A new study is showing the link between the use of birth control to increased risk of breast cancer. A woman's risk went up the longer she used hormonal birth control, the study found. Know also that the study found the risk stays higher for about 5 years after stopping the pill, so if you're age 40 or older, hormones may not be the best choice.
The study is published today (Dec. 6) in The New England Journal of Medicine.
But here's the good news: the risk is really not all that much, and certainly much lower than the risk in decades past.
The study offered a look at the effects of modern birth control use, over a long period of time, in a large group of women. Therefore, it wasn't clear if this risk applied to newer formulations of birth control pills or to other birth control methods, including intrauterine devices (IUDs) and implants that contain only the hormone progestin.
"These results do not suggest that any particular preparation is free of risk", he wrote in the editorial.
Hormonal contraception should still be perceived as a safe and effective option for family planning.
Researchers followed more than 1.8 million women for an average of eight years. The researchers used nationwide registries to collect information about prescriptions that were filled for hormonal contraception, as well as diagnoses of breast cancer.
Obesity has always been known to increase the risk of some cancers and scientists believe that weight could overtake smoking as the single biggest avoidable cause of the disease. Around 50,000 women are diagnosed with breast cancer each year - with 12,000 dying. The risk for getting breast cancer was 9 percent higher for women who used birth control for less than one year and 38 percent higher for those who used it for more than 10 years.
Dr. Dona Hobart, medical director of the Center for Breast Health at Carroll Hospital, said that women have to make a similar decision when deciding whether to take hormone replacement therapy, which also can increase the risk for breast cancer. But if they had taken hormonal contraception for more than five years, the higher risk of breast cancer persisted for at least five years after their discontinuation of hormonal birth control, the study found.
Hunter also adds that the persistent risk found in the study "should be regarded as preliminary", with the increase unlikely to be significant when other factors, such as different durations of use and time since last use, are accounted for.
In a commentary that accompanies the study, David Hunter, a professor of epidemiology and medicine at the University of Oxford, stresses that the breast-cancer risks identified in the current study need to be balanced with the health benefits associated with hormonal contraceptives.