Scientists Challenge a Long-Held Belief About Why Human Childbirth Is So Difficult

A University of Vienna review finds that difficult and dangerous births are common across many mammal species, not just humans.

The evidence shows birth complications, including maternal and fetal mortality, in cows, sheep, seals, deer, whales, elephants, zebras, monkeys, and other mammals.

That weakens the classic idea that humans are uniquely affected by an “obstetrical dilemma” and suggests risky delivery is a broader evolutionary trade-off.

The findings could change how scientists think about reproduction, pelvic constraints, and childbirth across mammals.