Antenatal olfactory learning influences infant feeding.

The aim is to know whether antenatal olfactory learning have a greater effect than postnatal olfactory learning on infant feeding even in the absence of triggering signals. We evaluated the sucking behavior of infants completely separated from their mothers for 10-14 days since birth. The 12 infants admitted to Chiba Children's Hospital were studied at 10-14 days of age. Oral feeding was initiated at 4-7 days of age. The sucking and expression pressures, frequency, and sucking efficiency were measured during bottle-feeding with exposure to odors of mother's milk, formula, and water. The mother's milk odor elicited more frequent sucking with higher expression pressure than did formula or water. In conclusion, the odor preferences acquired independently from postnatal experience may have a greater effect than postnatal olfactory learning on sucking activity.