title: Ecological momentary assessment of maternal cortisol profiles over a multiple-day period predicts the length of human gestation.
abstract: OBJECTIVE
  Biobehavioral models of prenatal stress highlight the importance of the stress-related hormone cortisol. However, the association between maternal cortisol levels and the length of human gestation requires further investigation because most previous studies have relied on one-time cortisol measures assessed at varying gestational ages. This study assessed whether ecological momentary assessment (EMA) of cortisol sampling improves the ability to predict the length of human gestation. In addition, associations between EMA-based measures of psychological state (negative affect) with cortisol levels during pregnancy were assessed.
  
  
  METHODS
  For a 4-day period, 25 healthy pregnant women (mean gestational age at assessment = 23.4 [standard deviation = 9.1] weeks) collected seven salivary samples per day for the assessment of cortisol and provided a rating of negative affect every waking hour using an electronic diary.
  
  
  RESULTS
  Higher salivary cortisol concentrations at awakening and throughout the day (p = .001), as well as a flatter cortisol response to awakening (p = .005), were associated with shorter length of gestation. Women who delivered an infant at 36 weeks of gestations had 13% higher salivary cortisol levels at awakening than women who delivered an infant at 41 weeks of gestation. The EMA-based measure of negative affect was associated with higher cortisol throughout the day (p = .006) but not to gestational length (p = .641). The one-time measure of cortisol was not associated with length of gestation, and traditional retrospective recall measures of negative affect were not associated with cortisol.
  
  
  CONCLUSIONS
  Our findings support the ecological validity of repeated ambulatory assessments of cortisol in pregnancy and their ability to improve the prediction of adverse birth outcomes.
authors.affiliation: Department of Psychiatry and Human Behavior, University of California, Irvine, California 92697-4260, USA. sentring@uci.edu
authors.forename: Sonja
authors.initials: S
authors.lastname: Entringer
authors.forename: Claudia
authors.initials: C
authors.lastname: Buss
authors.forename: Judith
authors.initials: J
authors.lastname: Andersen
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Chicz-DeMet
authors.forename: Pathik D
authors.initials: PD
authors.lastname: Wadhwa
mesh_terms: D000328:Adult; D000339:Affect; D002940:Circadian Rhythm / Q000502:physiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007030:Hypothalamo-Hypophyseal System; D016014:Linear Models; D008499:Medical Records; D010913:Pituitary-Adrenal System; D011247:Pregnancy / Q000378:metabolism* / Q000523:psychology; D011248:Pregnancy Complications / Q000378:metabolism* / Q000523:psychology; D047928:Premature Birth; D012463:Saliva / Q000737:chemistry*; D013315:Stress, Psychological / Q000378:metabolism*; D013997:Time Factors
chemical_list: D006854:Hydrocortisone