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24 November, 2009

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Pregnancy and smoking

Australian data indicates that approximately 20 per cent of women smoke during pregnancy, although this rate appears to be declining. A woman who smokes while pregnant is at increased risk of experiencing a wide range of problems including ectopic pregnancy, miscarriage and premature labour.

Women who smoke are up to three times more likely to give birth to a low weight baby compared to non-smokers. Low birth weight babies are more vulnerable to infection and other health problems, such as breathing difficulties.

The more cigarettes smoked during pregnancy, the greater the risk of complications.

Pregnancy complications
Some of the pregnancy complications more commonly experienced by women who smoke include:

Ectopic pregnancy (pregnancy outside the uterus – usually in the fallopian tube)
Foetal death (death of the baby in the uterus)
Spontaneous abortion (miscarriage)
Problems with the placenta, including early detachment from the uterine wall and blocking the cervical opening (placenta previa)
Premature rupture of the membranes
Premature labour.

Effects on the foetus
Every time a pregnant woman smokes a cigarette, her unborn baby is deprived of oxygen and exposed to the same cocktail of chemicals, including chemicals which cause cancer.

Some of the many damaging effects of cigarette smoke on the foetus include:

Reduced oxygen supply due to carbon monoxide and nicotine
Retarded growth and development
Increased risk of cleft lip and cleft palate
Increased heart rate and disruption of the baby’s breathing movements in the womb due to the effects of nicotine.

Problems at birth
Some of the problems caused by maternal smoking include:

Increased risk of premature birth.
Increased risk of miscarriage and infant death.
Lower birth weight - on average, about 250g less than normal.
Twice the risk of sudden infant death syndrome (SIDS).

Problems with breast feeding
Over two thirds of female smokers who quit during pregnancy resume smoking once their babies are born. Some of the problems caused by maternal smoking while breastfeeding can include:

The chemicals in cigarettes can pass from the mother to the baby via breast milk.
Smoking reduces the amount of vitamin C in breast milk.
Smoking can reduce milk production.

Problems for the child in later life
Smoking during pregnancy can impair a child’s health for years to come. Health effects may include:

Decreased lung function
Higher incidence of asthma
Increased risk of developing behavioural problems, such as antisocial behaviour.

See your doctor if you need help to quit
Ideally, a pregnant woman should stop smoking. However, at most only one in three female smokers quit when pregnancy is planned or confirmed. If you need help, see your health professional for information and advice, or call the Quitline on 137 848.

If you are finding it tough to stop smoking, don’t despair. There is evidence to suggest that stopping smoking in the fourth month of pregnancy can reduce some of the risks, such as low birth weight.

Nicotine replacement therapy should be monitored
The use of nicotine replacement therapy (such as patches, gum, inhaler and lozenges) during pregnancy hasn’t been adequately researched, so it is unknown what effect these quitting aids may have on the baby. Therefore, it is recommended that pregnant women should consult their doctor before considering using nicotine replacement therapies. Pregnant women should also seek assistance from the Quitline and their health professional for alternative quitting methods.

Where to get help

Your doctor
Obstetrician
Quitline Tel. 137 848

Things to remember

A woman who smokes while pregnant is at increased risk of experiencing a wide range of problems including ectopic pregnancy, miscarriage and premature labour.
Babies whose mothers smoke during pregnancy are at a higher risk of having a low birth weight.
Low birth weight is a risk factor for health problems including infections and breathing difficulties.

You might also be interested in:
Asthma and pregnancy.
Pregnancy - signs and symptoms.
Pregnancy - week by week.
Pregnancy and diet.
Pregnancy and travel.

Want to know more?
Go to More information for support groups, related links and references.

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