Abstract
This month’s issue of Breastfeeding Medicine highlights a most interesting study by Bembich and colleagues that investigated what goes on between a mother and her infant during the act of breastfeeding. The bottom line was that during breastfeeding, there are simultaneous cerebral cortical activations of both mother and infant.
Bembich et al. studied 20 mothers and their term newborns during a breastfeeding episode and measured the degree of simultaneous cerebral cortical activation utilizing multichannel near-infrared spectroscopy (NIRS) methodology. As is known, NIRS detects changes in hemoglobin concentration and thus the degree of oxygenation as a measure of cerebral metabolic activity.
Analyzing the results from multiple cortical regions, they detected increased activity simultaneously in both the mothers’ and the newborns’ frontal, motor, and primary somatosensory cortical areas during the first 5 minutes of breastfeeding. Mothers showed an activation of the central motor/primary somatosensory cortex, above the sagittal fissure, while in newborns the bilateral frontal cortex was activated. Further analysis revealed two cyclical synchronizations between mothers’ and infants’ activated cortical regions, truly an interactive phenomenon.
In the opinion of the authors, such synchronization “may reflect a common sharing and exchange of experiences in the mother infant dyad that is associated with reciprocal dynamic motor adjustments and co-regulation, somatic and olfactory sensations, hormonal synchronicity and attachment related emotions during the act breastfeeding.”
In simple terms, breastfeeding acts as an enhancer of the mother–infant dyadic attachment process.
While I rarely quote data obtained from nonhuman studies and animal models, a most recent article from Li and colleagues enhanced our understanding of the critical importance of the act of actual physical contact of the newborn preweaning animal with the mother during the attachment process. 1
Li studied the neural basis of the infant–mother bond in mice during the pups’ separation and reunion with their mothers. Somatostatin-expressing neurons in the zona incerta area of the brain increased their activity upon a pup’s reunion and physical contact with its own mother. Modulating the activity of this neuronal population affected stress and learning behavior in pups, suggesting that these neurons are critical for processing social sensory information during infancy.
These studies provide more support for the concept, mechanisms, and the underlying neurological basis of infant development as proposed by Feldman.2,3 In particular, Feldman has emphasized the critical role of an interactive synchronous process that is predicated on direct contact between the mother and the infant, a contact that is facilitated by breastfeeding, which by definition is an interactive process—in particular, the role of breast sucking while breastfeeding and the stimulation of oxytocin production in the mother and the effect of the oxytocin, in turn, in enhancing the developing maternal attachment.
It is inevitable that such data lead one to the conclusion that there is a distinct and unique advantage to the act of breastfeeding per se, as opposed to what is gained by simply feeding breast milk by bottle to the infant. It is clear that the advantage relates primarily to the direct neurobehavioral consequences of the intimate contact of mother and infant. Surely, this advantage relates not to the major critical differences in nutritional, anti-infectious, or anti-inflammatory components of pumped milk versus nursed milk. Again to make it clear: feeding pumped milk by bottle, especially if the feedings are not by the biological mother, is not the same and may not have the same infant neurobehavioral consequences.
What are the clinical implications of the above-noted studies?
Given the reality of mothers feeding pumped milk more routinely, especially when they return to work, or the routine requesting of the mothers’ partners to bottle-feed their infant pumped milk during the night, this is not a theoretical question. 4 I would suggest that working mothers breastfeed at every opportunity, including the night feedings, so as not to “lose” that unique and critical interactive opportunity to enhance infant attachment and maximize neurobehavioral and social development.