A group of scientists studying pregnancy across six different mammals—from humans to marsupials—uncovered how certain cells at the mother-baby boundary have been working together for over 100 million years. By mapping gene activity in these cells, they found that pregnancy isn’t just a battle between mother and fetus, but often a carefully coordinated partnership. These ancient cell interactions, including hormone production and nutrient sharing, evolved to support longer, more complex pregnancies and may help explain why human pregnancy works the way it does today.
