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Smoking and pregnancy

Published: December 2015

Please note that this information will be updated every 3 years after publication.

Updated: October 2020

This information is about the effects of smoking during pregnancy and support available to help you to stop.

It may also be helpful if you are the partner, relative or friend of someone who is in this situation.

This information is for you if you smoke and are either already pregnant or thinking about having a baby. It is also for you if you are exposed to tobacco smoke at home. Partners and relatives of women who smoke may also find it helpful.

Many women find it difficult to stop smoking but it is one of the most important things you can do to improve your baby’s health, growth and development. It is also the single most important thing that you can do to improve your own long-term health.

This information tells you about the effect of smoking on you and your baby. It also tells you about the help and support that you will be offered to stop smoking. It’s never too late to stop smoking and your healthcare team will be supportive throughout your pregnancy.

The information here aims to help you better understand your health and your options for treatment and care. Your healthcare team is there to support you in making decisions that are right for you. They can help by discussing your situation with you and answering your questions.

Within this information, we may use the terms ‘woman’ and ‘women’. However, it is not only people who identify as women who may want to access this information. Your care should be personalised, inclusive and sensitive to your needs, whatever your gender identity.

A glossary of medical terms is available at A-Z of medical terms.

Key points
  • Smoking in pregnancy is harmful to you and your baby.
  • Passive smoking can also harm you and your baby.
  • A baby that is small due to smoking is not a healthy baby.
  • If you smoke, the best thing you can do is stop. Stopping at any time in pregnancy will help, though the sooner the better.
  • You should stop completely (rather than just cut down), ideally before getting pregnant.
  • You and your partner will be offered help, advice and support to stop smoking.
  • You will be offered a carbon monoxide (CO) test early in your pregnancy.
  • Nicotine replacement therapy (NRT) is safe to use in pregnancy.

Just as smoking is bad for you, babies in the womb can be harmed by tobacco smoke because it reduces the amount of oxygen and nutrients that pass through the placenta from you to your baby.

Smoking when you are pregnant increases your risk of:

  • miscarriage
  • ectopic pregnancy (a pregnancy growing outside the womb)
  • your baby dying in the womb (stillbirth) or shortly after birth – one-third of all deaths in the womb or shortly after birth are thought to be caused by smoking
  • your baby being born with abnormalities – face defects, such as cleft lip and palate, are more common because smoking affects the way your baby develops
  • your baby’s growth and health being affected – the more you smoke, the less healthy your baby will be, and a baby that is small due to smoking is more likely to have health problems when young and also later in life
  • bleeding during the last months of pregnancy, which is known as an abruption (when the placenta comes away from the wall of the womb) – this could be life threatening for you and your baby
  • premature birth, when you have your baby before 37 weeks of pregnancy.

Babies and children whose mothers smoke during pregnancy are also at greater risk of:

  • sudden and unexplained death, known as sudden infant death syndrome (SIDS) – as well as happening to newborn babies, this can also happen to infants over 12 months: the risk is greater if you or your partner continue to smoke after she or he is born, particularly if you share a bed with your baby at night
  • asthma, chest and ear infections, and pneumonia
  • behaviour problems such as ADHD (attention deficit hyperactivity disorder)
  • performing poorly at school.

Stopping smoking reduces all the risks described above.

Yes. From your first antenatal appointment, your midwife will ask whether you or any other member of the household smokes. This is important so that you and your family can be given support and help to stop smoking as early as possible. You will be asked how often you smoke and how much tobacco you smoke a day.

You will be given information about how smoking and passive smoking harms you and your baby.

There is no safe level of smoking, either for you or your baby. The earlier you stop smoking, the greater the benefit to you and your baby, but it is important to know that stopping at any time during pregnancy is beneficial to some extent.

Reducing the number of cigarettes you smoke is a positive step, although there is no evidence that this is better for your baby. Therefore, both you and your partner will be advised to stop completely – not just cut down. To help you with this, you should be referred to services that will help you both to stop smoking (see Further Information below).

Yes. If you are exposed to other people’s tobacco smoke, it is known as passive smoking. Babies in the womb exposed to smoke in this way have a higher than normal risk of:

  • being stillborn or dying soon after birth
  • being born early
  • their growth and health being affected.

Ask smokers to support you and your baby by smoking outside and not near you. This includes in the car. Also, try to keep away from smoky places and people who are smoking.

Carbon monoxide (CO) levels are higher in women who smoke and in passive smokers than in women who don’t. CO is a poisonous gas that restricts the amount of oxygen getting to your baby.

