Neonatal cortical perceptions of maternal breast odours: A fNIRS study

The aim was to determine whether preterm and full-term newborn infants could process maternal breast odour at a cortical level.

Newborn infants were exposed to cloths containing their own mother's breast odour and freshly laundered control cloths for 10 seconds, while functional near-infrared spectroscopy measured cortical activation in their olfactory processing areas. We studied 45 newborn infants born at 28-41 weeks of gestation and divided them into three groups: full-term (37-41 weeks), late preterm (33-36 weeks) and very preterm (28-32 weeks). Cortical activation was defined as a regional increase of oxyhaemoglobin following maternal breast odour stimuli.

Full-term infants demonstrated bilateral activation of their olfactory cortices following exposure to maternal breast odour. Late preterm infants and very preterm boys exhibited unilateral cortical activation, unlike very preterm girls.

Infants born from 32 weeks, and possibly earlier, could process low concentration maternal odours at a cortical level, which suggests they were more aware of their environment. These findings could make a significant contribution to improving the sensory environment of preterm infants and improve bonding.