title: Placental hormone profiles as predictors of preterm birth in twin pregnancy: A prospective cohort study.
abstract: OBJECTIVE
  The objective of the study was to analyse placental hormone profiles in twin pregnancies to determine if they could be used to predict preterm birth.
  
  
  METHODS
  Progesterone, estradiol, estriol and corticotropin-releasing hormone were measured using competitive immunoassay and radioimmunoassay in serum and saliva samples of 98 women with twin pregnancies,at 3 or more gestational timepoints. Hormone profiles throughout gestation were compared between very preterm (<34 weeks; n = 8), preterm (<37 weeks; n = 40) and term (37+ weeks; n = 50) deliveries.
  
  
  RESULTS
  No significant differences were found between preterm and term deliveries in either absolute hormone concentrations or ratios. Estimated hormone concentrations and ratios at 26 weeks did not appear to predict preterm delivery. Salivary and serum hormone concentrations were generally poorly correlated.
  
  
  CONCLUSIONS
  Our results suggest that serial progesterone, estradiol, estriol and corticotropin-releasing hormone measurements in saliva and serum are not robust biomarkers for preterm birth in twin pregnancies.
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: Hui
authors.initials: H
authors.lastname: Lim
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: Sioned
authors.initials: S
authors.lastname: Powell
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: Helen C
authors.initials: HC
authors.lastname: Mcnamara
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: A Forbes
authors.initials: AF
authors.lastname: Howie
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: Ann
authors.initials: A
authors.lastname: Doust
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, John Hunter Hospital, University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Bowman
authors.affiliation: Mothers and Babies Research Centre, Hunter Medical Research Institute, John Hunter Hospital, University of Newcastle, Newcastle, New South Wales, Australia.
authors.forename: Roger
authors.initials: R
authors.lastname: Smith
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Norman
authors.affiliation: Tommy's Centre for Maternal and Fetal Health, MRC Centre for Reproductive Health, University of Edinburgh Queen's Medical Research Institute, Edinburgh, United Kingdom.|School of Women's and Infants' Health, The University of Western Australia at King Edward Memorial Hospital, Crawley Western Australia, Australia.
authors.forename: Sarah J
authors.identifier: http://orcid.org/0000-0003-4308-856X
authors.initials: SJ
authors.lastname: Stock
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D003346:Corticotropin-Releasing Hormone / Q000097:blood; D004958:Estradiol / Q000097:blood; D004964:Estriol / Q000097:blood; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007752:Obstetric Labor, Premature / Q000097:blood / Q000175:diagnosis* / Q000517:prevention & control; D010926:Placental Hormones / Q000097:blood*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D059285:Pregnancy, Twin; D011374:Progesterone / Q000097:blood; D011446:Prospective Studies; D011863:Radioimmunoassay; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010926:Placental Hormones; D011374:Progesterone; D004958:Estradiol; D003346:Corticotropin-Releasing Hormone; D004964:Estriol