Smoking in Pregnancy: A Danger to Mother and Baby
Published: 02 July 2018
Published: 02 July 2018
Smoking in pregnancy poses a significant health problem for both mother and baby.
Many women who smoke will quit by themselves before becoming pregnant and others will stop once their pregnancy is confirmed. For some women, however, considerable help is needed to successfully stop smoking (NCSCT 2018).
The research evidence is clear: cigarettes contain multiple harmful substances, and women who smoke during pregnancy are more likely to have babies with birth defects than non-smokers.
As smoking in pregnancy adversely affects so many different aspects of health, it remains one of the greatest factors that could potentially improve birth outcomes (NIRH 2017).
It’s well known that smoking can impair fertility (Your Fertility 2021), and in addition to the general risks of smoking, pregnant women also face additional pregnancy-related health risks including:
(DoH 2021; QLD Health 2021)
Smoking while pregnant is well-known to be harmful to the growing fetus, with an increased risk of miscarriage, IVF failure, intrauterine growth restriction, premature birth and birth defects (DoH 2021; Quit Victoria 2018).
Nicotine, together with the multiple carcinogenic pollutants found in cigarettes, is detrimental to healthy fetal development. It’s generally agreed that unless further research proves otherwise, public health information should make women aware of these potential risks and provide practical help and encouragement to quit smoking early in pregnancy, and ideally prior to conception.
As nicotine addiction is the factor that stops many women from giving up smoking during pregnancy, the use of nicotine replacement therapy (NRT) has been suggested as a lower risk to the fetus. However, the safety of NRT has not yet been well documented and many researchers have conflicting opinions about its potential to harm the fetus.
Wickström (2007) suggests that this is because the causative agents for the harmful effects of smoking have been difficult to determine as cigarette smoke contains thousands of biologically active compounds. Some of these substances are well known to be fetal toxins, for example, carbon monoxide and nicotine. The effecst of many other potential toxins have yet to be effectively researched.
In theory, nicotine replacement should be safer than smoking, but as several animal studies have shown, the total dose of nicotine that the fetus is exposed to is a significant factor for brain development. Since conventional doses of NRT may be less effective in pregnancy, the higher doses of nicotine needed may exceed the threshold for alterations in brain development and cause fetal harm.
That said, there is a general view that NRT during pregnancy is safer than smoking. At the same time, it’s widely acknowledged that total abstinence from all forms of nicotine should be advised to pregnant women from pre-conception through to birth.
The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (2020) recommends that non-pharmacological interventions be used as first-line therapy, however, NRT may be considered in patients who cannot achieve abstinence with non-pharmacological interventions alone.
In these cases, NRT should be used 'at the most effective dose for the shortest duration possible ' in order to reduce fetal exposure to nicotine (RANZCOG 2020).
Although pregnancy is often a strong motivator for smoking cessation, many women continue to smoke and more effective strategies to help them become non-smokers are urgently needed.
It’s now widely accepted that any contact with a pregnant woman from preconception through to postnatal visits provide an opportunity to give advice on smoking cessation, but many midwives remain unclear on what exactly this advice should be.
In the UK, the National Institute of Clinical Excellence (NICE 2010) suggests that practitioners should follow the ask, advise and act sequence to help pregnant patientd become non-smokers:
Although these guidelines are clear about the need to help pregnant patients stop smoking, it’s also clear that practitioners lack confidence and training on how to communicate this message in a way that actually achieves behavioural change.
Similar research carried out by Longman et al. (2018) explored the enablers and barriers to implementation of the Australian smoking cessation in pregnancy guidelines. These guidelines suggest that practitioners follow the 5 A’s of cessation:
Again, barriers to success include knowledge and skills gaps, reluctance to engage in ‘difficult conversations’, as well as perceiving smoking as a social activity.
Finding innovative and effective ways to reduce smoking in pregnancy remains a priority. To date, there is still relatively little evidence on the efficacy of smoking cessation interventions before or after pregnancy, or on preventing relapse after quitting during pregnancy (NIRH 2017).
Smoking remains one of the few modifiable risk factors in pregnancy, yet it continues to be a worldwide public health concern.
From the patient’s point of view, this is an invisible problem and as long as smoking continues to be viewed as an acceptable social activity rather than as an addiction, it’s unlikely that significant progress will be made.