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Smoking cessation in pregnancy

Rates of people smoking in pregnancy have not decreased over the past decade, despite the number of smokers in the general population dropping from 30% to 20%.1 As this is a cause for concern, all healthcare professionals need to know how to offer tailored support to pregnant women who smoke. This article addresses the key issues and action points that can be taken during pregnancy.
The risks of smoking in pregnancy are well established. Smoking amongst pregnant women leads to an increased risk of spontaneous abortion, haemorrhage during pregnancy, low birth weight, premature birth, stillbirth and sudden infant death syndrome (SIDS). Babies born prematurely are at increased risk of short- and long-term health complications, including respiratory problems.2

Who smokes in pregnancy?
The Infant Feeding Survey (IFS)3 conducted every five years is the official source of information on smoking rates in pregnancy. The most recent results showed that:

  •     Mothers in routine and manual occupations were four times more likely than those in managerial and professional occupations to have smoked throughout their pregnancy.
  •     Younger mothers are more likely to smoke. Mothers under the age of 20 are five times more likely than those aged 35 or over to have smoked throughout their pregnancy.
  •     In 2005, a third of mothers in England (32%) smoked in the 12 months before or during their pregnancy.
  •     One in six mothers (17%) reported that they continued to smoke throughout their pregnancy.

The IFS's more positive findings showed that many women do give up smoking during pregnancy. Of the mothers who reported that they had smoked sometime in the 12 months before or during pregnancy, half gave up at some point before birth.

Pre-conceptual advice
First pregnancies were shown to provide a good opportunity for giving advice on quitting smoking. In a primary care setting, the benefits of a smoke-free pregnancy could be explained opportunistically during routine family planning appointments. Pre-conceptual advice is often sought by women because of their desire to have a healthy baby. If they are current smokers, provide information on the benefits of stopping smoking, for example:

  •     Cigarette smoking makes it harder to conceive, irrespective of which partner smokes.
  •     Smoking in men is linked to reduced sperm count, less mobile sperm and higher incidence of impotence.
  •     Smoking is linked with hormonal changes in women that reduce the likelihood of conception.

Barriers to quitting
As you will have observed, some women may decide to continue smoking and be resistant to any advice you provide to quit. The most common reasons are:4

  •     Nicotine addiction.
  •     The belief in positive benefits, for example having a smaller baby and easier delivery.
  •     Having previously smoked during pregnancy.
  •     Having family or friends who smoked in pregnancy with no perceived effects.
  •     Lack of knowledge about the risks of smoking in pregnancy.
  •     Lack of knowledge about the NHS Stop Smoking services.
  •     Lack of knowledge about the use of nicotine replacement therapy.

What helps pregnant women to stop smoking?
The National Institute for Health and Clinical Excellence (NICE) issued guidance on 'Quitting smoking in pregnancy and following childbirth' in June 2010.5
The key recommendations were to monitor all women's smoking status throughout pregnancy by routine carbon monoxide measurement, to provide encouragement and support to quit smoking throughout the pregnancy and beyond, and to offer smoking cessation advice and a referral to a specialist service.

General practice staff can help by following up and asking their pregnant patients who smoked prior to conception if they were referred for help to quit. Although advice and a referral to an NHS stop smoking service (NHS SSS) is now routine practice amongst midwives, some women may prefer to receive support from their practice staff.

Carbon monoxide monitoring    
As under-reporting of smoking status amongst pregnant women is common, NICE recommended that a routine carbon monoxide (CO) breath test be carried out on all women at their booking appointment. This is now being implemented across the country. The aim of the test is to identify those women who need the option of personalised help and support to quit.

During pregnancy, there are strong medical reasons to routinely test for the presence of CO, as more than any other substance found in tobacco smoke CO presents the most immediate danger to the foetus.

The 1992 Royal College of Physicians report2 stated that with each cigarette a pregnant woman smokes, the blood flow through the placenta is reduced for about 15 minutes, causing the baby's heart rate to increase. It is also known that the carbon monoxide contained in inhaled cigarette smoke reduces the oxygen-carrying capacity of a foetus by about 40%. This affects the growth rate of the baby, and babies of smoking mothers are an average of 200g or 6oz lighter at birth than babies of non-smoking mothers.

Many younger women are not aware that carbon monoxide enters their blood stream as a result of their smoking habit and its worthwhile taking the time to explain why this is a problem to their baby. If you have a CO monitor available, offer to do the CO test and interpret the results, as often these women are not making a properly informed choice about the dangers to their foetus from their smoking habit.

Another benefit of offering the CO test at other times in the pregnancy is that women exposed to second hand smoke can be identified and supported to reduce their exposure. Occasionally a non-smoker can have a high CO reading due to a faulty gas device. In this situation suggest they call the free Health and Safety Executive gas safety advice line (see Resources).

