Smoking, Pregnancy and NRT

This issue is on my mind today and seems relevant to the blog because it provides a good example about vetting and applying current research to everyday life and to everyday medicine.

Firstly, cigarette smoke can affect every part of the reproductive process. Meaning that nicotine and other constituents of tobacco smoke and tobacco can affect men and women's reproductive capacity and well as the health of the unborn and born child exposed to it.

This post is not intended to cast blame or to lead you to cast blame. Most people are aware of the adverse effects of tobacco products and continue to smoke or minimize risks as a defense mechanism. They have an addiction. Other posts have dealt with tobacco addiction.

Because the US Surgeon General and many others have identified adverse outcomes from this exposure, one of the goals of Healthy People 2010 was to decrease the percent of smoking during pregnancy to a very low 2-3 % but it now stands at about 11%.

http://www.healthypeople.gov/LHI/Priorities.htm

The adverse outcomes are due to both the nicotine and carbon monoxide in cigarettes as well as some other chemicals. It is not crystal clear, and therein lies the problem. The evidence is sufficient to state a causal relationship to premature birth, low birth weight, premature rupture of membrane, placenta previa and placenta abruptia as well as SIDS. The SIDS, or sudden infant death risk lasts through the first year of life and is related to second hand smoke as well. There is also a substantial amount of evidence to support that the smoke can lead to cleft palate.

We also know that nicotine replacement therapy or NRT can double the chances that someone will quit using tobacco. The debate or dilemma comes in weighing the risk of NRT which provides nicotine vs continued smoking which sends several thousand other chemicals through the placenta into the amniotic sac and the umbilical cord . These chemicals run all through the mothers blood, to the baby. Nicotine is a neurotoxin, it can effect brain development. What does one do? Most of the medical experts I have spoken to would first suggest quitting without medicine and then say that NRT is better than continued smoking but ONLY if the NRT is the ONLY source of nicotine for that mother.

Most of the discussion is based on animal studies and older ones at that. One of the first involved pregnant rats which received far more nicotine than a woman would receive smoking OR with a patch. A more recent study used comparable nicotine doses and did not find an increase risk of low birth weight with those pups, as they're called. The studies that do exist come with a lot of weaknesses. I was especially concerned about one I read this week as I had been of the mind that NRT has to be better than continued smoking. In the new study, information was rather pieced together over what the mother's themselves reported and adverse birth outcomes were noted from birth certificates. In this study the researchers asked if the pregnant woman was a smoker or non smoker and if the mother was prescribed NRT or recommended it by the MD. This study found increased low birth weight and premature birth in the NRT group. The lowest rate was in the non smokers, but the NRT babies were worse than the babies of smokers. Here is what we do not know... did the mom's indeed use the NRT and if so, what dose and for how long? What if the Mom's who were told about it were the one's smoking the most, but they never used the NRt and or quit?

Isn't that messy?

Well, I didn't think anyone would do a placebo controlled NRT study on pregnant women but indeed there is one under way in Britain. The British National Health Service began recruitment in 2007 and will follow the women for two years, to assess the health of the children post natally. The women, who are smokers, will be given either a nicotine patch or a placebo patch. The results should be available soon and because the women are in a study, their labs will be routinely analyzed and we should know with some confidence, the result of using NRT during pregnancy.

It is not advised that women use NRT without the consultation of their physician.

I will bust one myth for you however. There is No evidence to support that quitting smoking is worse on the fetus than continuing to smoke.

Potera, C. NRT in Pregnancy. Environmental Health Perspectives. May 2007 115(5)

Gather, K. et al. Does the use of nicotine replacement therapy during pregnancy affect pregnancy outcomes. Maternal and Child Health Journal. June 2009. Viewed in Medscape.