PRO & CON.

Should nicotine replacement therapy be used during pregnancy?

YES

Women who smoke during pregnancy assume a large risk of serious complications. Some women do quit smoking during pregnancy, but many don't, and those who do not quit tend to be the more addicted women. Behavioral programs do help a bit, but they don't help the more addicted smokers. Experience with nonpregnant women shows that nicotine replacement therapy is useful in helping people quit, especially the more highly addicted smokers. So it makes sense that some kind of medication to help pregnant women stop smoking would be worthwhile.

On the other hand, nicotine itself can potentially harm the fetus. The issue of nicotine replacement therapy during pregnancy clearly requires a careful analysis of the relative risks and benefits. With Dr. Delia A. Dempsey, I have recently published an article reviewing these risks and benefits (Drug Safety, 24[4]:277-322, 2001).

My argument for nicotine replacement therapy has three elements. First, in most cases you're not exposing the woman to any more nicotine than she's getting as a result of smoking, maybe less. Second, you're exposing them in a way that's less hazardous to them. That is, inhaling nicotine in smoke results in higher arterial blood levels and more intense physiologic responses, compared with nicotine taken from pharmaceutical preparations. Third, cigarette smoke contains many toxic substances aside from nicotine, including carbon monoxide, a well-known teratogen that causes abnormalities in brain development. It contains oxidant gasses that can affect blood vessels in the placenta and fetus, and it contains heavy metals that can have adverse effects on fetal brain development.

I acknowledge that nicotine replacement therapy in pregnancy has not been proven to increase cessation rates. The one published study on this did not show a difference in cessation rates, although it did show an improvement in birthweights in the children who received nicotine, which may be a result of their mothers having smoked fewer cigarettes (Obstet. Gynecol. 96[6]:967-71, 2000). The benefits, although theoretical, have not been demonstrated, and this dearly needs to be studied further.

The mode of nicotine replacement therapy may make a difference. If you look at the trials with the gum, the transdermal patch, the inhaler, and the nasal spray, they all increase cessation rates about twofold over placebo. But the average amount of nicotine absorbed is quite different. For the patch, the average absorbed dose is between 15 mg and 21 mg; for the other forms, it's about 10 mg.