Is Female Health Cyclical? Evolutionary Perspectives on Menstruation

TL;DR

This paper explores the evolutionary reasons behind menstruation, proposing that female immunity varies cyclically in menstruating species and examining its implications for health, behavior, and host-pathogen interactions.

Contribution

It provides a theoretical framework linking menstruation to cyclical immunity and reviews evidence for immune modulation in humans, highlighting its importance for health and evolutionary dynamics.

Findings

Evidence supports cyclical immune variation in menstruating species

Menstrual modulation of immunity influences health and disease susceptibility

Implications for female behavior and host-pathogen interactions

Abstract

Why do some females menstruate at all? Answering this question has implications for understanding the tight links between reproductive function and organismal immunity. Here we build on the growing evidence that menstruation is the by-product of a "choosy" uterus to (i) make the theoretical case for the idea that female immunity is cyclical in menstruating species, (ii) evaluate the evidence for the menstrual modulation of immunity and health in humans and (iii) speculate on the implications of cyclical female health for female behaviour, male immunity and host-pathogen interactions. We argue that an understanding of females' evolved reproductive system is foundational for both tackling the future challenges of the global women's health agenda and predicting eco-evolutionary dynamics in cyclically reproducing species.