A study published in June of this year looked for evidence of increased hormone levels in women who take birth control pills. It was motivated by evidence that increased hormone levels are linked with breast cancer. The study examined variation in hormone levels in women taking seven different oral contraceptives. Four of the seven were found to quadruple progestin (synthetic version of progesterone) levels and one was found to raise ethinyl estradiol exposure by 40% (compared to naturally produced estradiol ).
Despite the results, the author of this study, Beverly Strassmann, insists that oral birth control is still very important for women's health and that it "has greatly improved women's lives". She states that the takeaway from these findings is that birth control pills should be redesigned to prevent them from increasing hormone levels and, therefore, breast cancer. "Not enough has changed over the generations of these drugs, and given how many people take hormonal birth control worldwide—millions—the pharmaceutical industry shouldn't rest on its laurels."1
- 1. Jennie L. Lovett, Margo A. Chima, Juliana K. Wexler, Kendall J. Arslanian, Andrea B. Friedman, Chantal B. Yousif, Beverly I. Strassmann; Oral contraceptives cause evolutionarily novel increases in hormone exposure: A risk factor for breast cancer. Evol Med Public Health 2017; 2017 (1): 97-108. doi: 10.1093/emph/eox009 https://academic.oup.com/emph/article/doi/10.1093/emph/eox009/3861339/Oral-contraceptives-cause-evolutionarily-novel