Oral Contraceptive Myths and Facts Part 4: Side Effects and Long-Term Consequences

Recently, we discussed the endocrine system, a system of glands that produce biochemical substances known as hormones. These include sex hormones, which play an important role, not only in pregnancy, but also in events leading to it. Oral contraceptives, also called birth control pills, consist of hormones that interfere with the signaling between hormones and the ovaries. In this series, we are discussing oral contraceptives from various angles, beginning with some common myths and the facts that resolve those myths. This is part four of the myths and facts component in which we’ll discuss side effects and also questions about cancer.

Myth: You tried oral contraceptives once and didn’t like the side effects, so you’re better off not trying them again.

Fact: Oral Oral contraceptives can produce a range of side effects. These include nausea, vomiting, diarrhea, constipation, gastrointestinal bloating and cramps, changes in appetite (increased or decreased), changes in weight (up or down), breast enlargement, breast tenderness, and swelling of the gums. However, there are many different formulations of oral contraceptives. Different formulations and dosages produced highly varied side effect profiles in different women. You may feel much better on one formulation that you did on another and even the same particular birth control pill may affect you differently at different points in your life.

Myth: Taking oral contraceptives increases your cancer risk.

Fact: Scientific studies have revealed increased risk of developing certain types of cancer among women who take oral contraceptives, but a decreased risk of developing other types of cancers, and overall a lack of association between oral contraceptives and the risk of actually dying from cancer. A range of studies, for instance, has revealed slight to moderate increases in the risk for developing breast cancer. Some of the studies have found such a connection only with the old style “triphasic pill” (in which you switch between three different kinds of pill throughout the month), while others have found it in connection also with some newer pills. These are usually types of breast cancer that are detected early and are fairly treatable. Some studies also have revealed a slight increased risk in developing cervical cancer among women who take oral contraceptives. By way of Pap smear testing, however, cervical cancer, is easily detected at very early, even precancerous, stages, when it is fully curable. Named for George Nicholas Papanicolaou, who pioneered studies of female reproductive physiology and the related cell biology, the Pap has revolutionized screening and prevention of gynecologic cancer. It is very important for you to have your Pap smear and other testing performed on schedule. The procedure has saved the lives of many women.

Meanwhile, oral contraceptives have been found to lower the risk of developing some types of cancers that are not easily detected early and/or tend to be more deadly. This includes ovarian cancer, for which there is not yet even a screening test, so it is often diagnosed a late stage and thus has high mortality. Along with ovarian cancer, oral contraceptive use also is associated with a lower risk of colorectal cancer, which can has a range of outcomes, from detected early and fully cured to deadly, and lower risk of endometrial cancer, which also has varying outcomes, depending on when it is discovered. Scientists also have uncovered evidence suggesting that oral contraceptives may lower your risk of certain female reproductive cancers, particularly when the oral contraceptives are taken after pregnancy.

This ends the myths and facts component of this series, but are still a few things more to discuss about oral contraceptives. Therefore, in the next installment of this series, we’ll transition into the topic of reasons for taking oral contraceptives, other than to prevent pregnancy.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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