title: S-relaxin as a predictor of preterm delivery in women with symptoms of preterm labour.
abstract: OBJECTIVE
  To evaluate whether serum relaxin (S-relaxin) can predict spontaneous delivery before 34 weeks of gestation in high risk pregnancies.
  
  
  METHODS
  A prospective cohort study.
  
  
  METHODS
  Calculated sample size was reached over a two-year period, during which 9507 women gave birth. Of these, 157 healthy women were eligible for the study as they were admitted with symptoms of delivery before 34 weeks of gestation. Ninety-three women were included. Overall participation rate was 59%.
  
  
  METHODS
  Healthy women with singleton pregnancies with symptoms of delivery before 34 weeks of gestation.
  
  
  METHODS
  S-relaxin was measured using a standard sandwich ELISA.
  
  
  METHODS
  End points were preterm delivery before 34 weeks of gestation and delivery within three days from initiation of symptoms. The best possible prediction of preterm delivery was established using logistic regression for risk factors individually associated with preterm delivery before 34 weeks of gestation. S-relaxin was dichotomised to obtain best possible fit and then entered into the model. The same analyses were done for delivery within three days.
  
  
  RESULTS
  Median S-relaxin levels varied significantly in the women with preterm prelabour rupture of membranes (PPROM) (316 pg/mL), contractions (222 pg/mL) or ripe cervices (203 pg/mL) (P < 0.05). S-relaxin above the 80th centile (> or = 300 pg/mL) was associated with an increased risk of preterm delivery [crude OR = 4.8; (95% CI: 1.9-12)]. Likelihood ratio of a positive test is 2.6 (1.5-4.9) and S-relaxin resulted in a post-test probability of preterm delivery of 0.72, compared with a pre-test probability of 0.49. S-relaxin contributed to the identification of delivery within three days [adj. OR = 11 (95% CI: 1.8-64)].
  
  
  CONCLUSIONS
  S-relaxin may be a useful predictor in women with symptoms of delivery before 34 weeks of gestation.
authors.affiliation: Department of Obstetrics and Gynaecology, Aarhus University Hospital, Denmark.
authors.forename: Ida
authors.initials: I
authors.lastname: Vogel
authors.forename: Marianne
authors.initials: M
authors.lastname: Glavind-Kristensen
authors.forename: Poul
authors.initials: P
authors.lastname: Thorsen
authors.forename: Franz P
authors.initials: FP
authors.lastname: Armbruster
authors.forename: Niels
authors.initials: N
authors.lastname: Uldbjerg
mesh_terms: D015992:Body Mass Index; D016009:Chi-Square Distribution; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000097:blood; D005865:Gestational Age; D006801:Humans; D007752:Obstetric Labor, Premature / Q000175:diagnosis*; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood; D011446:Prospective Studies; D012065:Relaxin / Q000097:blood*
chemical_list: D012065:Relaxin