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Updated: Aug 15, 2026
Preterm EEG: A Multimodal Neurophysiological Protocol
Published on: February 18, 2012
Differential effects of breast- and formula-feeding on preterm infants' sleep-wake patterns
1Department of Family and Child Nursing, University of Washington, Seattle 98195-7262, USA. kthomas@u.washington.edu
Insights
Breastfed preterm infants cry more than formula-fed infants. This difference in crying duration impacts infant sleep-wake patterns and has implications for lactation support and research design.
Area of Science:
- Neonatal care
- Infant development
- Sleep science
Background:
- Sleep-wake patterns are crucial for infant development.
- Preterm infants often exhibit altered biorhythms.
- Feeding methods may influence infant behavior and sleep.
Purpose of the Study:
- To compare the sleep-wake patterns of breastfed versus formula-fed preterm infants.
- To investigate the impact of feeding modality on infant crying and sleep behavior.
Main Methods:
- An exploratory study involving 37 preterm infants (12 breastfed, 25 formula-fed) post-NICU discharge.
- Parents recorded infant sleep, awake, and cry states at 30-minute intervals over 24 hours.
- Data included health records and parental reports, with analysis of diurnal and 24-hour patterns.
Main Results:
- Breastfed preterm infants showed significantly more crying (Day and 24-hour) compared to formula-fed infants.
- Breastfed infants cried approximately one hour longer per day.
- A diurnal pattern was observed across crying, awake, and sleep states in all infants.
Conclusions:
- Preterm infants who are breastfed tend to cry more than those who are formula-fed.
- Understanding these differences is vital for effective lactation support strategies.
- Feeding method influences infant sleep-wake cycles, informing future research methodologies.
Objective:
To compare sleep-wake patterns of breastfed and formula-fed preterm infants.
Design:
Data were taken from an exploratory study of infant biorhythm maturation. Parents completed a 24-hour diary of infant Sleep, Awake, and Cry states and feedings, recorded at 30-minute intervals. Infant health data were collected from medical records and parents' reports.
Setting:
Infants were studied in the home after discharge from a neonatal intensive-care unit.
Participants:
The convenience sample included 12 breastfed and 25 formula-fed preterm infants (gestational age, 26-33 weeks; corrected postnatal age, 4-6 weeks). Groups were comparable in terms of gestational age, postnatal age, Apgar scores, maternal age, and home environment.
Main Outcome Measure:
The 24-hour recording period was divided into day (0600-1800) and night (1800-0600). Study variables were Day, Night, and 24-hour Sleep, Awake, and Cry.
Results:
Breastfed preterm infants exhibited more Day Cry and 24-hour Cry than did formula-fed infants. Infants demonstrated a diurnal pattern in Cry, Awake, and Sleep. Breastfed preterm infants cried approximately 1 hour per day more than formula-fed infants.
Conclusion:
Preterm breastfed infants experienced more cry than did formula-fed infants. The relationship between feeding method and sleep-wake pattern has implications for supporting lactation as well as for research design.
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