Correspondence

Use of the Nicotine Patch by Pregnant Women

N Engl J Med 1999; 341:1700November 25, 1999

Article

To the Editor:

Even if women acknowledge the perinatal risks of cigarette smoking and wish to quit the habit, many women continue to smoke after realizing that they have conceived.1 The transdermal nicotine patch, when combined with counseling, is an effective method of nicotine replacement.2 However, nicotine has been shown to be teratogenic in animal studies, and it is categorized by the Food and Drug Administration at risk level D, which implies substantial risk to the fetus.3,4 This has led clinicians and pharmaceutical companies to hesitate and largely to ignore the potential opportunity offered by the transdermal nicotine patch for helping pregnant women protect their unborn children.

We hypothesized that use of the transdermal nicotine patch by pregnant women would prevent exposure of the fetus to the scores of other toxins besides nicotine that are present in tobacco smoke, such as carbon monoxide, cyanide, and thiosulfate. However, to justify this approach, it must be ensured that women are exposed to less nicotine than they would be from continued smoking.

In a pilot phase of a randomized, placebo-controlled trial of use of the transdermal nicotine patch during pregnancy, we measured serum and salivary levels of nicotine and cotinine at base line and after use of the patch for one week in a group of women who smoked. Serum cotinine levels decreased in six of the seven pregnant women studied and remained unchanged in one. The mean serum cotinine level decreased from 247.6±96.9 ng per milliliter at base line to 163.7±72.9 ng per milliliter after use of the patch (P=0.003 by the two-tailed t-test). Salivary cotinine levels showed a similar trend (449.4±233.4 ng per milliliter at base line and 197.7±114.2 ng per milliliter after use of the patch for one week, P=0.02). Because of the relatively long elimination half-life of cotinine (approximately 20 hours), weekly monitoring of cotinine levels can ensure that systemic exposure of the fetus to this xenobiotic remains lower than it would have been with continued smoking. To ensure fetal safety further, the use of a 16-hour patch can mimic the use of cigarettes on a typical day followed by 8 hours of sleep, so that nicotine levels at night will be no higher than would be the case with smoking.

If cotinine levels increase while a woman is using the transdermal nicotine patch, its dose can be decreased, and studies should be performed to verify whether and how much the woman is smoking. Measurement of thiosulfate and carbon monoxide levels can distinguish smoking from use of the transdermal nicotine patch.

The ethical and practical challenge is to help women who are unable to stop smoking during pregnancy to do so with use of the nicotine patch, without encouraging the use of the patch by women who are able to stop smoking on their own. The method we propose overcomes the chief hurdle blocking use of the transdermal nicotine patch during pregnancy and may lead to a decrease in the perinatal morbidity and mortality caused by smoking tobacco during pregnancy.

Richard Hackman, M.D.
Bhushan Kapur, Ph.D.
Gideon Koren, M.D.
Hospital for Sick Children, Toronto, ON M5G 1X8, Canada

4 References

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   Lambers DS, Clark KE. The maternal and fetal physiologic effects of nicotine. Semin Perinatol 1996;20:115-126
   CrossRef | Web of Science | Medline

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   Reid RD, Pipe A, Dafoe WA. Is telephone counselling a useful addition to physician advice and nicotine replacement therapy in helping patients to stop smoking? A randomized controlled trial. Can Med Assoc J 1999;160:1577-1581
   Web of Science

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   Drug information for the health care professional. 15th ed. Vol. 1. Rockville, Md.: United States Pharmacopeial Convention, 1995.
   

4. 4

   Benowitz NL. Nicotine replacement therapy during pregnancy. JAMA 1991;266:3174-3177
   CrossRef | Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   Brian Chan, Adrienne Einarson, Gideon Koren. (2005) Effectiveness of Bupropion for Smoking Cessation During Pregnancy. Journal of Addictive Diseases 24:2, 19-23
   CrossRef

2. 2

   B Kapur. (2001) Randomized, double-blind, placebo-controlled trial of nicotine replacement therapy in pregnancy. Current Therapeutic Research 62:4, 274-278
   CrossRef