Tobacco and secondhand smoke: Effects on pregnancy

Tobacco and secondhand smoke: Effects on pregnancy
Smoking harms fetal development and can affect your pregnancy.

Tobacco has a negative impact on pregnancy and fetal development. That’s why pregnant women are advised not to smoke. Here are answers to the most common questions about smoking during pregnancy.

Can I smoke during pregnancy?

It’s recommended not to smoke or expose yourself to secondhand smoke during pregnancy, as tobacco is harmful to fetal development. The chemicals in tobacco prevent your baby from getting everything it needs to grow properly. For example, carbon monoxide decreases the amount of oxygen the fetus receives.

Even just a few cigarettes can have negative repercussions. And the more a pregnant woman smokes, the greater the risks. The benefits to quitting smoking during pregnancy are greatest if you stop during the first trimester; however, there are still benefits to doing so even in the third trimester.

Ultimately, it’s never too late to quit smoking, or at least cut back. Even a small reduction can make a difference—the health risks for your baby will begin to decrease within just a few hours of your last cigarette.

What are the effects of tobacco on the fetus?

Smoking can have a harmful impact at every stage of pregnancy. In fact, smoking reduces your chances of getting pregnant at all. Women who smoke are more likely to experience an ectopic pregnancy, which occurs when the embryo implants in the fallopian tube rather than in the uterus. There is also a greater risk of the placenta detaching from the uterine wall or attaching too close to the cervix (placenta previa). Women who smoke are more likely to experience abnormal bleeding during pregnancy and childbirth.

Studies show that smoking during pregnancy increases the risk of the following:

Some studies also suggest that smoking while pregnant is associated with the following:

  • Damage to the baby’s brain and lungs caused by nicotine
  • Birth defects (e.g., cleft lip or palate)
  • Sudden infant death syndrome

Finally, children exposed to tobacco smoke during pregnancy are more likely to develop infections (ear infections, bronchitis, pneumonia) and asthma.

Is secondhand smoke harmful to my baby?

Secondhand smoke (i.e., smoke from other smokers) is dangerous both for a pregnant woman and herfetus.

Mothers who are exposed to tobacco smoke during pregnancy are more likely to have a low-birthweight baby. Low birthweight also means a greater risk of dying from sudden infant death syndrome (SIDS) or experiencing various health problems.

The best way to protect your health and the health of your baby is to ask those around you not to smoke in your presence, whether at home or in the car. Smokers should only smoke outside, while making sure the smoke doesn’t come indoors.

Cracking a window or using a fan while in the house or car is not enough to eliminate the harmful effects of secondhand smoke. In addition, cigarette smoke produced indoors lingers in the air, even after the cigarette is put out. This is known as thirdhand smoke.

The dangers of smoking after pregnancy

It’s best not to resume smoking after pregnancy. Smoking in the presence of children is not recommended because they breathe at a faster rate than adults and would therefore inhale more chemicals. Studies have also shown that babies and children exposed to tobacco smoke are at greater risk of ear infections, respiratory infections, asthma, and sudden infant death syndrome.

Smoking in the car is particularly harmful because it involves an enclosed space. The smoke lingers in the air longer, even if the windows are open.

Is vaping safe during pregnancy?

Some e-cigarettes contain nicotine, which can cause damage to the lungs and brain of the fetus. They also contain flavourings that can potentially be dangerous for the baby. The best option is therefore to avoid vaping while you’re pregnant.

That said, experts agree that e-cigarettes are much less harmful than traditional cigarettes. Some contain little or no nicotine, making the risks for the baby relatively low. This type of e-cigarette could be used to quit smoking, or to significantly reduce the amount of chemicals to which the fetus is exposed.

I want to quit smoking. What should I do?

Quitting smoking can be difficult, and it requires proper planning. Ideally, you should seek help before getting pregnant. The first thing to do is to speak to a health care professional. Pharmacists in particular can be a tremendous resource, and they are sometimes more accessible than physicians.

