title: Stress reduces conception probabilities across the fertile window: evidence in support of relaxation.
abstract: OBJECTIVE
  To assess salivary stress biomarkers (cortisol and α-amylase) and female fecundity.
  
  
  METHODS
  Prospective cohort design.
  
  
  METHODS
  United Kingdom.
  
  
  METHODS
  274 women aged 18 to 40 years who were attempting pregnancy.
  
  
  METHODS
  Observation for six cycles or until pregnancy: women collected basal saliva samples on day 6 of each cycle, and used fertility monitors to identify ovulation and pregnancy test kits for pregnancy detection.
  
  
  METHODS
  Salivary cortisol (μg/dL) and α-amylase (U/mL) concentration measurements; fecundity measured by time-to-pregnancy and the probability of pregnancy during the fertile window as estimated from discrete-time survival and Bayesian modeling techniques, respectively.
  
  
  RESULTS
  Alpha-amylase but not cortisol concentrations were negatively associated with fecundity in the first cycle (fecundity odds ratio=0.85; 95% confidence interval 0.67, 1.09) after adjusting for the couples' ages, intercourse frequency, and alcohol consumption. Statistically significant reductions in the probability of conception across the fertile window during the first cycle attempting pregnancy were observed for women whose salivary concentrations of α-amylase were in the upper quartiles in comparison with women in the lower quartiles (highest posterior density: -0.284; 95% interval -0.540, -0.029).
  
  
  CONCLUSIONS
  Stress significantly reduced the probability of conception each day during the fertile window, possibly exerting its effect through the sympathetic medullar pathway.
authors.affiliation: Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, Maryland 20852, USA. louisg@mail.nih.gov
authors.forename: Germaine M Buck
authors.initials: GM
authors.lastname: Louis
authors.forename: Kirsten J
authors.initials: KJ
authors.lastname: Lum
authors.forename: Rajeshwari
authors.initials: R
authors.lastname: Sundaram
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Sungduk
authors.initials: S
authors.lastname: Kim
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Lynch
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
authors.forename: Cecilia
authors.initials: C
authors.lastname: Pyper
mesh_terms: D000328:Adult; D001499:Bayes Theorem; D015415:Biomarkers / Q000378:metabolism; D016009:Chi-Square Distribution; D005260:Female; D005298:Fertility; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D007247:Infertility, Female / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D016017:Odds Ratio; D010050:Ovarian Function Tests; D010060:Ovulation; D011247:Pregnancy; D018873:Pregnancy Rate; D011258:Pregnancy Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012463:Saliva / Q000201:enzymology*; D013315:Stress, Psychological / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control; D006113:United Kingdom; D055815:Young Adult; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D000516:alpha-Amylases; D006854:Hydrocortisone