The pill and cancer

Research shows a relationship between use of the contraceptive pill and a reduced risk of developing bowel, womb and ovarian cancer later in life.

You may have heard in the news about the contraceptive pill and the study which found that women who had used ‘the pill’ had a lower risk of getting cancer of the bowel, womb and ovaries many years after they had stopped taking the pill. On the other hand, the study also found that women had a higher risk of developing breast and ovarian cancer whilst they were ‘on the pill’. However, that increased risk seemed to be gone within 5 years after having stopped taking the pill whilst the ‘protective’ effect against bowel, womb and ovarian cancer lasted for perhaps more than 35 years after having stopped taking the pill.

One reason why researchers are interested in investigating the possible effects of the pill is that it contains hormones and certain cancers are known to be related to hormones, for instance breast cancer and ovarian cancer. This particular research is very important because it followed (collected information about) more than 46,000 women in the UK for up to 44 years. This is called a prospective cohort study because it collects data about a fixed group of people (cohort) from a certain point in time and follow them over time (prospectively).

These are good studies in showing what happens to the people in the study. So this study was able to tell how many of the women had developed various types of cancer and who hadn’t. Then they compared those groups and looked at whether women had used the pill and for how long and they looked at other factors too. However, this type of study is not able to prove that the reduced risk of developing cancer was actually caused by the fact that women had used the pill. There could be other factors in those women’s lives that had an effect of them developing cancer or not. Also, because the study started in 1968, the content (composition and dose of hormones) in the pill has changed over the years and women may also have used the pill differently than women do today. So this study can’t say for sure that the pills used today will have the same effect.

The most important finding of this study is that women who have used the pill in the past can be reassured that there is no evidence that it has increased their risk of getting cancer later in life. In fact, - in some cases it’s quite the opposite and there seems to be a protection against certain types of cancer.

You can read more about this study on the NHS Choices website.

This article was first published : 29.3.2017