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Maternal Socioeconomic Status, Cortisol Output in Pregnancy, and Newborn Telomere Length: Differential Effects by Infant Sex

Thu, March 21, 2:15 to 3:45pm, Baltimore Convention Center, Floor: Level 3, Room 328

Integrative Statement

Introduction: Data suggest that low socioeconomic status (SES) may disrupt hypothalamic-pituitary-adrenal axis (HPAA) functioning during pregnancy. Dysregulation of the maternal HPAA during pregnancy has been linked to various offspring physical and mental health outcomes. Newborn telomere length has recently emerged as a potential biomarker of lifetime disease risk impacted by prenatal exposures. Low maternal SES has been associated with shortened newborn telomere length; proposed yet untested mechanisms of these effects include increased in utero cortisol exposure. Although various lines of research suggest potential sex differences in these effects, they are often not considered.

Aims/Hypotheses: The overall aim of this study was to examine associations among maternal SES, maternal cortisol output during pregnancy, and newborn telomere length. A secondary aim was to explore whether the magnitude and direction of any effects varied by newborn sex. We hypothesized that (a) lower SES is associated with shorter newborn telomere length; (b) lower SES is associated with greater maternal cortisol output in pregnancy; (c) greater maternal cortisol output in pregnancy is associated with shorter newborn telomere length; (d) the associations among maternal SES, prenatal cortisol exposure, and newborn telomere length are more pronounced among male than female newborns.

Study population: Hypotheses were tested in 343 sociodemographically diverse women enrolled in a prospective pregnancy cohort designed to examine the roles of maternal and child stress exposures on child development. Eligibility criteria: 1) English- or Spanish-speaking; 2) ≥ 18 years at enrollment; 3) single gestation. Exclusion criteria: 1) endorsement of ≥ 7 alcoholic drinks/week during pregnancy; 2) positive HIV status; 3) use of oral steroids in prior year. Analyses involving newborn telomere length were conducted in a subgroup (n=151) with supplemental funding.

Methods: Indicators of maternal SES (maternal education, household income) were assessed around recruitment. Newborn telomere length was assessed from cord blood samples collected at birth. Maternal HPAA functioning in pregnancy was assessed from hair collected within one week after delivery and processed using standardized methods for quantifying cortisol during each trimester of pregnancy, length of hair permitting. Analyses adjusted for relevant covariates when indicated.

Results: Lower maternal SES was associated with higher cortisol levels during each trimester among male and female infants in correlational analyses. Males and females differed significantly in their pattern of association between maternal SES and newborn telomere length in correlation coefficient difference tests, with maternal SES associated with shorter telomere length among males and tending to be associated with longer telomere length among females. Males and females also differed significantly in their pattern of association between maternal hair cortisol levels and newborn telomere length in multi-group structural equation modeling analysis, with a negative association among males and a positive, significant association among females. These results suggest that maternal SES may have intergenerational consequences via disruptions to the maternal-fetal HPAA that influence newborn telomere length. Sex may moderate the magnitude and direction of effects. These findings have implications for elucidating mechanisms contributing to health disparities among socioeconomically disadvantaged populations, with possible sex-specific effects.

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