To Bond or Not to Bond: Breastfeeding Research

indicates that mothers who breastfeed their children are more likely than mothers who formula-feed to bond with their infants in their first few months, according to a study publishing in the May issue of the Journal of Child Psychology and Psychiatry.

Researchers also reported that mothers who breastfed their infants exhibited stronger brain responses to the sound of their baby crying.

Researchers from the Child Study Center at Yale University separated the mothers participating in the study into two groups: breastfeeders and formula feeders. They then performed functional MRIs (fMRI) on the mothers roughly one month following the birth of their children.

During the fMRI, the nine breastfeeders and eight formula-feeders were asked to listen to audio of their own baby crying and then listen to audio of an unknown baby crying. The researchers tracked which areas of their brains lit up, and discovered that while all mothers’ brains were more active while listening to the cries of their own child, the changes in the breastfeeders’ relevant brain regions were more drastic.

Researchers matched the women in both groups for age, education, and income levels, as previous studies have shown that formula-feeding moms may fall into a lower socioeconomic bracket. As such, the women participating in the study were all white, middle- to upper-class women with at least a college degree.

Lead research Pilyoung Kim, a developmental psychologist at the National Institutes of Mental Health who worked at Yale when the study was conducted, warned that while the findings indicate a stronger bond between breastfeeders and their children, women who did not breastfeed should not feel that they did the “wrong” thing.

“We want to suggest to people that a number of different factors may be related to breast-feeding mothers' greater sensitivity to infant cries and infant cues, not just because they're breast-feeding but because of hormonal levels or other personal experiences,” said Kim.

For example, said Kim, hormonal levels vary between mothers who breastfeed and those who don't. Oxytocin, the hormone that facilitates emotional bonding between infants and mothers, is higher in breastfeeding moms.

Psychological aspects also are likely factors. “Moms who decide to breast-feed might be reflecting a general tendency of mothers to be more empathetic to their infants or perhaps they were more able to bond easily with their fetus when they were making the decision about wanting to breast-feed,” stated Kim.

As a mother who chose to breastfeed, Kim understands the competitive undertone that accompanies infant feeding choices. “I know how challenging this is,” she said. “We didn't have a particular agenda in our minds when we decided to conduct this research.”