Increased Risk of Breast Cancer Due to Contraceptive Pills

Contraceptive pills may lead to increased breast cancer risk. Image source: Continental hospitals.

According to a new study conducted by the University of Michigan, contraceptive pills can lead to an increased risk of breast cancer. The study finds that a few frequently prescribed contraceptive pills can double the level of synthetic estrogen and progesterone hormones.

Today, most of the women across the globe prefer consuming contraceptive pills to avoid pregnancy but, it can make you a susceptible to increased risk of breast cancer.

Globally, there are two types of contraceptive pills:

  • Combined oral contraceptive – It is the most commonly used one and it consists of the synthetic female hormones (estrogen and progesterone)
  • Minipill – It consists of only progestin, a synthetic version of progesterone which is used in oral contraceptives.

In a post published by the National Cancer Institute,  Nurses’ Health Study has carried out a survey of nearly 1,16,000 nurses, between 24-43 years-old. found out that these pills increase the risk of breast cancer. Moreover, the increased risk was attributed to a  ‘triphasic pill’ wherein the hormone dosage changes over three stages. The women in this group experienced a higher risk of breast cancer than the others.

It is believed that the women who consume contraceptive pills have a higher amount of hormone present in their blood when compared to the women who do not consume these pills.

Contraceptive pill blister pack
Contraceptive pills may increase your risk to breast cancer. Image credits: Ian Prythearch

The increasing estrogen and progesterone hormones can stimulate the growth of breast cancer. This is one of the reasons that most of the patients are advised to undergo hormone therapy in order to block the effect of such hormones on cancer cells.

Human evolutionary biologist, Beverly Strassmann says, “Birth control has greatly improved the lives of women. But it is also necessary to design these pills in such a way that it does not increase the risk of breast cancer.


Progesterone and Oestrogen are produced by the ovaries and the amount of their production varies naturally, after the menstrual cycle. The birth-control replaces these naturally produced hormones with the synthetic versions.

Strassmann states that there is a direct connection between the contraceptive pills and the risk of breast cancer. She extracted data from 12 various studies which measure the amount of oestrogen and progesterone over the menstrual cycle in women who do not take these pills. The study is a continuation of her previous research on menstruation and reproductive biology among the Dogon people of Mali in Western Africa.

According to the Cancer research in the UK, around 1% of breast cancers in women are caused due to the oral contraceptives. Though it protects you against various other cancers such as ovarian or any health issue related to the womb, there is still a presence of increased breast cancer risk.

You can read the original study here.


Source University of Michigan Oxford Academic

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