title: Changes in cotinine levels during pregnancy.
abstract: We measured maternal cotinine levels on residual sera of antenatal blood samples to biochemically document changes in smoking between early and late pregnancy. It was a random sample of 404 mothers who had both an early and late sample. Cotinine levels were used to categorize maternal smoking into nonsmoker (<15 ng/mL) and smoker (> or = 15 ng/mL) groups. Designated smokers were further partitioned into lighter (15-100 ng/mL) and heavier (>100 ng/mL) semiquantitative groupings. There was a positive cotinine result in 113 (28%) mothers in early pregnancy; of these smoking women, 35 (31%) had quit smoking by the time of their late pregnancy blood test and 28 (25%) had reduced their cotinine level by at least 25%. Many more lighter smokers had quit (59%) compared to heavier smokers (17%) (X2 = 20.9, df=1, p<0.001). By late pregnancy, 86 (21%) mothers were still defined as smokers. Almost 30% of pregnant women in this sample were smoking during early pregnancy declining to 21% in late pregnancy.
authors.affiliation: Community Paediatric Unit, Christchurch, New Zealand.
authors.forename: R P
authors.initials: RP
authors.lastname: Ford
authors.forename: P J
authors.initials: PJ
authors.lastname: Schuter
authors.forename: D M
authors.initials: DM
authors.lastname: Tappin
mesh_terms: D003367:Cotinine / Q000097:blood*; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000097:blood*; D011261:Pregnancy Trimester, First / Q000097:blood; D011262:Pregnancy Trimester, Second / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D012907:Smoking / Q000453:epidemiology
chemical_list: D003367:Cotinine