At your first antenatal appointment your midwife will ask you to do a breath test, which will measure your level of exposure to CO. This will help your midwife measure your exposure to tobacco smoke.

All pregnant women are advised to have the test whether they smoke or not as levels may also be high if you have faulty gas appliances at home. CO poisoning can be fatal. If you don’t smoke and you are not exposed to tobacco smoke but your levels are high, you should contact the free Health and Safety Executive Gas Safety Advice Line on 0800 300 363.

CO levels may also be raised if you are exposed to high levels of pollution or if you have a medical condition called lactose intolerance.

You may be aware of the risks and want to stop smoking but find it really difficult to do so. If you smoke or have recently stopped smoking (within the last 2 weeks), you should be referred to a specialist midwife or stop smoking adviser for support.

You will be given their contact numbers but they will also phone you and offer support. Typically, the stop smoking service team will offer you one-to-one appointments, and will also suggest ways to help you cope with the cravings and withdrawal symptoms that you may have once you stop smoking. The length of time that you will need support will depend on you and your circumstances, but typically it will be a 12-week programme to help you through the initial period.

It may be difficult to begin with, but 4 out of 5 women who manage to stop smoking for 28 days do so for good. Your midwife will ask how you are getting on at each appointment and write in your notes whether you are smoking or not.

Your partner or other close family members and friends who smoke can support you by stopping too. This will improve the chances of you successfully giving up. They should be offered help and encouragement to stop too.

The midwives and doctors looking after you will be supportive. You can also get help from your GP, the NHS Choices website ( and the NHS Smokefree website (, or you can phone the NHS Smoking Helpline on 0300 123 1044.

Nicotine replacement therapies (NRT), such as patches, chewing gum, lozenges or mouth sprays, deliver clean forms of nicotine and are safe and effective aids for people who want to stop smoking.

It is safe to use NRT in pregnancy. Using NRT is safer than smoking because it doesn’t contain poisons such as tar or CO, but does provide you with some nicotine to help you manage any withdrawal cravings once you have stopped smoking.

Your stop smoking adviser will be able to discuss the options with you in more detail, and advise how you can obtain these products for free during your pregnancy.

Some drugs prescribed to help smokers stop are not safe to use during pregnancy or when breastfeeding. Check with your GP or your stop smoking adviser if you want to know more about this.

Little research has been conducted into the safety of e-cigarettes in pregnancy. Using e-cigarettes is not entirely risk-free, but research on their use among the general adult populations shows that vaping is substantially less harmful than smoking tobacco and likely to be significantly less harmful to a pregnant woman and her baby than cigarettes.

If you're pregnant, licensed NRT products such as patches and gum are the recommended option to help you stop smoking. But if you find using an e-cigarette helpful for quitting and staying smokefree, it's likely to be safer for you and your baby than continuing to smoke.

You can find further information here:

Evidence shows that using both e-cigarettes and smoking (dual using) does not confer any health benefit over using just cigarettes. If you are using both e-cigarettes and smoking you should be supported to stop smoking. There is further information about services that can help at the end of this information.

  • Women who smoke take longer to get pregnant. Smoking also affects the man’s sperm count. Stopping smoking improves sperm count and quality.
  • If you stop smoking, your breast milk will be of better quality and you will produce more of it.

Further information

NHS Smokefree

NHS information on smoking and pregnancy

How to contact a stop smoking adviser

Your GP can refer you, or you can phone your local NHS Stop Smoking Service to make an appointment with an adviser:

RCOG patient information 

NICE guidance

Shared Decision Making

If you are asked to make a choice, you may have lots of questions that you want to ask. You may also want to talk over your options with your family or friends. It can help to write a list of the questions you want answered and take it to your appointment.

Ask 3 Questions

To begin with, try to make sure you get the answers to 3 key questions, if you are asked to make a choice about your healthcare:

  1. What are my options?
  2. What are the pros and cons of each option for me?
  3. How do I get support to help me make a decision that is right for me?

*Ask 3 Questions is based on Shepherd et al. Three questions that patients can ask to improve the quality of information physicians give about treatment options: A cross-over trial. Patient Education and Counselling, 2011;84:379-85 

Sources and acknowledgements

This information has been developed by the RCOG Patient Information Committee. It is based on the NICE 2010 Public Health Guidance Smoking: Stopping in Pregnancy and after Childbirth and the NICE 2008 Clinical Guideline Antenatal Care for Uncomplicated Pregnancies. The guideline contains a full list of the sources of evidence we have used.

This information was reviewed before publication by women attending clinics in Newcastle-upon-Tyne, by the RCOG Women’s Network and by the RCOG Women’s Voices Involvement Panel.