The idea that abnormalities in the infant may be produced by impressions on the pregnant woman's imagination dates back to the earliest days of medicine. Even Dr. Thomas Morgan Rotch, Professor of Pediatrics at the Harvard Medical School, seemed unwilling to give up this hypothesis as late as 1903, as seems apparent in the following quotation from his famous textbook of pediatrics:
A few words should be said concerning the subject of maternal impressions. For many years there has been accumulating a considerable amount of evidence showing that a violent mental impression made upon a woman who is at the time carrying a child may be followed by a physical or mental defect in the child which bears a striking relation in character to the impression made upon the mother. Thus, Sir Walter Scott narrates that King James the First could not endure the sight of a drawn sword. This feeling had been attributed by those who believe in maternal impressions to the terror which his mother experienced at witnessing the murder of Rizzio. Still more numerous are the facts adduced to prove that bodily defects, such as harelip, club-foot, and hairy mole, may be caused by strong impressions of pain or terror experienced by the mother at the time when the foetus is in a certain stage of intra-uterine development. Interesting as these instances are, it is the general belief that nothing more has been proved than that they depend on a coincidence.
The final decision on this obscure subject must rest on future investigation, and until something more definite is known we should guard a woman during her pregnancy from all unpleasant impressions with far more care than we do at present.1