We all know that smoking is bad for your health, especially during pregnancy when it affects your baby’s health as the nicotine, carbon monoxide, and other toxins pass from our lungs through the placenta. But even after the birth, if you or your partner smoke (or people you socialise with do), your new baby will still be at risk from second and third-hand smoke. We look at some of the risks you might not be aware of in this article.

Smoking in pregnancy

Women who smoke during pregnancy or are regularly exposed to second-hand smoke (from those smoking around you) are more at risk of 

  • Miscarriage (approx. 5000 each year in the UK due to smoking).
  • Ectopic pregnancy (occurs when the fetus grows outside of the womb).
  • Complications during pregnancy and labour include bleeding, placental abruption (when the placenta detaches from the wall of the womb), waters breaking prematurely and eclampsia. These can be life-threatening to mum and baby.
  • Premature birth (approximately 2,200 each year in the UK due to smoking).

Your baby is more at risk of 

  • Low birth weight. On average, babies are 250g lighter if their parents smoke. Being underweight can lead to additional health issues, and extended hospital stays after birth.
  • Birth abnormalities include heart defects, cleft lip and palate, or shorter and missing limbs.
  • Stillbirth or early neonatal death. Smoking in pregnancy is the number one risk factor for stillbirth and SIDS.
  • Sudden Infant Death Syndrome (SIDS), previously known as cot death. Approximately 1 in 3 babies’ lives could be saved from SIDS if a parent didn’t smoke.
  • Asthma, chest and ear infections and pneumonia
  • Colic
  • Behavioural issues, including Attention Deficit Hyperactivity Disorder (ADHD)

Antenatal care

Smoking during pregnancy results in more than 1,000 infant deaths annually. This is one of the main reasons midwives ask if you or anyone in your household smokes and advise you on how to quit. Cutting down is still not safe for your baby, but stopping during your pregnancy can reduce the risk factors mentioned above.

Whether you smoke or not, your midwife will ask you to do a carbon monoxide breath test at your first antenatal appointment. If the carbon monoxide reading is high, it can impact how much oxygen and nutrients pass through your placenta to your baby.

If your carbon monoxide reading is high and no one in your household smokes, your midwife will discuss some of the reasons for this. It could include considering what fuel-burning appliances you have at home, such as a gas boiler or wood burner, and traffic emissions you may be exposed to. 

You can contact the Gas Emergency Line on 0800 111 999 for safety advice.

Smoking around your baby

Second-hand smoke contains more than 4,000 irritants, toxins and cancer-causing substances. In children, it can also cause asthma, serious respiratory infections such as bronchitis and pneumonia, meningitis and middle ear infections that can cause hearing loss. In fact, every year in the UK, 17,000 children under five are admitted to hospitals due to second-hand smoke. 

Things to consider

  1. Even if you only smoke in one room, second-hand smoke can spread throughout the house within minutes – including up to your baby’s room.
  2. Smoke can stay in the air for two to three hours after you’ve finished a cigarette – even if you opened the window.
  3. Did you know that cars are often found to have concentrations of toxins up to 11 times higher than you used to find the average smoky pub? Since 2015 it has been illegal to smoke in a vehicle with anyone under 18. Both the driver and smoker can be fined £50 if caught.

If you or anyone else smokes, ask them to smoke outside, with the door shut – and never in a car, your baby will use.

Babies in smoking households are more at risk of SIDS. If you or your partner smokes, you must never co-sleep with your baby (on a bed or sofa), which further increases the risk of SIDS. Instead, always put them down in their cot or Moses basket when you both feel sleepy. The advice is the same if you have drunk alcohol or are taking any medication that causes drowsiness.

Breastfeeding and smoking

As a new mum, if you’re a smoker or passive smoker due to someone in your household smoking, your baby can still ingest toxins from you. This is not just from your breath; it’s also in your breast milk if you’re breastfeeding.

It is essential to recognise that whether you smoke or not, breastfeeding still offers the most health benefits for your baby. 

However, there are some things to consider that may encourage you to stop smoking if you are breastfeeding: 

  • Breastmilk can taste like tobacco after smoking. 
  • Nicotine and other harmful chemicals pass into your breast milk. The levels peak approximately 30-60 minutes after you’ve finished smoking. The half-life of nicotine in breast milk is about 2 hours. In other words, it takes this long for the level to halve. 
  • Smoking and passive smoking may lower how much milk you produce, impacting your supply to the baby. This may be one of the reasons women who smoke breastfeed for a shorter time. 
  • It can affect your baby’s sleep cycle, meaning they sleep for shorter periods with less time spent in active and quiet sleep. The higher the nicotine level, the higher the impact on the baby’s sleep.

