(HealthDay News) — Breastfeeding duration is associated with better understanding of language at age 3 years and better verbal and nonverbal intelligence at 7 years, results from a prospective cohort study indicate.

“These findings support national and international recommendations to promote exclusive breastfeeding through age 6 months and continuation of breastfeeding through at least age 1 year,” Mandy B. Belfort, MD, MPH, from Boston Children’s Hospital, and colleagues reported in JAMA Pediatrics.

The researchers examined data from 1,312 mothers and children who participated in Project Viva, a study that enrolled pregnant women from April 1999 through July 2002 and followed them and their children until the children were aged 7 years.

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After adjusting for sociodemographics, maternal intelligence and home environment, the researchers found that longer breastfeeding duration correlated with a higher Peabody Picture Vocabulary Test score at age 3 years — an increase of 0.21 points for every month of breastfeeding.

Longer breastfeeding duration was also associated with higher intelligence on the Kaufman Brief Intelligence Test at age 7 years — an increase of 0.35 per month on the verbal scale and 0.29 points per month on the nonverbal scale. Overall, children who were breastfed scored an average of 3.75 points higher on this test than those who were not.

There was no correlation between breastfeeding duration and Wide Range Assessment of Memory and Learning scores. All of the tests used are based on a 100-point scale.

Breastfeeding has been linked to other health benefits, including reductions in gastroenteritis, otitis and atopic eczema.

In an accompanying editorial, Dimitri Christakis, MD, of the Seattle Children’s Hospital Research Institute, noted that sustaining breastfeeding seems to be a greater problem for U.S. women than initiating the behavior — 70% of women start breastfeeding, but only 35% of women overall and 20% of black women are still breastfeeding after six months.

“[A] large, robust, and sustained effort is needed to provide the infrastructure to support breastfeeding at all levels,”  Christakis wrote.

He proposed several ways to help mothers sustain breastfeeding such as taking legislative action to ensure that postpartum nurse visits and breast pumps be covered by insurance and launching social media campaigns to destigmatize breastfeeding in public.

Study limitations include the observational nature of the study and the potential for unmeasured factors to affect outcomes.


  1. Belfort MB et al. JAMA Pediatrics 2013;():-. doi:10.1001/jamapediatrics.2013.455.