title: [Maternal occupation, pregnancy length and low birth weight].
abstract: OBJECTIVE
  To assess the association between maternal occupation during pregnancy with the presence of low birth weight and preterm delivery.
  
  
  METHODS
  The sample consisted of 1,341,686 preterm infants and 1,217,897 low birth weight infants in Spain (1996-2000) with valid information on maternal occupation from the National Registry of Births. Maternal occupation was the main exposure variable coded according to groups of occupation (CNO-79) and outcomes were low birth weight (<2500 g) and preterm birth (<37 weeks). Crude and adjusted odds ratios (OR) and 95% confidence interval (CI) were calculated through the maximum verisimilitude method.
  
  
  RESULTS
  The highest prevalence of preterm infants was found in mothers working in agriculture (10.8%) and the lowest in professional women (6.6%). The highest prevalence of low birth weight was observed in the women working in the services sector (3.5%) and manual workers in industry and construction (3.4%) while the lowest prevalence was found in professional women (2.5%). Women working in agriculture had a higher risk of preterm birth than professional women (aOR=1.68; 95%CI: 1.57-1.80). The risk of low birth weight was higher in women working in the service sector (aOR=1.36; 95%CI: 1.30-1.42), housewives (aOR=1.30; 95%CI: 1.28-1.38), agricultural laborers (aOR=1.29; 95%CI: 1.14-1.44) and manual workers in industry and construction (aOR=1.29; 95%CI: 1.21-1.36).
  
  
  CONCLUSIONS
  The results of this study suggest that belonging to certain occupational groups during pregnancy could affect the risk of low birth weight and preterm birth.
authors.affiliation: Area de Medicina Preventiva y Salud Pública, Universidad de Alicante, Alicante, España. elena.ronda@ua.es
authors.forename: Elena
authors.initials: E
authors.lastname: Ronda
authors.forename: Amparo
authors.initials: A
authors.lastname: Hernández-Mora
authors.forename: Ana María
authors.initials: AM
authors.lastname: García
authors.forename: Enrique
authors.initials: E
authors.lastname: Regidor
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D009790:Occupations; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012307:Risk Factors; D055815:Young Adult