subjects, when discussing them, seemed to avail themselves of specific knowledge of embryology and the physiology of pregnancy that was far superior to their previous education in these areas. They have often accurately described certain characteristics of the heart sounds of the mother and child; the nature of various acoustic phenomena in the peritoneal cavity; specific details of positions, physical features, and behavior of the fetus
Grof argues that LSD subjects access accurate, verifiable intrauterine data exceeding their prior knowledge, treating the fetus as a site of recoverable transpersonal memory.
, Realms of the Human Unconscious: Observations from LSD Research, 1975thesis