In the literature: dispelling hallucinations about birthweight: how hard is it?

Birthweight is an important determinant of perinatal outcome and future health well into adulthood. Before weighing newborn infants became enshrined in practice, birthweights tended to be based on an educated guess or, as alleged by Roederer in 1753, on hallucination. Two centuries later, they led to a Babylonic confusion between weight and maturity at birth. Even nowadays, hallucinations about birthweight and its effect on infant health have not entirely disappeared. New hallucinations still emerge and remain as difficult to dispel as they once were.