South African women who use injectable or oral contraceptives are 1.7 times more likely to develop breast cancer than others.
But that risk vanishes a decade after they stop taking hormonal contraceptives.
These are among the main findings of an expert study led by Margaret Urban, a medical scientist at the National Health Laboratory Service, which investigated the relationship between using oral and injectable hormonal contraceptives and cancers of the breast, cervix uteri, ovary and endometrium at public hospitals in Joburg.
In SA more black women use contraceptive injections than the pill.
“Yes, your risk goes up if you’re using either the pill or injection, but as soon as you stop, that risk diminishes,” said Urban, of the Medical Research Council’s cancer epidemiology research group..
“We don’t know the exact timing. But 10 years after you stop, your risk is back down to the background risk.”
Urban said that for any cancer there were many risk factors like weight and alcohol.
But while there were increased risks with some cancers, like breast and cervical cancer, contraceptive use reduced the risk of others like ovarian and endometrial cancer.
“The contraception is protecting you from unwanted pregnancy so you have to balance the protection you are getting against the other risks,” Urban said.
“Certainly it’s no major risk. It’s adding something less than 20 percent of your total risk. But obviously if a woman comes from a family where a lot of women have had breast cancer and there is inherited risk, then you may not want to take hormonal contraceptives.”
The research is published in medical journal PLoS Medicine.
And while oral contraceptives are known to influence the risk of cancers of the female reproductive system this is the first significant study on injectable contraceptives especially because of its widespread use.
This study will contribute to the Medicine Control Council’s guidelines for women’s contraceptive use. - Independent on Saturday