A new study has found that women who use contraceptives face a higher risk of breast cancer, regardless of the type of birth‑control pill. Both progestin‑only and combined progestin‑estrogen contraceptives were linked to a modest increase in risk. The research, published in the open‑access journal *PLOS Medicine*, reported that the breast‑cancer risk was similar for combined and progestin‑only formulations.
The World Health Organization (WHO) notes that about half of breast‑cancer cases occur in women with no identifiable risk factor other than being female and over 40 years old. The WHO also lists several factors that raise breast‑cancer risk, including increasing age, obesity, harmful alcohol use, family history, prior radiation exposure, reproductive history, tobacco use, and postmenopausal hormone therapy.
In the new study, researchers from the United Kingdom used the Clinical Practice Research Datalink to examine medical records of 9,498 women under 50 who were diagnosed with invasive breast cancer between 1996 and 2017. A control group comprised 18,171 women without breast cancer. The investigators discovered that 44 % of the breast‑cancer cases had prescriptions for hormonal birth control, about half of which were progestin‑only. In the control group, 39 % had hormonal birth‑control prescriptions, also roughly half progestin‑only.
Dr. Parvin Peddi, a medical oncologist and director of Breast Medical Oncology at the Margie Petersen Breast Center, told *Healthline* that women do not need to choose progestin‑only contraceptives in hopes of a lower breast‑cancer risk. “We have known that oral contraceptives slightly increase the risk of breast cancer,” she said. “This study shows that the risk is similar across oral, injectable, and intrauterine progestin‑only options.” Peddi emphasized that the absolute increase in risk is very low—less than 0.5 % for women aged 35‑39 and even lower for younger users—and that the findings should not deter women from using hormone‑containing birth control.
Dr. Tola Kusimo, an oncologist at Federal Medical Centre in Abeokuta, cautioned that the study addresses only short‑term associations between hormonal contraceptives and breast‑cancer risk, not long‑term effects or the impact of total duration of use. He noted that while both combined and progestogen‑only contraceptives can slightly raise risk, the increase is minimal, especially in younger women. Kusimo recommended lifestyle measures—quitting smoking, maintaining a balanced diet, limiting alcohol, and keeping a healthy weight—to reduce cancer risk, adding that contraception offers many benefits alongside potential hazards unrelated to cancer.
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