Breastfeeding May Help Infants Achieve Adequate Sleep - Summary - MDSpire

Breastfeeding May Help Infants Achieve Adequate Sleep

A nationwide birth cohort found lower odds of short sleep at 1 year among infants breastfed during the first 6 months of life, regardless of formula supplementation.

  • By

  • Andrea Surnit

  • July 15, 2026

  • 3 min

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Objective:

To investigate the association between breastfeeding during the first 6 months of life and sleep duration at 1 year in infants.

Approach:
  • Study Design: Analysis of data from the Japan Environment and Children's Study, a nationwide birth cohort study.
  • Participants: 82,918 mother-infant pairs with complete data on infant feeding and sleep duration.
  • Feeding Categories: Infants categorized as exclusively formula-fed, breastfed for less than 6 months, breastfed for 6 months with formula supplementation, or exclusively breastfed for 6 months.
  • Outcome Measurement: Primary outcome was short sleep duration at 1 year, defined as fewer than 11 hours of sleep per day.
Key Findings:
  • 12% of exclusively formula-fed infants experienced short sleep duration compared to 10% of exclusively breastfed infants.
  • Breastfeeding for less than 6 months was associated with 16% lower odds of short sleep.
  • Breastfeeding for 6 months with formula supplementation was associated with 21% lower odds.
  • Exclusive breastfeeding for 6 months was associated with 23% lower odds of short sleep.
Interpretation:

The study found an association between breastfeeding during the first 6 months of life and lower odds of short sleep duration at 1 year, but it could not establish causality.

Limitations:
  • Feeding practices and sleep duration were based on parental questionnaires, which may introduce recall bias.
  • The observational nature of the study limits causal inference.
  • The overall effect size was modest, with a maximum absolute difference of about 3 percentage points.
  • Residual confounding may remain despite adjustments.
Conclusion:

The study found an association between breastfeeding during the first 6 months of life and a decreased risk of short sleep duration in 1-year-old infants.

Sources:

Original Source(s)

Breastfeeding May Help Infants Achieve Adequate Sleep

  • by Andrea Surnit

  • July 15, 2026

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