The International Agency for Research on Cancer’s reclassification of combined contraceptive pills containing oestrogen and progestogen as Group 1 cancer-causing factors has renewed concerns about their safety, after posts by some medical content creators presented the classification as meaning that every woman who takes these pills will develop cancer.
The agency’s classification does not determine the risk for every user
However, medical data in health institutions’ reports present a more complex relationship, with risks and benefits varying according to the type of cancer and the woman’s health. The agency, which is part of the World Health Organisation, placed these pills in Group 1 in May 2026 and noted an association with breast and cervical cancer.
At the same time, it cautioned that its assessment did not cover a number of factors not examined in the agency’s research, including genetic and reproductive characteristics, a woman’s health, and some dietary factors. The classification does not determine the likelihood of cancer for every user or mean that the disease is an inevitable result of taking the pills.
The agency’s monitoring of this issue dates back to 2007, when it published a report on the potential side effects of some combined contraceptives containing the hormones oestrogen and progesterone. It identified types of cancer whose risks could rise or fall among users of these methods, without the report providing an individual estimate of each woman’s likelihood of developing cancer.
Amr Hassan warns against turning the classification into panic
Dr Amr Hassan, professor of obstetrics and gynaecology at Cairo University’s Faculty of Medicine and a member of the World Health Organisation’s technical advisory group on estimating maternal deaths and their causes, said the debate over the classification of some hormonal contraceptives and their relationship with cancer highlighted an issue extending beyond the interpretation of a scientific term. It concerned how medical information is conveyed to women without concealing the risk or turning it into a cause for panic.
Hassan explained that the agency’s classification of some combined hormonal contraceptives did not mean that all women who use contraceptive pills would inevitably develop cancer.
An association between these methods and an increased risk of certain cancers does not negate their association with a reduced risk of others, particularly ovarian and endometrial cancer. He noted that research into the link between oral contraceptives and cancer had continued for decades, so its findings could not be reduced to an absolute judgement that the pills either “cause cancer” or “do not cause cancer”.
The benefits of the pills vary according to the type of cancer
Interpreting the data requires consideration of the type of tumour, duration of use, medical and family history, and each woman’s specific health factors. Reports issued by the World Health Organisation in December 2025 showed that the benefits of some contraceptive pills extend beyond preventing pregnancy.
These methods may reduce the risk of uterine and ovarian cancer, and may also ease anaemia, menstrual pain, bleeding problems and ovulation pain, as well as some symptoms of polycystic ovary syndrome and endometriosis. The organisation describes the relationship between combined oral contraceptive pills and cancer as complex.
On the one hand, these pills help protect against ovarian and endometrial cancer, with their protective effect becoming stronger the longer they are used. On the other hand, users of oral contraceptives are more likely to develop cervical cancer than women who do not use them.
Regarding breast cancer, World Health Organisation data indicate that most women do not face an increased risk, while the risk may rise among women carrying inherited genetic mutations, particularly with long-term use. This variation highlights the importance of not applying a single risk estimate to all users without taking each case’s health and genetic characteristics into account.
US data compare breast, uterine and ovarian cancer risks with long-term pill use for cancer prevention and warn of individual differences in
In an analysis cited by the US National Cancer Institute, covering data from more than 150,000 women who took part in 54 epidemiological studies, women who had previously taken oral contraceptives recorded a slight 7% increase in their risk of breast cancer compared with those who had never used these methods.
The increase in risk reached 24% among women who were using oral contraceptives when the studies were conducted. The data showed no rise in this percentage with longer use. The risk fell after women stopped taking the pills, and no increased risk of breast cancer was recorded 10 years after they stopped using them.
By contrast, the institute’s data showed that women who had previously used oral contraceptives were less likely to develop endometrial cancer than women who had never used them. The reduction in risk was at least 30%, with the protective effect increasing the longer the pills were taken.
This protective effect does not end when oral contraceptive use stops: the reduced risk of endometrial cancer continues for years after women stop taking them. The finding shows that assessing the pills involves not only the risks that may accompany their use, but also health benefits that can extend beyond it.
The difference between an increased risk of some cancers and a reduced risk of others explains the World Health Organisation’s emphasis on the need for personalised medical advice when choosing contraceptive methods.
This advice should take into account the woman’s medical history, family history and risk factors, rather than relying on a general classification as an individual judgement that applies in the same way to all women. A mass decision to stop using contraceptive pills out of fear of cancer could create health and social risks.
The World Health Organisation says oral contraceptives are among the most effective methods of preventing unintended and high-risk pregnancies. They also represent a public health achievement because of their role in improving women’s health, reducing maternal deaths, and supporting access to education, work and economic opportunities.
Hassan warned that abruptly stopping an effective contraceptive method on the basis of a post circulating on social media might not be a sound health decision. He explained that the decision was not linked to the medicine alone, but to the woman using it and her health and reproductive circumstances, saying: “There is no contraceptive method that is ideal for all women, but there may be a method suitable for this woman at this stage of her life”.
He added that the choice of contraceptive method should be based on medical history, risk factors, age, health status and reproductive needs, alongside the woman’s wishes and preferences after she had received accurate medical information. He stressed that the doctor’s role was not to make the decision for the woman, but to provide her with the information to help her make an informed choice suited to her circumstances.
Some health conditions may make certain hormonal methods unsuitable. Hassan gave the example of current breast cancer, explaining that this condition requires a different assessment and the selection of other methods in accordance with medical guidelines. This means that contraceptives should be considered through an individual assessment, not a uniform decision to use or stop using them.
Hassan believes that family planning is not limited to reducing the number of births, but is part of women’s health and the family’s right to choose when to have children and to space births. Modern family planning, he said, is based on a range of methods, high-quality counselling and the availability of alternatives, allowing every woman to choose the method suited to her health and reproductive circumstances.
He warned that providing incomplete medical information could carry a health cost, particularly if it led a woman to stop using contraception without a suitable alternative being provided. Classifying some pills as cancer-causing factors does not mean ignoring potential risks, nor does it make developing the disease inevitable. Rather, it calls for an individual balancing of benefits and risks and a decision made in consultation with a doctor.
