Understanding Miscarriage through Evolutionary Biology: Conversation with Dr. Jan Brosens, Part I

Since women have been having babies they've experienced miscarriages. For nearly as long, we have not had a useful way to address miscarriage. Often doctors shrug at your first miscarriage and say it's a normal part of pregnancy. And if it arises because of aneuploidy, the fertilized egg has the wrong number of chromosomes, at this point there is not much we can do about that. But there are many routes to miscarriage. Today's guest is working to better understand other mechanisms at play in miscarriage. One of his guiding principles is to recognize that pregnancy in humans works according to its own rules. Adaptations that the human body has made that allow for a 9 month relationship between a fetus developing entirely inside it's mother's body don't exist in any other part of the body. Take, for example, the case of the placenta. there are a class of cells in the placenta that rapidly divide, invade uterine tissue and evade the immune system; this is critical to the development of a maternal fetal interface, but a similar pattern of cell growth outside of the context of pregnancy is often called cancer.  Understanding how human reproduction has evolved to address the challenge of a long pregnancy inside a woman's body has guided today's guest in his work to identify the specific factors that contribute to or prevent implantation, pregnancy and miscarriage.Here's a link to the 2025 paper in Science Advances with more details: https://www.science.org/doi/10.1126/sciadv.adv1988