Various effects of smoking in pregnancy are described:
- increased risk of premature delivery
- associated with intrauterine growth retardation - infants born to mothers who smoke are, on average, 170 g lighter; there is x2 risk of having an infant with a birthweight of under 2500g compared with non-smoking mothers
- perinatal deaths are more common in infants born to mothers who smoke
- spontaneous abortions are more common in mothers who smoke (1)
The risk of pre-eclampsia is LOWER for women who smoke than for non-smoking mothers.
NICE state that (2):
Smoking in pregnancy
- at the first contact with the woman, discuss her smoking status, provide information about the risks of smoking to the unborn child and the hazards of exposure to secondhand smoke. Address any concerns she and her partner or family may have about stopping smoking
- discuss the risks and benefits of nicotine replacement therapy (NRT) with pregnant women who smoke, particularly those who do not wish to accept the offer of help from the NHS Stop Smoking Service. If a woman expresses a clear wish to receive NRT, use professional judgement when deciding whether to offer a prescription
NICE guidance with respect to smoking cessation in pregnancy states (3):
- there should be provision of routine carbon monoxide testing at the first antenatal appointment and at the 36-week appointment to assess the pregnant woman or pregnant person's exposure to tobacco smoke. Provision of carbon monoxide testing at all other antenatal appointments if they:
- smoke or
- are quitting or
- used to smoke or
- tested with 4 parts per million (ppm) or above at the first antenatal appointment
- there should be provision of an opt-out referral to receive stop-smoking support during pregnancy for those who:
- say they smoke or have stopped smoking in the past 2 weeks or
- have a carbon monoxide reading of 4 ppm or above or
- have previously been provided with an opt-out referral but have not yet engaged with stop-smoking support
Reference:
- Roberta B (1999). NEJM, 340, 333.
- NICE (March 2016). Antenatal care for uncomplicated pregnancies
- NICE (February 2025). Tobacco: preventing uptake, promoting quitting and treating dependence