August 20, 2014
By Reuters Staff
NEW YORK - Nicotine patches can help women cut down on smoking while pregnant without harming the developing baby. In fact, the reduced tobacco exposure may improve child outcomes, according to two-year follow-up data on mothers and infants in the SNAP trial.
Conducted in the UK, the SNAP trial recruited 1050 pregnant smokers at 12-24 weeks' gestation who were smoking at least five cigarettes per day and assigned them to the nicotine patch or placebo patch. Both groups received behavioral smoking cessation support.
In a 2012 paper in the New England Journal of Medicine(http://bit.ly/xJpPCX), the reseachers reported that smoking cessation rates at one month were twice as high in nicotine patch users (21% vs 12% with placebo patch). However, only 9% of nicotine patch users and 8% of placebo patch users were still abstinent by the time they delivered. No safety issues were identified. (See Reuters Health Report, Feb. 29, 2012).
In a report online August 11 in Lancet Respiratory Medicine, the SNAP trialists report child development outcomes at age two for 445 infants in the nicotine patch group (88%) and 443 infants in the placebo patch group (87%).
Dr. Sue Cooper of University of Nottingham and colleagues report that infants born to nicotine patch users were more likely to have unimpaired development (i.e., no disability or problems with behavior or development) than placebo patch users (73% vs 65%, odds ratio 1.40, p=0.023).
Nicotine patch therapy during pregnancy had no effect on prolonged abstinence from smoking but did cause a temporary doubling of smoking cessation in the first month, as mentioned, which could explain the better outcomes at two years, the researchers say.
The nicotine patch group did reduce their smoking more than those in the placebo group for at least four weeks during the second trimester, which is "an important period in embryo development," they note.
They admit that they did not anticipate finding better outcomes in the infants in the nicotine patch group; "however, although less impairment was noted in children of mothers who reported greater than median adherence with nicotine patches, findings from this analysis should be considered exploratory. The observed dose-response relation could suggest a real effect, attributable to (nicotine patch therapy), but equally, alternative explanations might exist," Dr. Cooper and colleagues write. Dr. Cooper was unavailable for comment by press time.
The authors of a Comment published with the paper say it's well known that prenatal tobacco exposure increases a child's risk of low birthweight and prematurity, as well as a wide range of behavioral and developmental problems.
A strength of this study, note Dr. Maureen Black and colleagues from the University of Maryland School of Medicine in Baltimore, is the prospective assessment and the focus on child development at two years. "Although early child development is the genesis of adult health and wellbeing, many studies of smoking cessation during pregnancy terminate at delivery with the birthweight and gestational status of the newborn. By examination of children's development beyond infancy, this article generates a hypothesis by showing the need to address variability in the dose and timing of prenatal exposure to nicotine and other tobacco toxins," they write.
Going forward, they think research efforts should focus on three areas. "The first is an understanding of the mechanisms whereby smoking during pregnancy disrupts prenatal brain development and functioning; convincing evidence shows that brain disruption occurs."
The second involves investigating the effect of electronic cigarettes and other nicotine-containing vapour devices, and nicotine replacement patches used during pregnancy. And the third is developing and evaluating effective tobacco prevention and control strategies.
SOURCE: http://bit.ly/1q0cF2J and http://bit.ly/1q0cG6x
Lancet Respir Med 2014.
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