Feb 22, 2018

Interview Transcript

Dr. Jones: Many women fear that their birth control pills, which protect them against unwanted pregnancies, will harm them in the long run. Maybe that's a guilt thing, but what if the opposite is true? This is Dr. Kirtly Jones from Obstetrics and Gynecology at University of Utah Health, and this is "Good News" on The Scope.

Announcer: Covering all aspects of women's health, this is the Seven Domains of Women's Health with Dr. Kirtly Jones, on The Scope.

Dr. Jones: Many women make the connection between taking hormones for birth control and female cancers. Breast, ovary, uterus, this is a rational irrational fear, completely understandable. Our female parts are female because of female hormones, so taking female hormones such as the ones in birth control pills might have some effect, right? Well, so many women have taken birth control pills in their lifetime, at least 30% in the United States, and we have the ability to do population studies on a lot of women to see if there is really a risk. And a new study adds to older studies to confirm that women who take pills have a lower risk of uterine and ovarian cancer. A much lower risk, and the risk of breast cancer in pill users is still very small.

This new study showed that the longer women took pills the lower the risk, and the risk reduction was greatest in women who were obese, and smokers, and non-exercisers, and these are women who are usually discouraged from taking birth control pills, and these are women who are usually at higher risk of uterine and ovarian cancer. Almost 40 years ago, the Centers for Disease Control did a study comparing birth control use in women with breast, ovarian, and uterine cancer with women who didn't have these cancers. They found that women who didn't have uterine and ovarian cancer were more likely to have taken birth control pills. From that study it was suggested that taking birth control pills lowered the risk of ovarian and uterine cancer by about half. The study didn't find any increased risk of breast cancer in pill users.

This month, a study was published that followed about 200,000 women from 1995 to 2011. Women at the start of the study reported their diet, their exercise, their weight, tobacco and alcohol use, and many other health and lifestyle factors including past use of birth control pills. None of the women had cancer at the beginning of the study. About half the women had used birth control pills at some time in their lives, half of them. Some just for a short period of time of 1 to 4 years, some for 5 to 9 years, and some for at least 10 years. And that's how they divided it up in this study.

Most of them were menopausal at the beginning of the study, but they reported the use of hormonal birth control when they were younger. The study confirms with other studies that have also shown that the risk of ovarian and uterine cancer in pill users, especially long term users of more than 10 years, is about one third to one half of what the risk is in women who didn't use hormonal birth control. We know that birth control users are less likely to be obese and less likely to be smokers, and obesity and smoking can be risk factors for cancers. But looking at smokers or overweight women who did take the pill, their risk of ovarian or uterine cancer was even lower than overweight women smokers who didn't take the pill. This is important and in addition to our understanding of the decreased risk of uterine and ovarian cancer in pill users.

Importantly, there was no increased risk of breast cancer in pill users, the same finding as in the previous study from the U.S. Centers for Disease Control. But to sum it all up, there may be a very slight increased risk of breast cancer in hormonal birth control users, but it is tiny. Now, the pills that the women used in the study were probably on average a somewhat higher dose of hormones than most of the pills we're marketing today, and we wait to see if lower doses of pills offer the same protection. So the good news is that birth control pills seem to protect women to some degree from ovarian and uterine cancer, and their protection increases with longer use and continues even after women have stopped taking the pills. The protection includes overweight and obese women who are at increased risk of ovary and uterus cancer.

We know that hormonal birth control pills with estrogens do have some risks, particularly the slightly increased absolute risk of blood clots. Overall though, for a medication taken by a large proportion of women around the world, there is mostly good news about the safety and continuing good news about protection against uterine and ovarian cancer. So don't worry when you put that pill in your mouth. It's probably good for you, and thanks for joining us on The Scope.

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