title: Preconception stress and the secondary sex ratio: a prospective cohort study.
abstract: OBJECTIVE
  To study the association between salivary stress biomarkers and the secondary sex ratio.
  
  
  METHODS
  Prospective, longitudinal cohort study.
  
  
  METHODS
  Community setting in the United Kingdom.
  
  
  METHODS
  On discontinuation of contraception for purposes of becoming pregnant, 338 women aged 18-40 years with complete data (90%) were followed until pregnant or up to six menstrual cycles.
  
  
  METHODS
  None.
  
  
  METHODS
  Secondary sex ratio.
  
  
  RESULTS
  Human chorionic gonadotropin pregnancies were detected in 207 (61%) women of whom 130 (63%) delivered singleton infants with available gender data. The adjusted odds ratio for a male birth was decreased for women in the highest quartile (AOR = 0.26; 95% confidence interval = 0.09, 0.74) of salivary cortisol relative to women in the lowest quartile during cycle 1. An inverse relation was observed between α-amylase and the 2° sex ratio, though not statistically significant.
  
  
  CONCLUSIONS
  Our findings are consistent with a reversal in the 2° sex ratio with increasing preconception salivary cortisol concentrations. This relation suggests that activation of the hypothalamus-pituitary-adrenal axis may have implications in sex allocation and requires further study.
authors.affiliation: Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA. rebecca.chason@nih.gov
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Chason
authors.forename: Alexander C
authors.initials: AC
authors.lastname: McLain
authors.forename: Rajeshwari
authors.initials: R
authors.lastname: Sundaram
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: James H
authors.initials: JH
authors.lastname: Segars
authors.forename: Cecilia
authors.initials: C
authors.lastname: Pyper
authors.forename: Germaine M Buck
authors.initials: GM
authors.lastname: Louis
mesh_terms: D000293:Adolescent; D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood; D003267:Contraception / Q000706:statistics & numerical data*; D005260:Female; D005298:Fertility / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008597:Menstrual Cycle / Q000502:physiology; D016742:Preconception Care / Q000706:statistics & numerical data*; D011247:Pregnancy; D011446:Prospective Studies; D012463:Saliva / Q000378:metabolism; D012744:Sex Ratio; D013315:Stress, Psychological / Q000453:epidemiology* / Q000378:metabolism; D061685:Time-to-Pregnancy; D055815:Young Adult; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D006063:Chorionic Gonadotropin; D000516:alpha-Amylases; D006854:Hydrocortisone