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Effects of smoking & second-hand smoke on pregnancy


  • Babies of smokers are twice as likely to die of SIDS (Sudden Infant Death Syndrome)External Link
  • Pregnant non-smokers who live with smokers are more likely to have a baby that weighs too little and may have health problems.
  • It is easier for a pregnant smoker to quit if those around her do not smoke.
  • Babies of smokers who quit early in pregnancy do as well as babies of non-smokers.
  • People who stop smoking have more money to spend on themselves.

Smoking and being exposed to second-hand smoke is dangerous to your health and the health of your unborn baby. Many people do not realize that smoking before pregnancy External Link has an impact on your chances of getting pregnant.

If you smoke and you are pregnant, it is important that you try to quit. Every puff of smoke you inhale, your baby inhales. This section provides you with resources and links to information/services that can help you quit smoking.

In Halton, the Health Department operates the The Stop Smoking Clinic, a free service that provides smokers with individual counselling with a doctor or health care professional who can help smokers make changes in their life that will help them quit smoking.

How does smoking affect my unborn baby?

  • When you smoke, the chemicals from cigarette smoke get into your unborn baby's blood so your unborn baby gets 25% less oxygen, does not grow properly and is less healthy.
  • The placenta joins mom and baby - food and oxygen go from Mom's blood to baby through the placenta. Nicotine can cross the placenta thereby decreasing blood flow to the fetus and affecting the fetal cardiovascular system, gastrointestinal system and central nervous system. Pregnant smokers have placentas that do not work as well as they could.
  • Every time you have a cigarette, your baby gets less food and oxygen.
  • Babies of smokers are more likely to be born prematurely.
  • Babies of smokers do not grow as well as they could due to the carbon monoxide. This results in a baby with low birth weight.

If you smoke while you are pregnant you are more likely to:

  • Have problems during your pregnancy.
  • Have a miscarriage.
  • Deliver the baby too soon.
  • Have a baby of low birth weight.
  • Have problems in labour or delivery.
  • Lose your baby during childbirth.
  • Have a baby born with lungs that are not developed properly.
  • Have a baby who suffers from bronchitis, pneumonia, and/or asthma.
  • Have a baby who is weak, unhealthy, or cries more often.
  • Have your baby die suddenly while sleeping (Sudden Infant Death Syndrome).
  • Have a child with learning difficulties and behavioural problems.
  • Have a child that may show symptoms of Attention Deficit Hyperactivity Disorder (ADHD).

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Does my partner’s smoking habits have an affect on the health of the unborn baby?

  • Yes –even if you are not smoking, when you are exposed to second-hand smoke, you have a greater chance of having a baby that weighs too little and may have health problems when born.
  • Sudden Infant Death Syndrome (SIDS) External Link is also linked to the father’s tobacco use.
  • Second-hand smoke exposure during pregnancy can have an impact on a child’s attention, behaviour, and ability to reason and understand.
  • Your baby practices breathing before birth. Second-hand smoke stops these breathing-like movements, which can affect lung development.
  • It is easier for a pregnant woman who smokes to quit if her partner quits.

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What happens to babies who are exposed to second-hand smoke?

  • When your baby breathes second-hand tobacco smoke all day, the effect is the same as smoking two to three cigarettes per day.
  • Second-hand smoke can cause infants to cough and wheeze more, to have more colds, ear and lung infections.
  • They may be hospitalized due to illness in their first year of life.
  • Babies whose mother did not smoke during pregnancy, but smoked after birth are twice as likely to die of SIDS (Sudden Infant Death Syndrome). If both parents smoke, the risk is almost four times higher.

If you, your partner or your caregivers smoke in the home, your child will be more likely to:

  • Develop more colds, coughs, bronchitis and pneumonia than other children.
  • Have lungs that don't work as well.
  • Develop asthma.
  • Develop middle ear infections.
  • Have more allergies.
  • Have certain behaviour problems including hyperactivity and shorter attention spans.
  • Have a decreased ability to reason and understand (cognition) and poorer performance at school.
  • Be the victim of a house fire.
  • Get sick or die from eating cigarette butts (4 butts can kill a baby).
  • Be at risk for the development of cancer and heart disease in adult life.

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If I smoke, can I still breastfeed?

  • If you smoke, breastfeeding is still the best choice for your baby.
  • Breast milk is the best food for your baby - It is easily digested and it protects your baby from many diseases.
  • When breastfeeding, nicotine is passed to the baby through breast milk. As a result, your baby may be cranky, restless and spit up more often from the chemicals that pass through your breast milk. For this reason it is better to breastfeed before having a cigarette and to smoke as few cigarettes as possible.
  • Be aware that smoking may decrease the amount of milk produced and slow down the let-down reflex.
  • Remember that your baby is affected by the second-hand smoke in the air whether you breastfeed or bottlefeed.

There are things you can do to reduce the effect of smoking on breastfeeding:

  • Quit smoking if you can
  • Smoke less. Chemicals in tobacco smoke are passed to your baby through the breast milk as well as by breathing smoke-filled air.
  • Smoke after breastfeeding rather than before.
  • Reduce the amount of time your baby is exposed to second-hand tobacco smoke.

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Where can I get help to quit smoking?

  • In Halton, the The Stop Smoking Clinic offers free personal counselling with a doctor, nurse practitioner or other trained health professional, to help you quit smoking.
  • The Smoke-Free Living  section of this website provides a number of links to information and resources that can help you if you are thinking about quitting smoking.

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