Why do women get PMS? - Chris Williamson
Evolutionary biologist Michael Gillings offers a provocative suggestion: The condition nudged ancestral women to ditch infertile partners.
For most of our evolutionary history, women were pregnant or breastfeeding most of the time, and thus regular menstrual cycles were rare… except among women paired with men who couldn’t get them pregnant.
If premenstrual irritability increased the chances of such pairings dissolving, women could move on to more fertile partners, boosting their odds of passing on their genes.
Supporting evidence for the theory includes the fact that anger during PMS is often directed at one’s partner.
If Gillings is right, then PMS isn’t a biological accident but an evolved mechanism now mismatched with the modern world - a world in which even fertile couples often choose to postpone having children or forgo it altogether. — Steve Stewart-Williams