title: [Post suckling prolactin and estradiol levels as predictors of the time of appearance of the first post partum menstruation].
abstract: BACKGROUND
  The variability in the duration of lactational amenorrhoea (LA) lead to develop statistical multivariate models to predict the risk of the appearance of the first postpartum menstruation.
  
  
  OBJECTIVE
  To estimate the probability of recovering the first postpartum menstruation by means of a survival analysis, including hormonal levels and other parameters as predictor variables.
  
  
  METHODS
  Eighty one mothers in exclusive breastfeeding until the sixth postpartum month, in whom estradiol, basal and post suckling prolactin were measured at the third post partum month, were studied. The variables that better predict the appearance of the first menstruation between the 3rd and 12th postpartum months, were identified using a Cox model survival analysis.
  
  
  RESULTS
  The median amenorrhea survival time (the lapse when the chance of recovering menstruation is 50%) was 209 days from delivery. Dichotomized estradiol and post suckling prolactin were the only significant variables that predicted the return of menstruation, with cutoff points of 190 pmol/ and 2,550 mIU/L, respectively.
  
  
  CONCLUSIONS
  Post suckling prolantin and estradiol levels, measured at the third post partum month, are predictors for the time of appearance of the first postpartum menstruation.
authors.affiliation: Departamento de Obstetricia y Ginecología, Facultad de Medicina, Universidad de La Frontera, Chile. pvaldes@ufro.cl
authors.forename: Patricio
authors.initials: P
authors.lastname: Valdés
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Orellana
mesh_terms: D000328:Adult; D000568:Amenorrhea / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001942:Breast Feeding; D004812:Epidemiologic Methods; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D008598:Menstruation / Q000097:blood*; D049590:Postpartum Period / Q000097:blood*; D011388:Prolactin / Q000097:blood*; D013997:Time Factors
chemical_list: D015415:Biomarkers; D004958:Estradiol; D011388:Prolactin