A Theoretical Proposal for Late Luteal Phase Behavioural Changes in an Evolutionary Context

Abstract

Late luteal phase behavioural changes (LLBC) have been reported for humans and some other primates, and encompass a wide spectrum of behaviours. Several studies have estimated that a majority of women manifest some LLBC. At a more extreme end of the spectrum, in a small minority of women, LLBC have been classified as major emotional disturbances or medical conditions (although not without controversy), for example, as part of premenstrual dysphoric disorder. In this report, an attempt is made to place LLBC in an evolutionary context; some of these behaviours, in particular at a less extreme end of the spectrum, may have co-evolved with reproductive physiology. Evolutionary perspectives upon human reproductive behaviour are often complex (and controversial) issues; in this context, specific and more isolated mechanisms for possible evolutionary stability of some LLBC-e.g., related to male-female behavioural interactions-are suggested for further discussion. Overall, it is proposed that qualitative and quantitative changes in hormones and hormonal activities during the menstrual cycle evolved to optimize reproductive success through neurophysiological responses that include behavioural components, perhaps some LLBC.