The contraceptive pill protects women against some types of cancer for up to 35 years after stopping it. These are the conclusions of the longest study of health risks to date.
There have been voices for several years that the combined pill increases the risk of cancer, but a recent study by scientists at the University of Aberdeen in Scotland has found that the pill is in fact surprisingly effective at protecting against ovarian, endometrial and colon cancer.
Although there was a slight increase in the likelihood of developing breast and cervical cancer, the study showed that the risk returns to normal several years after stopping the pill.
The British Royal College of Family Physicians initiated a research program in 1968, seven years after the birth control pill was introduced to the UK market. 46 women participated in the program, which lasted for nearly half a century. Some of the patients were monitored for over 40 years.
An analysis of data collected over several decades has shown that the use of oral contraception – no matter how long – reduces the risk of colorectal cancer by 19%, endometrial cancer by 34%, and ovarian cancer by 33%.
This means that every third woman who can develop ovarian or endometrial cancer can feel safe because she uses oral contraception. In colorectal cancer, the pill protects one in five women. In the UK, 35 women are diagnosed with these three cancers each year. ‘The conclusions of the longest-to-date study of the effects of oral contraception on women’s health are very encouraging,’ comments Dr Lisa Iversen, who led the study.
– The results confirm beyond any doubt that most women using oral contraception do not risk cancer, on the contrary, the pill protects many of them against cancer. Since the study was conducted over several decades, we were able to look at what effects the use of oral contraception can have in the long run, adds the researcher.
Taking the pill does not appear to increase the risk of cancer over the course of a lifetime, and for several types of cancer, the protective effect is maintained for at least 30 years.
The two-component contraceptive pill contains synthetic equivalents of the two hormones estrogen and progesterone, which trick the body into reacting as if it were pregnant and preventing conception.
Studies have confirmed that estrogen stimulates the development of certain types of cancer, so there have been concerns that oral contraception may increase the likelihood of cancer in the long run. However, a Scottish study found that while women taking the pill increased their risk of developing breast cancer by four percent, the risk subsided within five years of stopping this type of contraception. ‘Thanks to this study, millions of women using oral contraceptives can feel safe knowing that the pill does not increase the risk of cancer and can even lower the risk of several types of cancer,’ said Professor Helen Stokes-Lampard, president of the Royal College of Family Physicians. – Of course, we do not urge women to treat the pill as a cancer prevention measure, because we know that in some cases oral contraception can have an adverse effect on health – she emphasizes.
– The decision to prescribe oral contraception should be made after an individual consultation with the patient. This study brought important information that we will use when talking to patients about the selection of the optimal method of contraception – explains Prof. Stokes-Lampard adds.
It is estimated that about three million British women use oral contraception. Health organizations emphasize that the Scottish study has provided further evidence that the pill may only have minor side effects in the long run. “This large study brings further evidence that oral contraception has an impact on cancer incidence,” said Emma Shields of Cancer Research UK.
– Previous studies have shown that the pill reduces the risk of ovarian and endometrial cancer but increases the risk of cancer of the ovary and cervix. However, we also know that when you stop taking the pill, the increased risk of pediatric and cervical cancer decreases, and the reduced risk of ovarian and endometrial cancer continues for many years to come. Patients who are considering starting or stopping the pill should talk to their doctor about this, she adds.
The results of the study are published in the American Journal of Obstetrics and Gynaecology.