Testing Associations between Prenatal Stress, Infant Sleep Characteristics, Breastfeeding, and Child Physical Growth over the First Years of Life

• In Event: Infant sleep and the development of obesity: Direct and indirect associations in four longitudinal cohorts

Abstract

According to the fetal programming hypothesis, prenatal experiences can lead to a reorganization of physiological processes that have long-term effects on health and development (Barker, 2004; Gluckman et al., 2010). A commonly studied prenatal experience that has been linked to alterations in infant outcomes is prenatal stress (Buffa et al., 2018). Prenatal stress has been associated with increased risk for adverse birth outcomes related to physical growth (Ding et al., 2021; Walsh et al., 2019) as well as sleep problems in childhood (O’Connor et al., 2007; Simcock et al., 2019), which is a risk factor for obesity (Taveras et al., 2008). The current study examined the associations between maternal prenatal stress, infant birth characteristics, infant sleep at 6 months of age, and toddler growth percentiles at 18 months of age. Further, because prior research has demonstrated that breastfeeding influences both infant sleep and physical growth (Galbally et al., 2013; Wallenborn et al., 2021), we explored if breastfeeding moderated the associations between prenatal stress and these outcomes.

Data comes from the Brain and Early Experience (BEE) study, a longitudinal study of 203 diverse mother-infant dyads (Mills-Koonce et al., 2022). Of the mothers recruited, 33% identified as Black/African American, 8.9% as Hispanic/Latina, and 38% reported incomes-to-needs ratios of <2.0. Prenatal stress was assessed using the Perceived Stress Scale (Cohen et al., 1983) and the Economic Strain Questionnaire (Conger & Elder, 1994). Birth characteristics were collected via maternal report. When infants were 6 months, breastfeeding status was collected via maternal report and infant sleep was indexed using up to 7 nights of actigraphy monitoring. Toddler growth percentiles for age were calculated when children were 18 months old using the Baby Infant Growth Chart Calculator provided by the CDC (2008).

Preliminary findings are based on a sub-sample of dyads for which actigraphy data are processed (N=37); standardized effect estimates are reported. Using multiple linear regression and adjusting for breastfeeding status, maternal education, maternal BMI, and child’s age at the 6-month visit, prenatal economic strain was associated with reduced longest sleep period (β=-0.37, p=.025), sleep duration (β=-0.38, p=.036), and nighttime sleep ratio (β=-0.44, p=.021), and increased infant night wakings (β=0.39, p =.036). There were no significant associations between economic strain and birth characteristics or toddler growth, or between infant sleep and toddler growth. There also were no significant associations between prenatal perceived stress and infant sleep; though, perceived stress was marginally associated with decreased birthweight (β=-0.14, p =.053) and increased toddler growth (β=0.49, p =.054). Breastfeeding did not moderate the associations between economic strain and infant sleep characteristics. However, the interaction effect of prenatal perceived stress and breastfeeding was trending towards significance (β=-0.68, p=.088), such that the effect of perceived stress on increased toddler growth was only present for children that were not breastfed (p=.015).

Though preliminary, these findings provide insight into the very early determinants of health disparities and targets for interventions surrounding maternal and child health. 158 participants provided actigraphy data, which will be processed by the time of the SRCD Biennial Conference.

Authors

• Kirsten McLaughlin, University of North Carolina at Chapel Hill
  Presenting Author

• Amanda Wylie, University of North Carolina at Chapel Hill

• Sarah J Short, University of Wisconsin - Madison

• Cathi Propper, University of North Carolina at Chapel Hill