A biochemical prevalence study of smoking in pregnancy for a cross-section of women in Christchurch, New Zealand.
OBJECTIVE
To biochemically measure and compare the prevalence of maternal smoking by trimester in a cross-section of pregnant women residing in Christchurch, New Zealand, during 1997.


METHODS
Residual sera from routinely collected blood samples drawn in early and late pregnancy over a 12-month period, 1 January 1997 to 31 December 1997, was accumulated and anonymously assayed. Cotinine levels were measured by an ELISA test with a result greater than 14 ng/mL indicative of active smoking.


RESULTS
Analysis was conducted upon 4,178 samples collected from 3,082 women. Adjusted cotinine validated smoking rates in the first, second and third trimesters were 26.8% (95% CI 24.5-29.2%), 25.0% (95% CI 22.3-27.8%) and 23.0% (95% CI 20.8-25.2%), respectively. This represents an absolute reduction in smoking rates of 4.7% (p = 0.02), 6.6% (p = 0.04) and 3.8% (p = 0.04) for the first, second and third trimesters, respectively, among pregnant women in Christchurch since 1994.


CONCLUSIONS
Smoke reduction and cessation programs implemented locally and nationally have been effective in significantly reducing the biochemically measured prevalence of maternal smoking in pregnancy within a three-year period.


CONCLUSIONS
Cigarette smoking during pregnancy is an important yet preventable factor affecting rates of prenatal, perinatal and paediatric morbidity and mortality. Reliable and repeated surveys of pregnant women are necessary to accurately measure changes in the maternal smoking prevalence and determine the efficacy of smoke reduction and cessation programs.
Division of Public Health, School of Population Health, University of Queensland, Herston. p.schluter@sph.uq.edu.au
P J
PJ
Schluter
R P K
RP
Ford
C J
CJ
Ford
D003367:Cotinine / Q000097:blood*; D003430:Cross-Sectional Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008429:Maternal Welfare; D009520:New Zealand / Q000453:epidemiology; D011247:Pregnancy / Q000097:blood*; D011264:Pregnancy Trimesters / Q000097:blood; D015995:Prevalence; D012907:Smoking / Q000097:blood / Q000453:epidemiology*
D003367:Cotinine