Scientists have long established a link between birth control pills and reduced risk of ovarian cancer. More recently, a 2018 study revealed that the latest versions of oral contraceptives offer even more protection.
According to the authors of the study, the new and improved pills typically have lower doses of estrogen and older progestogens in comparison to previous versions of the pill.
The researchers examined the effect of new versions of birth control pills on the rates of ovarian cancer in young women. “We found a reduced risk of ovarian cancer in current or recent users of hormonal contraceptives than in former users. The reduction in risk became stronger the longer time period hormonal contraceptives were used, and the reduced risk remained several years after stopping,” Lisa Iversen, PhD, the lead author of the study and a research fellow at the University of Aberdeen in Scotland, told Healthline.
Iversen explained further, saying “We knew from previous studies of the association between combined oral contraceptives and ovarian cancer, so our results might have been expected. However, previous studies were based on women who were mostly older than reproductive age, and therefore, former users of oral contraceptives who would have used older products.”
“It was necessary to conduct our study to investigate whether hormonal contraceptive use in women currently of reproductive age would still be associated with a reduced risk of ovarian cancer,” said Iversen.
Do modern birth control pills prevent ovarian cancer?
To test their theory, Iversen and her colleagues analyzed data from approximately 1.9 million women in Denmark between the ages of 15 and 49.
They placed the women into three categories: (1) women who had never used the pill; (2) women who are currently or recently using the pill and had stopped in the last 12 months; and (3) former users who stopped taking the pill over 12 months ago. The combined oral contraceptives accounted for 86 percent of use of hormonal contraceptives. The researchers considered additional factors, inducing family history of ovarian cancer, age, and education.
They found that the risk of developing ovarian cancer was highest among the group of women who had never taken the pill. Meanwhile, the ovarian cancer risk was lower among women who had taken the pill.
Based on the findings, the researchers estimated that hormonal contraceptives helped prevent about 21 percent of ovarian cancers in the women who took the oral contraceptive. However, the researchers did not find substantial evidence of a protective impact against ovarian cancer among women who had taken progestogen-only products. Iversen noted that a small number of women in the study exclusively took such forms of birth control pills, therefore, the data may not be strong enough to give a good indication.
Cancer among women in the United States
The United States is home to 61 million women of reproductive age. More than 15 percent, or approximately 9 million out of 61 million women, use oral contraceptives.
In 2020, the American Cancer Society estimates 21,750 women in the country will receive a diagnosis of ovarian cancer, and 13,940 will die from the disease. Ovarian cancer is one of the top causes of cancer-related deaths among women and it is accountable for more deaths than any other form of gynecologic cancer.
Almost all studies on cancer and birth control pills have been observational. Therefore, they cannot definitively prove whether oral contraceptives can prevent (or even cause) cancer. However, according to the National Cancer Institute, many studies have provided substantial evidence showing that among women who use birth control pills, the risks of developing breast and cervical cancers are higher, whereas the risks of ovarian, endometrial, and colorectal cancer are lower.
Researchers have hypothesized a number of potential reasons as to why the birth control pill helps lower the risk of some malignancies. In the case of ovarian cancer, it is likely because it suppresses ovulation.
“The total number of ovulation cycles that a woman has in her reproductive life is correlated with the risk of ovarian cancer. Anything that decreases the number of ovulations is associated with decreased risk of ovarian cancer. This includes pregnancy, breastfeeding, and use of the oral contraceptive pill. The benefits of oral contraceptive pills fade with time after the woman is no longer using the pill,” Dr. Gary Scott Leiserowitz, chair of the department of obstetrics and gynecology at the University of California at Davis, told Healthline.
Longevity of the pill’s protective benefits
Women who use birth control pills have a 30 to 50 percent reduced risk of developing ovarian cancer compared with women who have never taken the pill. This protection against cancer increases with the amount of time a woman uses birth control pills. Previous studies on older forms of oral contraceptives even suggest that this protective benefit can last for up to 30 years after a woman stops taking the pill.
Iversen’s study did not gauge or assess the duration of the modern pill’s protective effects, as she and her colleagues did not include older women in their study. However, Iversen says the findings should still be valuable to younger women.
“Our findings of a reduced risk of ovarian cancer associated with contemporary combined oral contraceptives are reassuring for women currently of reproductive age,” she said.
Prevention is important due to the lack of reliable screening available
With the exception of cervical cancer, there is no simple or direct way to screen for gynecologic cancers. Most ovarian cancers — the gynecologic cancer with the most number of deaths — are not diagnosed until they are in the later stages, as symptoms such as bloating, vaginal bleeding, discharge, and back pain are easy to mistake for other, less serious conditions.
“There is no good screening test for ovarian cancer, which is the deadliest gynecologic cancer. We need to use whatever tools we have available to prevent it from developing. Oral contraceptive pills are one of these tools,” Dr. Dineo Khabele, director of the division of gynecologic oncology at the University of Kansas Medical Center, told Healthline.
As the saying goes, “prevention is better than cure.” New versions of the birth control pill may provide more protective benefits against ovarian cancer in comparison to older versions. The reduced risk may be stronger the longer a woman uses oral contraceptives, and the protective benefit may last several years after stopping the pill.
A quick reminder: Before taking any new medications, over-the-counter drugs, supplements, or herbs, please consult a physician for a thorough evaluation.