Reviewed April 2014, next review April 2017

woman's hands breaking a cigarette

Smoking and pregnancy

Giving up smoking during pregnancy will not only boost your baby’s development, but help improve their health right into adulthood.

When you become pregnant you have a more important reason to give up smoking than ever. Giving up smoking is tough whenever you choose to do it but there is support out there for you to help boost your chances of quitting.

If you don't smoke, but are exposed to cigarette smoke because your partner, or someone else you know smokes, you can read about the risks of second-hand smoke. This may help you to persuade your partner to give up, or to make sure you and your baby are not exposed.

Try our cost calculator below: see how much money you could save if you stopped smoking, and what you could buy instead:

Smoking calculator

How many cigarettes do you smoke per day?

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Effects of smoking in pregnancy

Research shows that smoking in pregnancy is directly linked to problems including:

The good news is that it’s never too late to benefit from quitting smoking. In fact, because the most harmful effects of smoking during pregnancy occurs in the second and third trimester, giving up smoking in the first three months of pregnancy reduces your risk of having a low birth weight baby to that of a non smoker.

However, giving up at any time during pregnancy will help give your baby the best start in life.

Heather, one-year smoke free

'I used to smoke 30-40 cigarettes a day. which not only had a detrimental affect on my health but it burnt a great big hole in my pocket! When I found out I was pregnant, I immediately quit.

'If I carried on smoking it could have serious side effects. I figured, what’s the point in me carrying on?'

Read more detail about the effects of smoking in pregnancy, or read our questions about smoking and pregnancy.

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Talking to your midwife about smoking in pregnancy

Your midwife will ask lots of questions about your lifestyle, including whether you smoke or have recently quit, or if someone in your household smokes. Smoking in pregnancy is something midwives have to discuss with all the women they deal with, so don’t feel that you are being singled out.

If you smoke, or have quit within the past two weeks, your midwife will refer you to a Pregnancy Stop Smoking advisor at your local branch of the NHS Stop Smoking Services

Carbon monoxide breath testing

Your midwife may offer you a carbon monoxide (CO) breath test. This indicates you and your baby’s level of exposure to this harmful gas. See our effects of smoke on pregnancy page for more information on why carbon monoxide is so dangerous.

To measure the level of carbon monoxide in your breath you blow into a machine. Some machines can also calculate the level of CO getting to your baby. The higher your level of exposure to CO, the higher your CO reading will be.

The reading is given in COppm, which is the number of CO molecules in a million parts of air. Women with a reading of 4ppm or higher may be referred to stop smoking services.

Download a leaflet about testing your breath for carbon monoxide here.

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Silagy C et al, Nicotine replacement therapy for smoking cessation, Cochrane Database Syst Rev 2004; (3):CD000146

Kharrazi M et al, Environmental tobaccosmoke and pregnancy outcome, Epidemiology 2004; 15(6):660-70

MacArthur C and Knox EG, Smoking in pregnancy: effects of stopping at different stages, Br J Obstet Gynaecol 1988; 95(6):551-5

NHS Direct, Smoking (quitting), Cardiff NHS Direct Wales, 2010. Also available at: (accessed 1 April 2014)

McCowan LM et al, Spontaneous preterm birth and small for gestational age infants in women who stop smoking early in pregnancy: prospective cohort study, Br Med J; 338:b1081

National Institute for Health and Care Excellence, Quitting smoking in pregnancy and following childbirth, public health guidance 26, Lodnon NICE, 2010

Lowry C, Scammel K, Smoking cessation in pregnancy: a call to action, London Ash, 2013: (accessed 1 April 2014)



In this section

Diet and nutrition
Managing your weight




Mental health

Healthy working pregnancy

Labour and birth


On this page

Why quit smoking in pregnancy?

Talking to your midwife

More about smoking

Effects of smoking

Quitting smoking

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