title: [Social-economic and obstetric factors associated to premature rupture of membranes].
abstract: BACKGROUND
  The premature rupture of membranes is the delivery of amniotic liquid after 20 weeks of gestation and before the beginning of labour.
  
  
  OBJECTIVE
  To evaluate the association between premature rupture of membranes and sociodemographics and obstetrics antecedents.
  
  
  METHODS
  Unmatched case-control study carried out in patients from Hospital Civil de Culiacan, Sinaloa (Mexico), from January 2003 to December 2006. Risk factors frequency was compared in women with and without premature rupture of membranes (cases: 1,399; controls: 1,379). Most important variables were: socio-economic level, smoking, and gyneco-obstetric history (sexual partners, pregnancies, newborns, abortions, prenatal control and intergenesic interval). Odds ratio, crude and adjusted, and interval of confidence (IC 95%) were obtained by means of non-conditional logistic regression models.
  
  
  RESULTS
  Prevalence of premature rupture of membranes was 8.9%. Socio-economic level was similar in both groups. Premature rupture of membranes was associated with smoking, beginning of sexual activity, and intergenesic interval. History of two or more cesarean sections was considered a protective factor of premature rupture of membranes. Number of sexual partners was marginally meaningful (p = 0.053). Preterm birth frequency was higher in cases group. Resolution of pregnancy was the same for both groups (p = 0.233).
  
  
  CONCLUSIONS
  Premature rupture of membranes was significantly associated with smoking, beginning of sexual activiti, intergenesic interval and a preterm birth history. Two or more previous caesarean sections were considered as protective factor.
authors.affiliation: Facultad de Medicina, Universidad Autónoma de Sinaloa, México. fmorganortiz@hotmail.com
authors.forename: Fred Morgan
authors.initials: FM
authors.lastname: Ortiz
authors.forename: Yamel Gómez
authors.initials: YG
authors.lastname: Soto
authors.forename: Valenzuela González Irela
authors.initials: VG
authors.lastname: del Refugio
authors.forename: Aurelio González
authors.initials: AG
authors.lastname: Beltrán
authors.forename: Everardo Quevedo
authors.initials: EQ
authors.lastname: Castro
authors.forename: Ignacio Osuna
authors.initials: IO
authors.lastname: Ramírez
mesh_terms: D016022:Case-Control Studies; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D011247:Pregnancy; D012307:Risk Factors; D012959:Socioeconomic Factors; D055815:Young Adult