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In a nutshell
- Children breastfed for at least 6 months showed 27% lower odds of developmental delays when exclusively breastfed, and 14% lower odds with mixed feeding.
- Benefits were most significant for language and social development, with premature babies showing even greater improvements than full-term infants.
- Maintaining some breastfeeding for longer appears more important than avoiding formula completely, offering reassurance to parents who need to supplement.
KFAR MALAL, Israel — Children who are breastfed for longer periods of time during infancy experience fewer developmental delays and a reduced risk of neurodevelopmental conditions, including disorders like autism and ADHD, acording to new research. The study led by scientists at the KI Research Institute in Israel confirms what many parents might hope to hear: breastfeeding babies for at least six months appears to boost their developmental outcomes.
While health organizations have recommended breastfeeding for the first six months of life for years, this study offers particularly strong evidence by addressing problems that weakened earlier research on the topic.
Published in JAMA Network Open, the study involved health data from 570,532 Israeli children, including nearly 38,000 sibling pairs. It ranks among the largest investigations into breastfeeding and development ever conducted.
Led Dr. Inbal Goldshtein and Dr. Yair Sadaka, the research team used an innovative approach to ensure their findings were reliable. The study uniquely combined routine developmental checkup records from Israel’s maternal-child health clinics with national insurance disability data, allowing researchers to track both developmental milestone achievement and diagnosed conditions.
They compared siblings within the same families who had different breastfeeding experiences but shared genes and home environment. This clever design controlled for family factors like parental intelligence and involvement that often confuse results in other studies.
Children exclusively breastfed for at least six months had 27% lower odds of developmental delays compared to those breastfed for shorter periods. Even children who received both breast milk and formula for six months or more showed a 14% reduction. When examining siblings with different breastfeeding histories, those who breastfed longer had 9% lower odds of milestone delays and 27% lower odds of neurodevelopmental conditions compared to siblings who breastfed for shorter periods or not at all.
The benefits remained clear even after accounting for numerous factors, including pregnancy duration, birth weight, maternal education, family income, and postpartum depression.
The advantages appeared most notable in language and social development—crucial areas for school success and forming friendships. Motor skills improved too, though less dramatically. Premature babies, who typically face higher developmental risks, seemed to benefit even more from extended breastfeeding than full-term infants.
For parents struggling with breastfeeding choices, there’s reassuring news. When researchers specifically examined siblings who both breastfed for at least six months—one exclusively on breast milk and one receiving some formula—exclusive breastfeeding didn’t show a meaningful additional advantage. This indicates that maintaining some breastfeeding for longer might matter more than avoiding formula completely.
The study’s authors believe that their findings should inform public health policies and support systems rather than pressure individual families. Their goal remains helping children reach their potential, not creating guilt among parents facing breastfeeding challenges.
Researchers emphasize that while breastfeeding is linked to better development, it’s just one of many factors that shape a child’s growth. They noted that identifying changeable factors like nutrition is essential to helping each child reach their potential.
Despite expert recommendations, actual breastfeeding rates often fall below targets. Many mothers struggle to balance breastfeeding with work demands, inadequate parental leave, and aggressive formula marketing.
Formula companies spend around $55 billion yearly promoting their products, sometimes undermining women’s confidence in their ability to breastfeed. The authors advocate for stronger supportive policies, including better parental leave and limits on formula marketing practices.
The biological mechanism for these benefits may relate to breast milk’s effects on brain development. Earlier research has shown differences in brain structure between breastfed and formula-fed babies. Some scientists believe these benefits might work through effects on the infant’s gut microbiome, which connects to brain development through what’s known as the gut-brain axis.
As the researchers conclude, these results may help guide not only parents but also public health initiatives aimed at giving children the best developmental start possible. When every advantage counts for our children, supporting breastfeeding appears to be a worthwhile investment.
Struggling with Breastfeeding? Here’s What You Can Do
Breastfeeding can be challenging, and many mothers face difficulties. If you’re struggling:
- Reach Out for Support: Talk to a lactation consultant, healthcare provider, or breastfeeding support group.
- Take Care of Yourself: Stay hydrated, eat well, and rest when possible to maintain your milk supply and health.
- Consider Combination Feeding: Using formula alongside breastfeeding can relieve pressure while still providing breast milk benefits. Be sure to talk to to your pediatrician when making any changes to your baby’s diet.
