My mother smoked during the whole time that she was carrying me and I think I turned out all right. But one swallow doesn’t make a summer and the epidemiological evidence is unequivocal that smoking is bad both for the pregnant mother and her offspring; indeed, according to a paper in the New England Journal of Medicine for March 1st, it is the largest preventable cause in the western world of poor outcome of pregnancy for both mother and child. If my mother hadn’t smoked, therefore, I might have turned out better than I did; I always knew in my heart of hearts that my deficiencies were not really mine.
But what, exactly, is a preventable cause? Preventable by whom or by what? The question is too philosophical for a medical journal to ask, let alone answer.
The paper in the NEJM was a report of an attempt to help pregnant women quit smoking. It consisted of a double-blind trial of nicotine patches in 1050 pregnant English women who smoked heavily, i.e., more than 14 cigarettes per day, and a third of whom smoked within five minutes of waking up in the morning.
So 521 pregnant women were given nicotine patches to help them give up while 529 received placebo patches. At the end of the trial, there was no statistical difference in outcome between the two groups: nearly as many women in the group given nicotine patches still smoked as continued to do so among those in receipt of placebo patches. Only 9.4 percent of the former, and 7.6 percent of the latter, were not smoking by the time of delivery. This, of course, was a great disappointment to the researchers, though perhaps not altogether a surprise to connoisseurs of human nature.
One of the main reasons for the failure was that the women given nicotine patches simply did not comply with the treatment. Only 7.2 percent of the women given nicotine patches continued to use them for more than a month (as against 2.8 percent of those given placebo patches). In short, they did not take the prescribed treatment.
The NEJM ran an editorial to accompany this paper. This was almost comical in its lack of understanding. It said that the findings of this research were consistent with previous research:
The finding that nicotine-replacement therapy did not improve long-term quit rates in pregnancy is consistent with two other, smaller, placebo-controlled studies of nicotine gum or patches in pregnant smokers. In these studies, adherence to therapy was also low with respect to dose (number of pieces of gum per day) and duration of treatment; the average duration of use of nicotine-replacement therapy was less than 20% of the recommended duration for the patch and less than 50% of that recommended for gum.
And it went on to lament like a voice crying in the wilderness:
Adherence to therapy is a well-recognized determinant of efficacy. With low adherence rates in placebo-controlled trials of nicotine-replacement therapy in pregnant smokers, it is difficult for clinicians to counsel their patients regarding whether such treatment would be efficacious or safe if used as directed.
Of course, the human tendency to weakness of will is the problem: if it weren’t, people wouldn’t need nicotine patches in the first place.
Despite the absence of evidence that nicotine patches do any good in pregnancy, they have been widely, almost routinely, recommended. This is because the desire to do something rather than nothing is among the strongest known, if not to man, then at least to the medical profession. When in doubt, prescribe.
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