Preventing Pregnancy Prevents Cancer
Written by Laurel Geraci
Edited by Chloe Chou
March 21, 2022
Edited by Chloe Chou
March 21, 2022
It’s no surprise that more than 80% of women in the western world have used oral contraceptives before (Brynhildsen, 2014)–but did you know there could be even more benefits than just preventing pregnancy? According to new studies by scientists at Uppsala University, long term users of oral contraceptives have significantly lower risks of ovarian and endometrial cancer than women who have never used them! In a study of over 250,000 British women, with the youngest being 50 and the oldest being 82 in 2021, about 73% have been users of oral contraceptives for an average of 10.7 years (Karlsson et al., 2021). The study also found that there was a strong negative association between contraceptive use time and developing ovarian or endometrial cancer. Studies are also being conducted about the link between contraceptive use and decreased breast cancer risk, though no conclusions can be drawn yet.
How long can these benefits last for? In this study, scientists found women could reap the benefits of lower ovarian and endometrial cancer risk for up to 35 years after they stop using oral contraceptives! Additionally, their analysis showed the longer the usage of oral contraceptives, the lower the cancer risk was! For endometrial cancer, users for less than 2 years had an odds ratio of about 0.8, meaning these users had 80% of the odds of developing endometrial cancer compared to the non-users. However, users of at least 20 years had a significantly lower odds ratio of 0.4! Similar but slightly weaker patterns were observed for ovarian cancer; less than two year users had an odds ratio of about 0.8 for ovarian cancer, but users for longer than 20 years had an odds ratio of 0.6 (Karlsson et al., 2021).
Considering historically low levels of research done on women’s bodies, this news is refreshing and important to many female patients. It’s likely that these contraceptives have the effects they do because they inhibit ovulation, a process that involves both the ovaries and the endometrium. Without the normal increase in hormones involved in ovulation, the likelihood of cancer development triggered by hormone increases goes down significantly. This protective effect is not, however, reflected in breast cancer; in oral contraceptives users, there was found to be a shorter dormancy period for breast cancer. Although there is not a larger risk of breast cancer, breast cancer cells do grow more quickly in the presence of estrogen and progesterone (Lunachi et al., 2013).
Despite the current unknowns, there are high hopes for women’s reproductive health everywhere. Especially with nonprofit organizations such as Planned Parenthood, it’s becoming increasingly easier to get the health treatment women desperately need. Though it is not perfect and there are undoubtedly unpleasant side effects for many women, oral contraceptives still provide promise for preventative cancer treatment.
References
Brynhildsen J. (2014). Combined hormonal contraceptives: prescribing patterns, compliance, and benefits versus risks. Therapeutic advances in drug safety, 5(5), 201–213. https://doi.org/10.1177/2042098614548857
Karlsson, T., Johansson, T., Höglund, J., Ek, W. E., & Johansson, Å. (2021). Time-Dependent Effects of Oral Contraceptive Use on Breast, Ovarian, and Endometrial Cancers. Cancer research, 81(4), 1153–1162. https://doi.org/10.1158/0008-5472.CAN- 20-2476
Lumachi, F., et al. (2013). Treatment of estrogen receptor-positive breast cancer. Current medicinal chemistry, 20(5), 596-604. https://doi.org/10.2174/092986713804999303