What did they find out? 

Women using progestogen-only contraceptives (pills, injections and the coil) have an increased risk of breast cancer. This risk is similar to the increased risk caused by the combined contraceptive pill. 

Taking progestogen-only contraceptives for five years increased a woman's chance of developing breast cancer within the next 15 years by 20-30%, depending on age.  

Among women aged 16 to 20 this means 8 extra breast-cancer cases happened for every 100,000 women. Among women aged 25 to 29, there were 61 per 100,000 extra cases, and for women aged 35 to 39 there were 265 extra cases. 

The increased risk of breast cancer was cancelled within a few years of a woman stopping progestogen-only contraception.  

What does this mean for reproductive health services? 

It is important to be aware of this study. It may cause some women to have concerns about taking progestogen-only contraception. 

It is important to let women with these concerns know that the risk of breast cancer is still very small and should be weighted up against the benefits. When taken properly, the progestogen-only pill is 99% effective at preventing unplanned pregnancies. It is also a good alternative for women who are breastfeeding or are at risk of blood clots. Like other hormonal contraceptives, progestogen-only contraception lowers women’s risk of womb and ovarian cancer. 

Eating a healthy diet and not drinking too much alcohol are things that women can do to reduce their risk of breast cancer. It is important to highlight this to women who are worried and emphasise that doing these things will be more effective at reducing breast cancer risk than changing contraceptives. However, if women are older or have a history of breast cancer in the family it is worth discussing alternative contraceptive options with them.