Do Human Fetuses Form Long‐Lasting Chemosensory Memories? Longitudinal Follow‐Up From Fetus to Young Child of Facial Responses to Flavor/Odor Stimuli

Prenatal flavor exposure is known to provide the foundation for later flavor or odor preferences in humans, yet the persistence of fetal flavor/odor memories into early childhood remains unclear. In previous studies, fetuses at 32‐ and 36 weeks gestation were shown to display discriminative facial reactions following a single‐dose flavor stimulation (bitter kale vs. non‐bitter carrot), and repeated exposure to these flavors from 36 weeks until birth was associated with responses to flavor‐specific odors in the first postnatal month. The current longitudinal follow‐up tested whether the prenatal exposure to two specific flavors results in flavor‐specific odor reactions at 3 years of age. Children (n = 12) who had participated in the fetal and neonatal phases of the study were tested at 3 years of age using controlled olfactory presentations of the same flavors. Results showed that the 3‐year‐olds exhibited a significantly reduced rate of negative facial expressions in response to the odor they had been repeatedly exposed to in utero (p < 0.001), indicating continuity from prenatal sensory experience to early childhood behavioral responses. Thus, flavor exposure in late gestation can result in long‐lasting flavor/odor memory, confirming that the prenatal chemosensory environment can shape behavioral tendencies years after birth.