Third-hand smoke

Third-hand smoke is the chemical residue left after someone has smoked on clothes, toys, bedding, furniture, vehicles, and even dust. For example, a baby can breathe in harmful toxins from a smoker or passive smoker’s hair and clothes. Alternatively, toddlers may ingest toxic chemicals by putting toys and other objects into their mouths.

Did you know that the homes of former smokers remain polluted with third-hand smoke for up to six months after the residents quit smoking? Routine cleaning or using an air freshener won’t get rid of third-hand smoke. It’s essential to raise awareness, so smokers know the risks and are more careful around babies and pregnant women.

If someone you live with is a smoker, create a smoke-free environment for your baby. This can be done by ensuring they smoke outside and away from the house and remove their jacket before entering the house.

The best ways to protect your baby

  • Don’t allow anyone to smoke inside your home or car.
  • Make sure to sit in non-smoking areas when you’re out.
  • Let your friends and family know about the dangers of second and third-hand smoke.
  • Avoid letting people who have recently smoked a cigarette hold your baby.
  • Stop smoking before the baby arrives, ideally as soon as you find out you’re pregnant. Include those in your household or caring for your baby.1

Quit smoking support

If you or your partner want to quit smoking, plenty of free support is available to help you. The support will be personalised to suit your needs. 

During pregnancy, your midwife can refer you to the stop-smoking team or ask your GP or health visitor; if you prefer, there are also many online resources on the NHS Smokefree website, or you can call the NHS Smoking Helpline on 0300 123 1044. 

Nicotine patches, chewing gum and mouth sprays are generally considered safe to use in pregnancy if it helps you quit. The stop-smoking support team can recommend the most suitable products and doses. However, there is very little research into how safe vaping is during pregnancy, so approach this option cautiously with advice from your stop-smoking support team. You can also discuss what other 2treatments and replacement therapies are safe.

Content Disclaimer

The information contained above is provided for information purposes only. The contents of this article are not intended to amount to advice, and you should not rely on any of the contents of this article. Professional advice should be obtained before taking or refraining from taking any action as a result of the contents of this article. New Life Classes disclaims all liability and responsibility arising from any reliance placed on any of the contents of this article.


Department of Health and Social Care (2015) Smoking in vehicles

Jacob P 3rd, Benowitz NL, Destaillats H, Gundel L, Hang B, Martins-Green M, Matt GE, Quintana PJ, Samet JM, Schick SF, Talbot P, Aquilina NJ, Hovell MF, Mao JH, Whitehead TP. Third-hand Smoke: New Evidence, Challenges, and Future Directions. Chem Res Toxicol. 2017 Jan 17;30(1):270-294. doi: 10.1021/acs.chemrestox.6b00343. Epub 2016 Dec 21. PMID: 28001376; PMCID: PMC5501723.

Mennella JA, Yourshaw LM, Morgan LK. Breastfeeding and smoking: short-term effects on infant feeding and sleep. Pediatrics. 2007 Sep;120(3):497-502. doi: 10.1542/peds.2007-0488. PMID: 17766521; PMCID: PMC2277470.

NHS (2018) Breastfeeding and smoking

NHS (2022) Passive smoking

NHS (2019) Stop smoking in pregnancy

NHS Digital: Statistics on women’s smoking status at time of delivery: England, Quarter 4, 2021-22. Published July 2022 

NICE guideline [NG209] Tobacco: preventing uptake, promoting quitting and treating dependence Published November 2021. 

NICE public health guideline [PH26] Smoking: stopping in pregnancy and after childbirth. Published June 2010. 

Primo CC, Ruela PB, Brotto LD, Garcia TR, Lima Ede F. Effects of maternal nicotine on breastfeeding infants. Rev Paul Pediatr. 2013 Sep;31(3):392-7. doi: 10.1590/S0103-05822013000300018. PMID: 24142324; PMCID: PMC4182966.

The Royal College of Obstetricians and Gynaecologists (2015) Smoking and pregnancy patient information leaflet