Pregnancy

Despite concerted efforts by researchers and health care professionals, maternal smoking during pregnancy remains a serious public health problem. Approximately 20% - 30% of pregnant women use tobacco during pregnancy. Many of these women quit during pregnancy and another proportion reduce their tobacco use.

On this page:

• Impact on Health
• Pre- and Postnatal Smoking Issues

Impact on Health

Smoking in pregnancy results in serious risks for both the woman and the fetus. Cigarette smoking by pregnant girls and women has been shown to increase risks of complications in pregnancy and to cause serious adverse fetal outcomes including low birth weight, still births, spontaneous abortions, decreased fetal growth, premature births, placental abruption, and sudden infant death syndrome (SIDS). Other reproduction related effects of smoking include lower estrogen levels leading to early menopause and links to infertility.

Quitting smoking during pregnancy has considerable positive health impact for both women and fetuses, and reduces health problems for children born of mothers who smoke.

• Quit Smoking Telephone Counselling Protocol for Pregnant and Postpartum Women

Pre- and Postnatal Smoking Issues

How Are Unborn Babies Affected?

• Smoking is known to have an effect on babies before they are born. Nicotine, carbon monoxide and other chemicals in tobacco smoke are passed on to the baby through the placenta.^{Footnote 1} 
• Nicotine increases a baby's heart rate and breathing movements. Some of the chemicals passed on through the mother's blood are known to cause cancer.^{Footnote 2}
• During pregnancy, smokers have a greater risk of miscarriages. During the birth, they are more likely to have complications.^{Footnote 3} The chances of a baby's dying at birth or shortly thereafter are increased if the mother has smoked during pregnancy.^{Footnote 3}
• Babies of women who smoked or were exposed to second-hand tobacco smoke during pregnancy are, on average, smaller at birth than babies of non-smoking mothers. Smoking mothers give birth to infants who weigh about 150 grams less at term than non-smokers.^{Footnote 1},^{Footnote 3} Babies born with a lower-than-average birth weight are more likely to get infections and have other health problems.^{Footnote 4}
• A clear relationship exists between the number of cigarettes smoked during pregnancy and a slowdown in the growth of the fetus. ^{Footnote 1},^{Footnote 3}  These babies are more prone to perinatal complications, illnesses and death.

Side-effects: Newborns

• Nursing mothers who smoke can pass along harmful chemicals from cigarettes to their babies in breast milk. But it is important to note that a smoker's breast milk is still better than formula, in regards to a baby's development.
• More than 18% of all deaths from Sudden Infant Death Syndrome (SIDS) are due to maternal tobacco use.^{Footnote 9} 
• Even in later years, children of mothers who smoked during pregnancy tend to be slightly shorter than other children and have more difficulty with reading, mathematics and related skills.^{Footnote 5} 

Parental Smoking

• It has not yet been determined if male smoking damages the sperm, thereby contributing to low birthrates and higher infant mortality rates.^{Footnote 5},^{Footnote 6} 
• Babies of smokers are more likely to suffer from asthma and other respiratory infections than those of non-smokers.^{Footnote 10} 
• Children exposed to tobacco smoke are more likely to cough during the night, probably due to the long-term effect of breathing in tobacco smoke.^{Footnote 11} 
• The long-term effects of parental smoking around children may be impaired learning, slower growth and changes in behaviour.^{Footnote 3},^{Footnote 12}