title: A firstborn boy is suggestive of a strong prognostic factor in secondary recurrent miscarriage: a confirmatory study.
abstract: OBJECTIVE
  To test our previously generated hypothesis that women with secondary recurrent miscarriages with a firstborn boy have a poorer pregnancy prognosis than those with a firstborn girl.
  
  
  METHODS
  A study of a retrospective and a prospective cohort.
  
  
  METHODS
  The Danish recurrent miscarriage clinic.
  
  
  METHODS
  Two cohorts of 175 and 130 consecutive patients with unexplained secondary recurrent miscarriage referred from 1986 to 1999 (cohort 1) and 2000 to 2005 (cohort 2), respectively.
  
  
  METHODS
  The odds ratio (OR) for a live birth in the first pregnancy after referral in those with a firstborn boy compared with a firstborn girl in each of the two cohorts. The corresponding OR for a live birth adjusted for relevant prognostic variables in the combined group of patients.
  
  
  RESULTS
  The crude ORs for a live birth in those with a firstborn boy compared with a firstborn girl were very similar in cohorts 1 and 2 (OR = 0.35, 0.33). In the adjusted analysis only two of five included variables significantly predicted live birth: a firstborn boy and the number of previous miscarriages.
  
  
  CONCLUSIONS
  Male sex of the firstborn child is a strong negative prognostic factor in women with secondary recurrent miscarriage. A possible explanation is an abnormal maternal immune response against male-specific minor histocompatibility (HY) antigens.
authors.affiliation: The Fertility Clinic, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark. henriettesvarrenielsen@hotmail.com
authors.forename: Henriette Svarre
authors.initials: HS
authors.lastname: Nielsen
authors.forename: Anne-Marie Nybo
authors.initials: AM
authors.lastname: Andersen
authors.forename: Astrid Marie
authors.initials: AM
authors.lastname: Kolte
authors.forename: Ole Bjarne
authors.initials: OB
authors.lastname: Christiansen
mesh_terms: D000026:Abortion, Habitual / Q000209:etiology* / Q000276:immunology; D000328:Adult; D005260:Female; D006182:H-Y Antigen / Q000276:immunology; D006801:Humans; D007231:Infant, Newborn; D050498:Live Birth; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011247:Pregnancy; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012744:Sex Ratio
chemical_list: D006182:H-Y Antigen