Smoking During Pregnancy: Effects on Fetal Health and Interventions

Introduction: Smoking and Pregnancy Risks

It is generally agreed that smoking may lead to numerous, serious health-related complications — and these complications are not limited to the smoker alone. Secondhand smoke, for example, can greatly affect third parties. More importantly, smoking during pregnancy can have negative effects on the health of the unborn baby. One common problem is the occurrence of spontaneous abortions. Several studies have demonstrated that tobacco use is a major factor in causing spontaneous abortions among pregnant smokers.

Studies have also shown that smoking during pregnancy can pose several other threats to fetal health. Even secondhand smoke can be dangerous to the fetus, having been cited as a cause of early pregnancy loss. Specifically, secondhand smoke is most often connected to sudden infant death syndrome (SIDS). Studies have shown that infants who die from SIDS typically have had higher concentrations of nicotine and cotinine in their lungs. Cotinine is a biological marker for exposure to secondhand smoke. Although smoking while pregnant certainly increases the risk of SIDS, infants exposed only to secondhand smoke are actually at greater risk for the condition than those whose mothers smoked directly during pregnancy.

Clearly, smoking — or even just being exposed to smoke during pregnancy — can have serious, even deadly, health effects on a fetus. Fully understanding the potential threats that smoking during pregnancy can cause is essential knowledge for any nurse. With a clear understanding of these effects, a nurse will be better able to explain the risks to patients and thus potentially limit some of the complications. The following in-depth literature review is presented to assist with that understanding.

England, Lucinda J., Kendrick, Juliette S., Wilson, Hoyt G., Merritt, Robert K., Gargiullo, Paul M., and S. Christine Zahniser. (2001): "Effects of Smoking Reduction During Pregnancy on the Birth Weight of Term Infants." American Journal of Epidemiology. Vol. 154, No. 8: 694–701.

This research was conducted by leading health care professionals and examined whether reducing tobacco exposure during pregnancy increases birth weight of term infants, and the relative effects of early versus late pregnancy tobacco exposure on infant birth weight. Data were gathered from the Smoking Cessation in Pregnancy project, conducted in public clinics in Colorado, Maryland, and Missouri between 1987 and 1991, involving 1,583 pregnant smokers. The results showed that reducing cigarette use is associated with an increase in mean infant birth weight, leading to the conclusion that women who smoke during pregnancy may need to reduce their use in order to improve their infant's birth weight.

Effects on Fetal and Infant Health

Sadowski, Kelly, and Thomas G. Parish. (2005): "Maternal Smoking Contributes to the Development of Childhood ADHD." The Internet Journal of Allied Health Sciences and Practice. Vol. 3, No. 1.

This study was conducted by two leading health care providers through a review of literature concerning maternal cigarette smoking during pregnancy. The review was performed using Medline, CINAHL, and PubMed. It concluded that there is a link between smoking during pregnancy and increased incidences of behavioral disorders — specifically Attention Deficit Hyperactivity Disorder (ADHD) — however, a direct causative relationship was not established.

Fellows, J.L., Trosclair, A., and Adams, E.K. (2002): "Annual Smoking-Attributable Mortality, Years of Potential Life Lost, and Economic Costs — United States, 1995–1999." MMWR Weekly. 51(14); 300–303.

This study reviewed the mortality rate of children exposed to a smoking mother during pregnancy. It was conducted by several PhD-level researchers reviewing mortality rates found in medical records across the nation. According to the findings, over 599 male infants were killed as a result of their mothers smoking during pregnancy.

Cornelius, Marie D. and Nancy L. Day. (2000): "The Effects of Tobacco Use During and After Pregnancy on Exposed Children." Relevance of Findings for Alcohol Research. Vol. 24, No. 4.

This study was conducted by two PhD-level professors of health studies and consisted of a literature review of various studies designed to better understand the effects of prenatal tobacco exposure, so that caregivers could more effectively identify its characteristics and better address the unique needs of affected children. The study concludes that tobacco use during pregnancy negatively affects the fetus, and that preventing various forms of substance use during pregnancy — as well as treating children affected by prenatal substance exposure — is beneficial to the well-being of the child.

Moner, S.E. (1994): "Smoking and Pregnancy." Canadian Guide to Clinical Preventive Health Care. Ottawa: Health Canada; pp. 26–36.

Intervention Strategies for Pregnant Smokers

This research was conducted by the Canadian Task Force on the Periodic Health Examination. The study examined not only the effects of smoking during pregnancy, but — more importantly — which steps are most effective in preventing pregnant mothers from smoking. It was conducted using a combination of literature review, personal consultations, and records review. The results found that advice, multi-component programs, behavioral strategies, repeated contacts, and self-help manuals are all effective in significantly decreasing tobacco smoking among pregnant women.

Bailey, Diane, Taylor, Polly, and Jeanette Zaichkin. (2002): Smoking Cessation During Pregnancy: Guidelines for Intervention. Washington State: Maternal and Child Health Division of the State Department of Health.

This study was conducted by three nurse practitioners in the state of Washington. The research focused on identifying the best methods of effective intervention for smoking mothers in order to reduce the effects of smoking during pregnancy on the infant. The study was a review of all intervention methods used throughout the state. It concludes that the most effective intervention tool for a pregnant woman who smokes fewer than twenty cigarettes per day is the Brief Intervention method.

Solomon, Laura J. and Virginia P. Quinn. (2003): "Spontaneous Quitting: Self-Initiated Smoking Cessation in Early Pregnancy." Nicotine and Tobacco Research. Vol. 6, Sup. 2; S203–S216.

This study examined the phenomenon of self-initiated smoking cessation during early pregnancy, contributing to the broader understanding of how and when pregnant women are most likely to quit on their own, independent of formal intervention programs.

Benowitz, Neal L. and Delia A. Dempsey. (2004): "Pharmacotherapy for Smoking Cessation During Pregnancy." Nicotine & Tobacco Research. Volume 6, Supplement 2.

Conclusion

The literature presented clearly shows that smoking during pregnancy has an adverse effect on infants and fetuses, and that through proper treatment and counseling, these effects can be mitigated either before they happen or after the infant is born. However, the literature review also reveals that research conducted thus far is limited in one significant respect: there is no conclusive evidence as to the best method for preventing smoking during pregnancy. Therefore, future research should focus not on documenting what the effects are — as this is already well established — but on how best to support pregnant mothers in ceasing to smoke.