Smoking and Pregnancy

Tobacco related deaths are numbered within the tens of thousands annually in Canada. Most lay people are aware that smoking has been linked with numerous cancers, cardiovascular disease, respiratory disease and a host of other potentially lethal diseases. However, many women who are pregnant or thinking of becoming pregnant may not be aware of the impact smoking may have on the pregnancy and on the fetus, such as spontaneous abortions, placental complications, preeclampsia, preterm and still births, fetal malformations, Sudden Infants Death Syndrome. Despite these negative health consequences, 16% to 23 % of pregnant women in Ontario smoke.

There are many reasons why women have such a hard time quitting during pregnancy. The foremost reason being that smoking is an addiction which usually requires behavioural therapy and pharmacotherapy. On their own, only 20% of smokers quit sometime during their pregnancy. Evidence demonstrates the minimal interventions provided by health professionals, coupled with self-help material tailored for pregnant women, are effective in increasing quit rates. Clinicians’ interventions have the potential to generate rates that are a 30% to 70% increase above the regular quit rates.

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"The 5 A’s", is the minimal intervention approach used in the 2000 Clinical Practice Guidelines for Physicians in the United States. Outlined below are the steps in The 5 A’s for pregnant women (Melvin, 2004);

• Advise her that quitting is important by using strong personalized messages about the risks of smoking and the benefits of quitting for herself and her unborn baby.
   

• Assess her readiness to quit in the next 30 days.
   

• Assist her in quitting by referring her to community resources for quitting, providing her with tailored quitting material, volunteering your support during the process, and suggesting she ask friends and family for support.
   

• Arrange for follow-up contact to reassess her smoking status and provide more intensive therapy if necessary.

Minimal Intervention – print-out reference sheet

(note: this reference sheet uses the Registered Nurses Association of Ontario’s 4 A’s instead of the 5 A’s. The ‘Assess’ step is incorporated into the ‘Arrange’ step.)

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For addicted smokers, behavioural therapy is not normally enough to achieve smoking cessation; pharmacological therapy is often necessary. This is just as true for pregnant women as well. Some highly addicted heavy smokers are just not able to quit when they become pregnant. Nicotine replacement therapies (NRTs) for pregnant women are not without risk. However this risk may be far less than the risk of continued smoking (Benowitz, 2004). Uteroplacental insufficiency has been the accepted key mechanism by which nicotine causes adverse outcomes. Previously it had been thought that the cardiovascular effect of nicotine reduces blood flow through the placenta causing the negative effects of smoking during pregnancy. However, researchers are now proposing that "cellular and molecular abnormalities produced by tobacco smoke toxins, acting alone or in concert, produce a wide range of adverse pregnancy outcomes" (Dempsey, 2001). In animal trials, nicotine is thought to be toxic to the development of the CNS, and it may be involved in occurrence of SIDS, nevertheless, the risks associated with nicotine must be compared to the risks associated with continued smoking (Dempsey, 2001). Continuing to smoke exposes the fetus to toxic substances including carbon monoxide, formaldehyde, arsenic, and benzoapyrene all which have negative effects in humans. The choice to use a NRT should be made on a client-to-client basis keeping these guidelines/suggestions in mind (Benowtiz, 2004)

• Use NRT for pregnant women in combination with behavioural therapy for increased success rates.
   

• Use the lowest dose of nicotine in either the patch or the gum that would be effective in achieving cessation to minimize potential fetal harm.
   

• If using the patch, 16-hour dosing is suggested as opposed to 24-hour dosing.
   

• NRT use should be introduced as early in pregnancy as possible since most of the adverse effects of smoking can be avoided if cessation occurs in the first 16 weeks of pregnancy.

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Smoking Cessation for Pregnant and Post-partum Women: A Toolkit for Health Professionals

Available at www.pregnets.org

For more information on NRT in pregnancy see:

Benowtiz NL, Dempsey, DA., Pharmacotherapy for smoking cessation during pregnancy. Nicotine & Tobacco Research. Volume 6, Supplement 2. April 2004. S189-S202.