Smoking during pregnancy

When you smoke, harmful chemicals enter your bloodstream and pass through the placenta to your baby. Smoking reduces the oxygen available to your baby and increases the risk of complications including miscarriage, stillbirth, preterm birth, fetal growth restriction, low birth weight, and Sudden Unexplained Death in Infancy (SUDI).

Smoking can affect how the placenta works and is linked to a range of longer-term health problems for children, including respiratory illness, asthma and ear infections. Exposure to second-hand smoke during pregnancy and after birth can also harm babies and children.

Stopping smoking at any stage of pregnancy has benefits for both you and your baby. The earlier you stop, the greater the benefits, but it is never too late to quit.

Support is available. Smoking is an addiction and many people find it difficult to stop without help. Talk with your midwife about local stop-smoking services or visit the Smokefree website. Quitline also provides free support by phone and text.

It is important to keep your home, car and other environments smoke-free and to ask family members and visitors not to smoke around you or your baby.

Vaping (e-cigarettes), pregnancy and breastfeeding

Electronic cigarettes (e-cigarettes or vapes) are battery-operated devices that heat a liquid to create an aerosol that is inhaled.

If you do not smoke, do not start vaping during pregnancy.

Most vaping products contain nicotine. Nicotine is addictive and crosses the placenta, reaching the developing baby. Vaping products may also contain other substances, including flavourings, solvents and trace amounts of metals.

Research suggests that vaping is likely to expose both the pregnant woman or person and baby to fewer harmful chemicals than smoking tobacco. However, vaping is not risk-free. Emerging evidence links vaping during pregnancy with adverse outcomes including fetal growth restriction (small-for-gestational-age babies) and preterm birth.

Recent New Zealand research has raised concerns about nicotine exposure during pregnancy, including possible associations between maternal vaping and Sudden Unexplained Death in Infancy (SUDI). While further research is needed, current evidence supports avoiding nicotine exposure during pregnancy whenever possible.

For women and people who smoke, switching completely from smoking to vaping may reduce exposure to some of the harmful chemicals found in tobacco smoke. However, stopping both smoking and vaping is the safest option during pregnancy.

Evidence on vaping during breastfeeding is still evolving. Nicotine can pass into breast milk, and avoiding vaping is recommended where possible. Breastfeeding remains the best source of nutrition for babies, and parents who vape are encouraged to seek support to reduce or stop vaping and to avoid vaping around their baby.

Support and Further Information

• Talk with your midwife about smoking and vaping cessation support available in your area.
• Visit Smokefree New Zealand: https://www.smokefree.org.nz/help-advice/stop-smoking-services
• Contact Quitline: https://quit.org.nz/reasons-to-quit/smoking-and-pregnancy

References

Key New Zealand Evidence

1. Mitchell EA, Cowan S, Taylor BJ. Maternal Smoking, Vaping and Infant Sleep Practices in Sudden Unexpected Death in Infancy: A New Zealand Case Series. Journal of Paediatrics and Child Health. 2026;62(7):1134-1140. doi:10.1111/jpc.70352.
2. Mitchell EA, Cowan S, Taylor BJ. The Case for a Pregnancy-Specific Nicotine Policy. Acta Paediatrica. Published online July 14, 2026. doi:10.1111/apa.70687.

International and National Guidance

3. World Health Organization. Tobacco and Pregnancy. World Health Organization.
4. Health New Zealand | Te Whatu Ora. Vaping and Smoking in Pregnancy. Health New Zealand | Te Whatu Ora.
5. NSW Health. Smoking and Vaping in Pregnancy. Updated 2026.

Supporting Evidence

6. McDonnell BP, et al. Vaping During Pregnancy: A Systematic Review of Health Outcomes. BMC Pregnancy and Childbirth. 2024.
7. Gould GS, Havard A, Lim LL, Kumar R, et al. Exposure to Tobacco, Environmental Tobacco Smoke and Nicotine in Pregnancy: A Pragmatic Overview of Reviews of Maternal and Child Outcomes, Effectiveness of Interventions and Barriers and Facilitators to Quitting. International Journal of Environmental Research and Public Health. 2020;17(6):2034.

Recreational drugs during pregnancy

Using recreational drugs can cause complications during pregnancy and serious problems in the developing fetus and the newborn baby. For pregnant women, injecting recreational drugs increases the risk of infections that can affect or be transmitted to the fetus. These infections include hepatitis and sexually transmitted diseases (including HIV).

Drugs such as methamphetamine can cause significant harm to your baby, including brain damage and birth defects. Other drugs such as heroin may cause your baby to be born drug dependent and suffer from withdrawal symptoms. Drug-dependent babies need expert care following birth.

If you are using drugs, talk to your midwife or GP. They are there to support you, not judge you and they will be able to refer you to a local service for further help and support. The Alcohol Drug Helpline provides free, confidential information, help and support:

• 0800 787 797 (24 hours a day)
• free text 8681