The Evolution of the Human Placenta

The development of a fully functional placenta was crucial to the evolution of human beings. It is the active interface of the most biologically intimate connection between two living organisms: a mother and her fetus. The Evolution of the Human Placenta discusses everything from the organ’s methods of protecting the fetus from the mother’s own immune system to placental diseases. Starting with some of the earliest events that have constrained or influenced the path of placental evolution in mammals and progressing to the specifics of the human placenta, this book examines modern gestation within an evolutionary framework. Human beings, in terms of evolution, are a successful, rapidly multiplying species. Our reproductive physiology would appear to be functioning quite well. However, human gestation is fraught with many poor outcomes for both the mother and fetus that appear to be—if not unique—far more common in humans than in other mammals. High rates of early pregnancy loss, nausea and vomiting during pregnancy, preeclampsia and related maternal hypertension, and preterm birth are rare or absent in other mammals yet quite typical in humans. Michael L. Power and Jay Schulkin explore more than 100 million years of evolution that led to the human placenta, and in so doing, they help unravel the mysteries of life's earliest moments.