Tobacco smoke and pregnancy

Exposure to second-hand smoke during pregnancy poses serious risks for the pregnant person and their baby.

Second-hand smoke

Second-hand smoke is the smoke that comes from a burning tobacco product and the smoke exhaled by a person who is smoking. Many of the chemicals in tobacco smoke are therefore also found in second-hand smoke.

In Canada, an estimated 22% of those who do not smoke are exposed to second-hand smoke every day or almost every day.^{Footnote 1}^{Footnote 2} Children and adolescents have the highest measurable exposure to second-hand smoke among those exposed in the home.^{Footnote 1}^{Footnote 2}

Second-hand smoke increases health risks to you and your baby

There is no safe level of exposure to second-hand smoke. Even brief exposure can be harmful to health.^{Footnote 3}^{Footnote 4}^{Footnote 5} Nicotine, cancer-causing chemicals, and toxic chemicals found in tobacco smoke enter the body when someone breathes in second-hand smoke.^{Footnote 5}^{Footnote 6} During pregnancy, many chemicals found in second-hand smoke can pass to the baby through the placenta.^{Footnote 7}

Nicotine in the bloodstream during pregnancy can affect the function of the placenta and decrease blood flow to the developing baby.^{Footnote 5} This negative outcome can affect the developing baby's heart, lungs, digestive system, and central nervous system.^{Footnote 8} Carbon monoxide, a toxic substance in cigarette smoke, can slow the baby's growth and lead to low birth weight.^{Footnote 5}

Pregnant people exposed to second-hand smoke are also at a higher risk for problems with childbirth.

Pregnant people and their babies

Smoking tobacco during pregnancy results in serious risks for both the person who smokes and their baby and can increase the risk of complications, such as:

low birth weight
stillbirths
decreased fetal growth
premature births
placental abruption
sudden infant death syndrome (SIDS)

Exposure to second-hand smoke can also put a fetus at risk of developing health problems during childhood, such as leukemia, lymphomas and brain tumors.

Infants and children

Second-hand smoke is especially dangerous for babies and children. Their lungs are still developing and are not as strong as those of adults. Increased health risks from second-hand smoke include:

asthma
ear infections
acute respiratory infections: pneumonia and bronchitis
respiratory symptoms: coughing, wheezing, and shortness of breath
sudden infant death syndrome (SIDS): chemicals in second-hand smoke appear to affect the brain in ways that interfere with its regulation of an infant's breathing

How to lower the health risks to you and your baby

Preventive measures reduce the risk to your baby, such as:

avoiding smoking during and after pregnancy
avoiding exposure to second-hand smoke during and after pregnancy
keeping the baby away from tobacco smoke in all enclosed spaces such as:
- in the home
- in a vehicle
- in recreational settings
- near entrances to buildings
- at work
- anywhere else the baby spends time

The following actions do not eliminate exposure to second-hand smoke nor its associated health risks:

cleaning or filtering the indoor air
increasing ventilation
segregating smoking areas^{Footnote 3}

The only solution to protect your health and the health of your infant or child is to eliminate smoking in all enclosed spaces and to avoid areas where there are people who smoke.

Health benefits of quitting tobacco use at any age

Quitting tobacco use reduces the risk of premature death, improves health, and enhances quality of life.^{Footnote 9} Quitting at any age is beneficial to one's health.^{Footnote 9} Even people who have smoked or used tobacco heavily for many years benefit from it.^{Footnote 9}^{Footnote 10} Quitting is the most important thing someone who smokes can do to improve their health.

For help to quit

Read more about the benefits of quitting smoking.

Free quit counselling, coaching and other services in your province or territory

Find services to quit smoking

End Notes

Footnote 1

Wong SL, Malaison E, Hammond D, Leatherdale ST. Secondhand smoke exposure among Canadians: cotinine and self-report measures from the Canadian Health Measures Survey 2007–2009. Nicotine & Tobacco Research. 2013;15(3): 693–700. https://doi.org/10.1093/ntr/nts195.

Return to footnote 1 referrer

Footnote 2

Levesque J, Mischki T. Exposure to tobacco smoke among Canadian nonsmokers based on questionnaire and biomonitoring data. Health Reports. 2021. doi: https://www.doi.org/10.25318/82-003-x202100200002-eng.

Return to footnote 2 referrer

Footnote 3

U.S. Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centres for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006.

Return to footnote 3 referrer

Footnote 4

U.S. Department of Health and Human Services. The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2014.

Return to footnote 4 referrer

Footnote 5

U.S. Department of Health and Human Services. A Report of the Surgeon General: How Tobacco Smoke Causes Disease The Biology and Behavioral Basis for Smoking-Attributable Disease. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2010.

Return to footnote 5 referrer

Footnote 6

International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans: Tobacco Smoke and Involuntary Smoking. Vol. 83. Lyon (France): International Agency for Research on Cancer, 2004.

Return to footnote 6 referrer

Footnote 7

Lee M, Ha M, Hong Y, Park H, Kim Y, Kim EJ, Kim Y, Ha E. Exposure to prenatal secondhand smoke and early neurodevelopment: Mothers and Children's Environmental Health (MOCEH) study. Environmental Health. 2019;18(1): 22. doi: 10.1186/s12940-019-0463-9.

Return to footnote 7 referrer

Footnote 8

Fajersztajn L, Veras MM. Hypoxia: From placental development to fetal programming. Birth Defects Research. 2017;109(17):1377-1385. doi: 10.1002/bdr2.1142.

Return to footnote 8 referrer

Footnote 9

U.S. Department of Health and Human Services. Smoking Cessation: A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2020.

Return to footnote 9 referrer

Footnote 10

U.S. Department of Health and Human Services. The Health Consequences of Smoking. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2004.

Return to footnote 10 referrer

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Date modified:: 2024-07-19

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