- Skin-to-Skin Contact: Even if breastfeeding isn’t fully successful, skin-to-skin bonding benefits you and your baby.
- Evaluate Your Technique: Small adjustments in positioning or latch can make a big difference.
- Be Patient and Kind to Yourself: Every effort counts, and your well-being is vital for your baby.
Remember, successful parenting isn’t defined by breastfeeding alone. Seeking support is a strength, not a weakness.
Paper Summary
Methodology
The researchers used three different approaches to ensure their findings were solid. First, they applied statistical techniques to estimate the relationship between breastfeeding and development while accounting for many potentially confounding factors simultaneously. They used methods that could capture complex relationships between variables like pregnancy length, family income, and breastfeeding duration. Second, they created matched pairs of children with similar characteristics except for their breastfeeding experience. Third, and perhaps most cleverly, they compared siblings with different breastfeeding experiences but who shared the same family background. This sibling comparison helped control for unmeasured factors like parental attention and genetic influences that might otherwise affect results. The study combined data from routine developmental checkups with national insurance records, giving researchers insight into both developmental milestone achievement and diagnosed conditions.
Results
The findings showed clear benefits from longer breastfeeding. Children exclusively breastfed for at least six months had 27% lower odds of developmental delays compared to those breastfed less than six months. Those who received both breast milk and formula for at least six months showed a 14% reduction. The benefits appeared strongest for language and social development, though motor skills also improved. For diagnosed conditions including autism, ADHD, and severe behavioral disorders, breastfeeding for at least six months was associated with 28% lower odds. The sibling comparison results were particularly compelling—even within the same family, the child who breastfed longer had 9% lower odds of milestone delays and 27% lower odds of neurodevelopmental conditions. The researchers also found that more months of breastfeeding correlated with better outcomes, with benefits becoming evident early on and continuing to accumulate before leveling off around 10-12 months.
Limitations
Despite its strengths, this study has important limitations. While the researchers worked hard to control for confounding factors, they couldn’t rule out that some medical conditions weren’t fully captured in the data. The study focused on babies born after at least 35 weeks of pregnancy without serious illness, so the findings might not apply to very premature or medically complex infants. Additionally, the researchers couldn’t separate the benefits of breast milk itself from the close physical contact that typically accompanies breastfeeding. The sibling analysis, while powerful for controlling family-level influences, wasn’t possible among premature children because so few families had multiple premature children with different feeding patterns. Finally, like all observational studies, this research established associations but cannot prove causation—only a randomized trial could do that, and randomly assigning infant feeding methods would raise ethical concerns.
Discussion and Takeaways
Several important points emerged from the researchers’ discussion. First, the link between breastfeeding and developmental outcomes remained consistent across different analytical approaches, strengthening confidence in the findings. Second, while the relative benefits were similar for premature and full-term babies, the absolute improvement appeared greater for premature children because of their higher baseline risk of developmental issues. This suggests supporting breastfeeding might be particularly valuable for vulnerable infants. Third, the benefits increased with more months of breastfeeding but seemed to plateau after about a year. Interestingly, when comparing siblings who both breastfed for at least six months—one exclusively and one with some formula—exclusive breastfeeding showed no significant additional advantage. This may reassure parents who need to supplement with formula but can continue some breastfeeding. The researchers framed their work as evaluating a changeable factor for optimizing development, emphasizing their aim was not to judge neurodiversity but to help each child maximize their abilities.
Funding and Disclosures
This research received funding from Horizon Europe (grant agreement 101057385) and UK Research and Innovation (grant 10039383, R2D2-MH). Dr. Zimmerman disclosed being the director of the Maternal Child and Adolescent Department of the Public Health Directorate of Israel’s Ministry of Health, which operates the health centers providing the medical record data. No other conflicts of interest were reported. The funders played no role in designing the study, collecting or analyzing data, preparing the manuscript, or deciding to publish.
Publication Information
This study, “Breastfeeding Duration and Child Development,” appeared in JAMA Network Open on March 24, 2025 (Volume 8, Issue 3, article e251540). The research team included Dr. Inbal Goldshtein and Dr. Yair Sadaka, along with colleagues from various institutions including KI Research Institute in Israel, the Neuro-Developmental Research Center in Israel, the National Insurance Institute of Israel, Institut Pasteur in France, and the University of Cambridge in the United Kingdom. The study followed standard reporting guidelines for observational research and received approval from the Soroka Medical Center ethics board with an informed consent waiver since all data was anonymized.
