The contraceptive pill reduces women's risk of developing womb cancer

Women who have used the contraceptive pill have a reduced risk of developing womb cancer and the longer they have taken the pill, the less risk they have of developing this type of cancer.

It has recently been reported in the news that women who have used the contraceptive pill have a reduced risk of developing womb cancer (also called endometrial or uterine cancer). This knowledge isn’t new though – earlier studies have also shown that the pill reduces the risk of womb cancer. However, this time researchers pooled together the results of many similar studies (this is called a meta-analysis) and that gives us a better overall picture of all available research in the area. By doing so, we can have more confidence in that the results are reliable and that we can trust them.

The researchers who did this meta-analysis pooled together data from 36 separate studies that had investigated if there was a link between using the pill and getting cancer up to 30 years after having used the pill. They looked at all the data in the 36 studies and compared women who had developed womb cancer with women who had not developed womb cancer and then checked whether women had ever used the contraceptive pill or not. And as usual in this type of research, the researchers also took into account other factors about the women that are known to affect the risk of developing cancer. If they hadn’t done that, we wouldn’t have been able to tell whether the increased risk of getting womb cancer was because of the pill or because of other things that might have increased the risk.

The researchers found that the longer women had used the contraceptive pill, the less likely it was that they developed womb cancer. For instance having used the pill for about 10 to 15 years had halved their risk of developing womb cancer. And it also showed that the risk reduction against womb cancer lasted for more than 30 years after women had stopped using the pill.

This study could only analyse data from women who had used what’s called the ‘combined oral contraceptive pill’ (the pill), which is the most common one that contains both the hormone oestrogen and the hormone progesterone. The results are not relevant to what’s called the “mini-pill”, which only contains the hormone progesterone. This is because there were too few women in the studies who had used the “mini-pill” so there was not enough data for the researchers to do a thorough analysis on those women.

You may want to know that most cases of womb cancer are diagnosed in women aged between 40 to 74. And although this research shows that using the pill can reduce the risk of developing womb cancer later on in life, it is important to remember that the pill has other risks and is not suitable for all women.

This research was carried out by a large group of researchers called the Collaborative Group on Epidemiological Studies on Endometrial Cancer and it was funded by the Medical Research Council and Cancer Research UK. You can read more about the study on the NHS Choices website.

This article was first published : 25.8.2015