The broader message is unsettling and clarifying at once. Human childbirth is risky, but it may not be uniquely risky. Instead, the research suggests that difficult birth is part of a wider mammalian ...

For centuries, childbirth’s pain was explained as punishment; more recently, as the evolutionary price of walking upright and bearing large-brained babies. But if difficult birth occurs across ...

Human babies have large heads, and the shape of the human birth canal remains distinctive. The fetus usually has to rotate through the canal in a way that has not been documented in other mammals.