There is no evolutionary “obstetrical dilemma”
Holly Dunsworth
Abstract
The “obstetrical dilemma” hypothesis (OD) has long been a popular explanation for the evolution of childbirth difficulty and human neonatal helplessness. But since it was conceived, over seventy years of intensive knowledge production has not provided evidence to support the OD. Contrary to explicit and implicit assumptions of the OD, humans are not born early and gestation is not truncated. Women’s hips are not compromised. Bipedalism’s pelvic correlates did not limit pregnancy or fetal growth. And, birthing big babies did not bring about sex differences in the pelvis. Here we journey through current knowledge that fails to support the OD and that illuminates alternative perspectives. Human parturition is difficult and we care intensively for birthers and neonates, but the OD is unnecessary, at best, for explaining the evolution of these phenomena. OD thinking has likely contributed to the rise in unnecessary and unwanted childbirth interventions by the medical community. Given the OD’s continued popularity, it is likely that this non-existent phenomenon will continue to impact human behavior.