June 6, 2017
In the evolutionary past, women spent most of their reproductive lives either pregnant or in lactational amenorrhea, and rarely menstruated. The current pattern of frequent menses, and the associated increase in endogenous hormonal exposure, has been implicated in the current breast cancer epidemic. It is not known, however, whether oral contraceptives further increase, or actually decrease, hormonal exposure over one menstrual cycle. In this co-authored paper, “Oral contraceptives cause evolutionarily novel increases in hormone exposure: a risk factor for breast cancer”, Kendall and her collaborators examine variation in hormonal exposure across seven oral contraceptive formulations, producing the first quantitative comparison of exogenous versus endogenous hormone exposure.