Here are some other tips you may find helpful:

It’s never too late to quit smoking. It’s a decision that will benefit your baby, no matter how far along you are in your pregnancy.
  • Write down your top reasons for quitting, ones that will give you the motivation to succeed. Here are some examples:
    • It will be good for my baby’s health
    • It will increase my chances of a healthy pregnancy
    • I’ll feel less out of breath
    • I’ll no longer smell like cigarettes
    • I’ll get fewer wrinkles
    • My skin will look healthier
    • I’ll cough less
    • I’ll save money
    • I won’t become sick when I’m older
    • I’ll have whiter teeth and fresher breath
    • Other reasons
  • Encourage your partner to quit smoking too.
  • Set a target date. Setting a date to quit smoking helps you avoid procrastinating. Choose a time when you’ll have less difficulty changing your routine.
  • Get rid of your cigarettes, lighter, ashtrays, etc. to make your environment inconducive to smoking.
  • Change your routine to avoid situations where the urge to smoke is too great.
  • Identify situations that might cause you to relapse and plan what to do if they occur.
  • Think of one or two strategies you can use to deal with withdrawal symptoms (e.g., taking a deep breath or drinking a glass of water). Think of each sudden urge to smoke as a little bridge you have to cross.
  • Find ways to control your cravings: chew on a pencil, chew gum, squeeze a stress ball, go for a walk, etc.
  • Find ways to reduce your stress.
  • Ask your partner and guests to help make your home a smoke-free environment.
  • Stay positive, even if you relapse.
  • Make a list of people you can count on and let them know you’re trying to quit.
  • Don’t hesitate to seek help.

Nicotine replacements

Some products used to quit smoking contain nicotine. Examples include patches, gum, lozenges, inhalers, and mouth sprays. It’s not a good idea to use these types of products during pregnancy because they will expose the fetus to nicotine.

However, if you’re unable to quit smoking by other means, they may be a viable option. Compared to cigarettes, these products are less harmful because they contain less nicotine and no other toxic chemicals.

Women who suffer from nausea may feel more comfortable using patches. However, it’s best to remove them at night to reduce your baby’s exposure to nicotine. Consult your pharmacist for more information.

I can’t seem to quit smoking. Can I still reduce the negative effects on my baby?

According to research, smoking fewer than 5 cigarettes a day significantly decreases the risk of having a low-birthweight baby. In addition, the risk of complications goes down as soon as it’s been a few hours since your last cigarette. In short, every cigarette you don’t smoke counts.

Smoking decreases the amount of nutrients and oxygen the baby receives. Experts suggest increasing your intake of vitamin C–rich foods to compensate for the deficiency caused by smoking. Taking prenatal multivitamins is also very important.

Avoid smoking in your home and car. This will reduce your baby’s exposure to secondhand smoke.



• I Quit Now quitline: 1-866-527-7383.
• Famille sans fumée. (French only)


Things to keep in mind

  • Smoking can be harmful to your pregnancy and fetal development.
  • Exposure to secondhand smoke can also have a negative impact on your unborn baby.
  • There are different strategies that can help you quit or cut down on smoking.


Naître et grandir

Scientific review: Dr. Catherine Dea, École de santé publique de l’Université de Montréal
Research and copywriting: The Naître et grandir team
Updated: May 2021

Photo: 123rf/ Wavebreak Media Ltd



Note: The links to other websites are not updated regularly, and some URLs may have changed since publication. If a link is no longer valid, please use search engines to find the relevant information.

  • Campbell, Katarzyna, et al. “Factors influencing the uptake and use of nicotine replacement therapy and e-cigarettes in pregnant women who smoke: A qualitative evidence synthesis.” Cochrane Database of Systematic Reviews, vol. 5, no. 5, 2020, CD013629.
  • Centers for Disease Control and Prevention. “Smoking, pregnancy, and babies.”
  • Centers for Disease Control and Prevention. “Substance use during pregnancy.”
  • Dispensaire diététique de Montréal. “Est-il possible de diminuer les effets néfastes de la cigarette sur le foetus?”
  • Gould, G. S., et al. “Exposure to tobacco, environmental tobacco smoke and nicotine in pregnancy: A pragmatic overview of reviews of maternal and child outcomes, effectiveness of interventions and barriers and facilitators to quitting.” International Journal of Environmental Research and Public Health, vol. 17, no. 6, 2020, p. 2,034.
  • Gouvernement du Québec. “The effects of smoking and second-hand smoke on health.”
  • Healthwise. “Quitting smoking and avoiding smoke during pregnancy.”
  • Institut national de santé publique. “Tabac, grossesse et allaitement.”
  • Lindson-Hawley, Nicola, et al. “Interventions to reduce harm from continued tobacco use.” Cochrane Database of Systematic Reviews, vol. 10, no. 10, 2016, CD005231.
  • Mayo Clinic. “Smoking and pregnancy: Understand the risks.”
  • NHS. “Stop smoking in pregnancy.”
  • Patnode, C. D., et al. “Interventions for tobacco cessation in adults, including pregnant persons: Updated evidence report and systematic review for the US preventive services task force.” JAMA, vol. 325, no. 3, 2021, pp. 280–298.