“Human evolution has occurred both due to, and in spite of, the placenta. Every pregnancy, unthinkingly, must navigate a careful path through it. Every menstruation is a testament to it. It is partly why menopause exists, to give individuals an escape from the energetic costs associated with its imposition.”
In this adapted excerpt from “Infinite Life: The Story of Eggs, Evolution, and Life on Earth,” (Pegasus Books, 2024) author Jules Howard examines the invasiveness of the placenta — how far it permeates into the wall of the uterus and the maternal tissue — in mammals after the dinosaur-killing asteroid struck.
In many years of writing about the insides and outsides of animals, I confess I have never written of a stranger organ or a weirder evolutionary contract. I find myself quietly saluting the placenta that fought for me in my earliest moments, while simultaneously feeling apologetic to the maternal host in which I grew. This is a world-changing adaptation, in more ways than one.
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