All about the birth control pill

A pack of birth control pills

The benefits and risks of hormonal birth control

The birth control pill has been used in Canada since the 1960s. Today, it’s one of the most popular forms of birth control in Canada and the United States. More than 15% of women aged 15 to 49 use it.

A pack of birth control pills

How does the pill work?

The most commonly prescribed birth control pill contains synthetic versions of 2 female hormones – estrogen and progesterone. The hormones work together to prevent pregnancy by blocking the release of eggs from the ovaries.

What are the benefits of the pill?

The major benefits of taking hormonal contraceptives are:

  • preventing unwanted pregnancy
  • reducing the symptoms of menstruation (for example, cramps and bleeding)
  • reducing the risk of uterine and ovarian cancers
  • managing the side effects of excessive male hormone production (for example, acne and unwanted hair growth)
What are the risks of the pill?

Women who take the pill have a slightly higher risk for breast, cervical and liver cancers. They also have a higher risk for heart disease and stroke (mostly in women who smoke).

Other types of hormonal birth control

Birth control methods like the patch, vaginal ring, skin implant and injection also change a woman’s hormone levels. They’re newer, so there’s not enough research yet to know how they affect cancer risk.

Our perspective

The Canadian Cancer Society believes it’s important to understand the benefits, risks and side effects of birth control pills and other hormonal contraceptives so women can make an informed decision about their own health.

Women who are considering hormonal contraceptives should talk to their doctor about the benefits and risks, their personal and family health history and other medical concerns.

Does the pill increase your risk of cancer?

Research shows that women who use the birth control pill have a slightly increased risk of breast, cervical and liver cancer.

The pill and breast cancer risk

Women who use the birth control pill may have a small increased risk of breast cancer. The risk is smaller for women who used the birth control pill after their first full-term pregnancy.

The pill and cervical cancer risk

The risk appears to be greater for developing early stage cervical cancer than it is for more advanced forms of the disease.

The pill and liver cancer risk

Women who took birth control pills for more than 5 years before doses and formulas changed may have a slightly higher risk of developing liver cancer.

The pill may reduce your risk of 2 types of cancer

The birth control pill has been shown to decrease the risk of uterine and ovarian cancers.

The pill and uterine cancer

The protective effect appears to last for at least 15 years after stopping the pill.

The pill and ovarian cancer
The longer a woman uses the birth control pill, the lower her risk of developing ovarian cancer seems to be. The protective effect appears to last at least 20 years after stopping the pill.