The overall risk of cancer in women who use the birth control pill does not appear to be increased.

In fact, there is good evidence that certain cancers, most notably uterine and ovarian cancer, are decreased in women who use the pill. Some controversy remains about whether the pill increases the risk of breast and cervical cancer. If there is an effect, it appears to be very slight and has not been confirmed in all studies.

The Women's Health Initiative was a large study done to evaluate the risks of hormone therapy in women after menopause. It showed a higher risk of breast cancer in women who used estrogen and progesterone together for more than four years.

However, it is important to note that menopausal women are biologically different from women who take the pill for birth control and the doses of hormone used are not the same. We cannot assume that the hormone effects in these different groups will be the same and studies suggest that this is the case.

Some oral contraceptive pills contain estrogen and progesterone. In this case, it is difficult to separate the effects of one hormone or the other.

The studies on the progesterone only pill are reassuring. They suggest there is no significant increase in breast cancer risk. There are other potentially dangerous but rare effects of hormone contraceptives. These risks include blood clots and heart disease.

The decision to use the pill should be made after you and your doctor carefully consider the risks and weighed them against the benefits of reliable contraception.