A new study finds moms who spent more months breastfeeding are more responsive to their child's needs.

A mother breastfeeding her child, circa 1600. (Photo: Hulton Archive/Getty Images)

Much research suggests sensitive parenting offers physical and emotional health benefits for the child, which can persist into young adulthood. But the ability to stay focused and responsive to a child's needs doesn't necessarily come naturally, and some new mothers fear they may not provide needed nurturing.

Well, new research suggests a simple way to jump-start maternal sensitivity: breastfeeding.

A study published in the journal Developmental Psychology finds mothers who breastfed for longer periods of time are more responsive to their kids' needs a full decade into their young lives.

"Breastfeeding may set in motion a cascade of positive consequences for maternal sensitivity beyond the infant/toddler period," writes a research team led by psychologist Jennifer Weaver of Boise State University.

Weaver and her colleagues analyzed data on 1,272 families who took part in the National Institute of Child Health and Human Development's Study of Early Child Care and Youth Development. They were recruited in 1991, shortly after their child's birth, at 10 hospitals scattered around the United States.

Mothers reported whether they breastfed the child, and if so for how long. Fifty percent did so for six months, but less than 10 percent did for a full year. Over 28 percent did not breastfeed at all.

During the first decade or so of the child's life, researchers visited each household eight times to observe their interactions with their parents. For example, at age six months, they videotaped the mother and baby playing with a set of toys. At four and a half, they watched as "mothers and children completed a problem-solving task by playing with an Etch-a-Sketch."

For assessments at six and 36 months, researchers evaluated the parents' "sensitivity to the child's non-distress signals, positive regard, and intrusiveness" (or lack thereof). Later on, they rated parents' "supportive presence, respect for autonomy," and the extent to which they projected hostility toward the child.

The researchers found that breastfeeding has "positive consequences for material sensitivity" that extend far beyond infancy. Specifically, "mothers who persisted in breastfeeding for a longer duration increased their maternal sensitivity over time," even after taking account of a variety of factors including education and ethnicity.

The effect was relatively small; as the researchers note, the mother-child relationship is complex, and can be influenced by many factors. Nevertheless, breastfeeding seems to be one of them. (Not surprisingly, this effect is limited to mothers; the researchers found no connection to fathers' sensitivity.)

"Breastfeeding has been linked to both activation of brain regions associated with caregiving, and the release of oxytocin," the researchers note. "Additionally, breastfeeding mothers spend more time in close interactive behaviors with their infants."

All in all, "the longer a mother breastfeeds, the longer she is exposed to both biological and situational factors that promote parent-offspring bonding."

Breastfeeding has been linked to a wide range of positive outcomes for both mothers and children, including cognitive benefits and a lower likelihood of obesity. This study provides further evidence that it's a practice employers, and society in general, would be wise to facilitate and encourage.