Development of infant sleep patterns can play a role in growth, dietary intake, and even socioemotional development.  Although components of breastmilk are known to impact sleep, the existing literature provides an inconsistent association between exclusive breastmilk intake and sleep durations.  Many studies that examined the relationship between breastfeeding and infant sleep were conducted using a single time point, and thus, knowledge about longitudinal sleep trajectories is not possible.  However, work conducted by Wang and colleagues explored this issue and they report those results in the February 2023 issue of The Journal of Nutrition.

Subjects for this study were participants in the Tongji Maternal and Child Health Cohort study.  Feeding practices at 3 months of age determined whether the maternal/child pairs were part of the breastfeeding only group (n=2558 infants), or the group that used partial breastfeeding and/or only formula feeding (n=1948).  Sleep data were obtained at 3, 6, 12, and 24 months of age, and total, night, and day sleep trajectories were estimated.  Sleep trajectories were based on sleep duration at 3 months (long/moderate/short) and the interval from 6-24 months (moderate/short).

Infants not exclusively breastfed had shorter sleep durations at 3, 6, and 12 months, and were more likely to have moderate-short or short-short total sleep trajectories.  Night sleep trajectories in non-exclusive breastfed infants were more likely to be moderate-short and short-moderate.  The authors concluded that these observations indicate exclusive breastfeeding for more than 3 months contributes to better infant sleep trajectories during the first 2 years of life.


Wang W, Huang L, Zhang X, Lin L, Chen X, Zhong C, et al.  Association of breastfeeding practices during the first 3 months with infant sleep trajectories:  A prospective cohort study.  Journal of Nutrition, Volume 153, Issue 2, February 2023, Pages 562-568.

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