Moderated Mediation of Infant in Utero Cortisol Exposure, Temperament, Breastfeeding and Sleep
Additional Funding Sources
This work was supported by the Idaho State University Departments of Psychology and Physical/Occupational Therapy, College of Arts & Letters, and by a 2018-2019 STEM Undergraduate Research Grant from the Higher Education Research Council.
Abstract
Objective: Infant sleep problems are notable concerns for parents, having lasting effects on health, development, and functioning throughout the lifespan. Although studies support relations between infant sleep and individual risk factors like prenatal cortisol exposure, breastfeeding, and temperament, no known studies have examined interactive relations among these variables and long-term infant sleep outcomes, which was the current study’s aim.
Methods: Expectant mothers (n=78) provided diurnal salivary cortisol samples at 35±2 weeks gestation and returned at 6 and 14 months postpartum to complete questionnaires regarding infant behavior, health, sleep, and diet.
Results: Increased 6-month breastfeeding frequency predicted decreased 14-month sleep quality, while controlling for main/interactive effects of cortisol and temperament. Prenatal cortisol exposure and temperament had no significant main or interactive effects on 14-month sleep quality, though infants with greater 6-month Surgency/Extraversion (r=.367,p=.036) and Orienting/Regulation scores (r=.391,p=.024) had better sleep quality at 14 months.
Discussion/Conclusion: Findings replicate literature highlighting associations between greater breastfeeding frequency and poorer infant sleep quality, likely due to greater incidence of night waking and sleep location variability. Given recent literature suggesting the normalization of sleep patterns by 6 months postpartum regardless of breastfeeding status, follow-up studies should investigate factors that may account for differences in sleep trajectories.
Moderated Mediation of Infant in Utero Cortisol Exposure, Temperament, Breastfeeding and Sleep
Objective: Infant sleep problems are notable concerns for parents, having lasting effects on health, development, and functioning throughout the lifespan. Although studies support relations between infant sleep and individual risk factors like prenatal cortisol exposure, breastfeeding, and temperament, no known studies have examined interactive relations among these variables and long-term infant sleep outcomes, which was the current study’s aim.
Methods: Expectant mothers (n=78) provided diurnal salivary cortisol samples at 35±2 weeks gestation and returned at 6 and 14 months postpartum to complete questionnaires regarding infant behavior, health, sleep, and diet.
Results: Increased 6-month breastfeeding frequency predicted decreased 14-month sleep quality, while controlling for main/interactive effects of cortisol and temperament. Prenatal cortisol exposure and temperament had no significant main or interactive effects on 14-month sleep quality, though infants with greater 6-month Surgency/Extraversion (r=.367,p=.036) and Orienting/Regulation scores (r=.391,p=.024) had better sleep quality at 14 months.
Discussion/Conclusion: Findings replicate literature highlighting associations between greater breastfeeding frequency and poorer infant sleep quality, likely due to greater incidence of night waking and sleep location variability. Given recent literature suggesting the normalization of sleep patterns by 6 months postpartum regardless of breastfeeding status, follow-up studies should investigate factors that may account for differences in sleep trajectories.
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