title: Elevated mid-trimester maternal corticotrophin-releasing hormone levels in pregnancies that delivered before 34 weeks.
abstract: OBJECTIVE
  To test whether maternal corticotrophin-releasing hormone levels are elevated in the mid- trimester for those women who subsequently had spontaneous preterm delivery and to assess the clinical utility of the measurement in the prediction of preterm delivery.
  
  
  METHODS
  A prospective observational study.
  
  
  METHODS
  Department of Obstetrics and Gynaecology, Prince of Wales Hospital, Hong Kong.
  
  
  METHODS
  1047 low risk pregnant women recruited at 15-20 weeks of gestation.
  
  
  METHODS
  Venous samples were assayed for levels of corticotrophin-releasing hormone. The investigators responsible for the laboratory assay were blinded to the obstetric outcome.
  
  
  METHODS
  Incidence of preterm, term and post-term pregnancies.
  
  
  RESULTS
  Those who were delivered spontaneously at a preterm gestational age (before 34 weeks) had significantly higher corticotrophin-releasing hormone levels in the mid-trimester, compared with those who were delivered at term or post-term. There was a trend towards lower corticotrophin-releasing hormone levels with more advanced gestational age at delivery. When the measurement of corticotrophin- releasing hormone was used to predict delivery before 34 weeks, the best cut off was 1.9 MoM, which produced a sensitivity of 72.7% and specificity of 78.4%. This translated to a positive predictive value of 3.6%, negative predictive value of 99.6% and relative risk of 9.4 when the background prevalence of spontaneous preterm delivery before 34 weeks was 1.1%. The likelihood ratio was 3.4.
  
  
  CONCLUSIONS
  Mid-trimester maternal corticotrophin-releasing hormone levels are elevated in pregnancies destined to deliver preterm before 34 weeks. When used alone in a low risk population, the measurement has a low predictive power for preterm delivery. However, the likelihood ratio of 3 4 implies that in high risk populations the test may be considerably more valuable.
authors.affiliation: Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin.
authors.forename: T N
authors.initials: TN
authors.lastname: Leung
authors.forename: T K
authors.initials: TK
authors.lastname: Chung
authors.forename: G
authors.initials: G
authors.lastname: Madsen
authors.forename: M
authors.initials: M
authors.lastname: McLean
authors.forename: A M
authors.initials: AM
authors.lastname: Chang
authors.forename: R
authors.initials: R
authors.lastname: Smith
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000097:blood*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000097:blood; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D003346:Corticotropin-Releasing Hormone