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Updated: Jun 17, 2025
Extraction and Analysis of Cortisol from Human and Monkey Hair
Published on: January 24, 2014
Neonatal Hair Cortisol and Birth Outcomes: An Empirical Study and Meta-Analysis
LillyBelle K Deer1, Catherine H Demers, Benjamin L Hankin
1From the Department of Psychology (Deer, Doom, Davis), University of Denver, Denver; Department of Psychiatry (Demers, Hoffman), University of Colorado Anschutz Medical Campus, Aurora, Colorado; Department of Psychology (Hankin), University of Illinois Urbana-Champaign, Champaign, Illinois; Department of Psychological Science (Shields), University of Arkansas, Fayetteville, Arkansas; Division of Maternal and Fetal Medicine, Department of Obstetrics and Gynecology (Hoffman), University of Colorado Anschutz Medical Campus, Aurora, Colorado; and Department of Pediatrics (Davis), University of California, Irvine, Irvine, California.
Objective:
Prenatal stress physiology is often posited as a predictor of birth outcomes, including gestational age at birth and birthweight. However, research has predominantly relied on indicators in the maternal system, with few studies examining hormones of the fetal system. The current study focuses on fetal cortisol in the third trimester, as measured in neonatal hair, as a biological factor that might be associated with birth outcomes (gestational age at birth and birthweight). We report findings from two studies: a longitudinal cohort (Study 1), and a meta-analysis of the existing literature (Study 2).
Methodsstudy:
Hair was collected for cortisol analysis from 168 neonates (55.95% female) shortly after birth. Gestational age at birth and birthweight were abstracted from medical records.
Methodsstudy:
An exhaustive search of four databases was conducted, yielding 155 total studies for screening. Papers reporting neonatal hair cortisol (collection <2 weeks postpartum) and birth outcomes among human neonates were retained for analysis, including Study 1 results ( k = 9).
Resultsstudy:
Higher neonatal hair cortisol was related to longer gestation ( r = 0.28, p < .001) and higher birthweight, r = 0.16, p = .040. Sex did not moderate either association.
Resultsstudy:
Across the nine studies, higher neonatal hair cortisol predicted both longer gestation ( r = 0.35, p < .001, 95% confidence interval = 0.24-0.45) and higher birthweight ( r = 0.18, p = .001, 95% confidence interval = 0.07-0.28). Neonatal sex did not moderate these associations.
Conclusions:
Fetal cortisol exposure in the third trimester plays a role in normative maturation of the fetus, and findings reveal that higher cortisol is associated with positive birth outcomes.