Helping women assess the risks of smoking
NICE also recommends that all conversations about smoking in pregnancy are handled in a positive, non-judgmental manner, which is usual practice amongst primary care staff. Try starting a conversation by exploring her concerns and attitudes towards smoking in this pregnancy and any factors that may influence her motivation to stop smoking.
Asking questions like these can give you more insight:

  •     Did you plan to be smoking in your pregnancy?
  •     What have you heard about the problems of smoking during pregnancy?
  •     Would you consider quitting now you are pregnant?

If she replies “I think my smoking will help me have a smaller baby,” follow with:

  •     What do you mean by a 'smaller' baby?
  •     Have you ever wondered how smoking can cause a baby to be smaller?
  •     May I explain this? (Describe how CO in the blood stream reduces the oxygen flow to the baby resulting in them often being less mature and developed rather than just small).

Women who 'cut down' their smoking
Pregnant women who change their smoking habits are more likely to cut down than give up. However, cutting down on smoking has little beneficial effect on the outcome of the pregnancy. Women who stop smoking at any time before conception have infants of the same birth weight as those born to women who have never smoked.  

While stopping in the first three months of pregnancy reduces the impact of smoking on birth weight, cutting down does not reduce the risk of having a low birth weight baby. Many women who cut down do not actually reduce their intake of toxins from cigarettes because they suck more heavily on the ones they still use, taking more tar and nicotine in from each cigarette.6
If one of your patients says she has 'cut down' on her smoking in pregnancy, explore her reasons further by asking:

  •     What made you decide to do that?
  •     How much were you smoking before - and now?
  •     Are there any times when it's hard for you to stick at that number?
  •     Cutting down can be harder than stopping for some people - how have you found it?

Explain how stopping smoking altogether can reduce the stress of managing just to smoke a few cigarettes each day. Maintain a positive patient-practitioner relationship to empower her to make her own decision regarding quitting smoking. If she is ambivalent or states continued smoking is her preference keep a record and offer to revisit the subject when you see her again. If she considers quitting, refer to the practice specialist or local NHS Stop Smoking Service for advice and support.

Partners who smoke
Pregnant smokers are less likely to quit if their partner smokes or are unsupportive during their quit attempt.8 It is therefore important to encourage partners of pregnant smokers to be supportive and to offer stop smoking support to the woman's partner.
It's not easy for the woman in that situation especially if her relationship is unstable. Try asking:

  •     What does your partner think of you trying to stop smoking?
  •     Is there something more he could do to support you? For example, can you ask him to smoke away from her, not to leave his smoking materials around or to offer you a cigarette?

Try to encourage her by congratulating her for trying and reaffirm the benefits to her baby of being smoke-free.

Protecting babies from passive smoke
Children of parents who smoke tend to suffer from a range of respiratory problems such as asthma or bronchitis. They are also more vulnerable to admission to hospital in the first six months of life and SIDS.

In general practice, whenever a baby is brought in to see you for a health check, take the opportunity to ask what the family have heard about the dangers of passive smoke. Ask what they already do to keep their baby safe. If they seem unsure of the problem, explain that babies are adversely affected by cigarette smoke and it is not about the parents having to stop smoking but instead to keep the infant free from smoke. According to the situation, try asking:

  •     If the baby is able to be kept in a smoke-free atmosphere.
  •     If not, can the baby's room be kept smoke-free?
  •     Can windows be opened to provide ventilation in the home?
  •     Could they ask family and friends not to smoke near the baby or to smoke just before visiting?

Despite the issues and dangers being well known, many women continue to smoke throughout their pregnancy. Practice staff generally have good relationships with their patients and their advice is trusted. Addressing smoking in pregnancy will not ruin these relationships, and by asking some of the questions suggested in this article and engaging with pregnant women at every opportunity, more women may be helped to quit smoking and give birth to healthier babies.

1.     The NHS Information Centre. Health Survey for England - 2010: Trend tables. 2011. Available at:
2.     Royal College of Physicians. Smoking and the young. London: Royal College of Physicians; 2010.
3.     British Market Research Bureau. Infant feeding survey 2005. A survey conducted on behalf of the Information Centre for Health and Social Care and the UK Health Departments. Southport: The Information Centre; 2007.
4.     Baxter, S, Everson-Hock, et al. Factors relating to the uptake of interventions for smoking cessation among pregnant women: a systematic review and qualitative synthesis. Nicotine Tob Res 2007;12(7): 685-694.
5.     National Institute for Health and Clinical Excellence (NICE). NICE Public Health Guidance 26. How to stop smoking in pregnancy and following childbirth. London: NICE; 2010.

6.     Bolling K, Owen L. Smoking and pregnancy. A survey of knowledge, attitudes and behavior. London: HEA; 2006.
7.     Dempsey D, Jacob III P, Benowitz NL. Accelerated metabolism of nicotine and cotinine in pregnant smokers. J Pharmacol Exp 2002;301(2):594-598.
8.     Aveyard P, Lawrence T, Evans O and Cheng KK. The influence of in-pregnancy smoking cessation programmes on partner quitting and women's social support mobilization: a randomized controlled trial. BMC Public Health 2005;5:80.

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