title: Smoking during pregnancy measured by population cotinine testing.
abstract: OBJECTIVE
  To establish a baseline cross-sectional prevalence of maternal smoking, measured by antenatal serum cotinine testing, in a population of pregnant women.
  
  
  METHODS
  Residual sera from first and second routine antenatal blood samples were collected anonymously over a six-month period for pregnancies within the Canterbury region. Cotinine levels were measured by an ELISA test with a result of > 14 ng/mL indicative of active smoking. Only pregnancies ending in a confirmed live birth were considered in smoking prevalence calculations. There was a total of 1948 eligible residual blood samples.
  
  
  RESULTS
  Of the 414 residual blood samples available for the first two months of pregnancy, 146 (35.3%) were found to be positive for cotinine. Smoking prevalence decreased over pregnancy so that by the third trimester 225 (26.8%) of 838 samples were cotinine positive. Infants born from smoking mothers had significantly lower birth weights.
  
  
  CONCLUSIONS
  In 1994, a third of women tested in early pregnancy and a quarter of women tested in late pregnancy were identified as being smokers. Repeated objective cross-sectional surveys will allow accurate assessment of the efficacy of smokefree interventions both before and during pregnancy.
authors.affiliation: Community Paediatric Unit, Healthlink South, Christchurch.
authors.forename: D M
authors.initials: DM
authors.lastname: Tappin
authors.forename: R P
authors.initials: RP
authors.lastname: Ford
authors.forename: P J
authors.initials: PJ
authors.lastname: Schluter
mesh_terms: D001724:Birth Weight; D003367:Cotinine / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D009520:New Zealand / Q000453:epidemiology; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D015995:Prevalence; D012907:Smoking / Q000453:epidemiology*
chemical_list: D003367:Cotinine