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Women and smoking (C-Gen 5)


College Statement
C-Gen 5
1st Endorsed: November 2001
Current: November 2011
Review: November 2014

 

Contents 

1. Smoking and pregnancy 
2. Smoking effects in pregnancy 
3. Strategies to reduce smoking in pregnancy 
4. Nicotine replacement therapy (NRT) 
5. Smoking and other areas of women's health 
6. References

 

1. Smoking and pregnancy

Recent data indicate about 17 per cent of women smoke during pregnancy1, 2. Thus smoking is a significant health problem in pregnancy. The percentage is often higher in younger pregnant women, women attending public antenatal clinics, indigenous women and in women of lower socio-economic groups. Between 25 and 40 per cent of women who smoke will cease smoking on becoming pregnant3 but about 60 per cent will resume smoking after the pregnancy. Circumstances influencing smoking are complex and, in many instances, different for women than men. Heavy cigarette use, poor education, low socio-economic status, depression and denial that smoking will affect the fetus and cohabitation with a smoker are all factors that reduce the chance of successful smoking cessation during pregnancy. Women should be given a clear strong message regarding the risks to herself and her fetus.

Cigarette smoking is a form of substance abuse and the successful management of smoking cessation in pregnancy is enhanced by strategies which address the underlying factors that encourage women to initiate smoking in the first instance. Issues such as depression, low self-esteem, and difficult personal or social circumstances should be considered when encouraging women to cease smoking during pregnancy.

  • The components of cigarette smoke most often linked to adverse effects are nicotine, tar and carbon monoxide.
  • Nicotine has stimulant properties resulting in catecholamine release with consequent tachycardia, elevation of blood pressure and vasoconstriction. Reduction of uterine blood flow has been documented.
  • Tar contains aromatic hydrocarbons, heavy metals and nitrosamines.
  • Carbon monoxide avidly displaces oxygen from haemoglobin and reaches significant concentrations in fetal blood.

There is an increased recognition of the effects of passive smoking. The fetus receives constituents of cigarette smoke via the placenta and fetal physiology can be demonstrated to be altered by maternal smoking4.

 

2.  Smoking effects in pregnancy

These have been reviewed5, 6,7,28.

2.1 Reduced fertility

There is increasing data on the impact of smoking on fertility. Conception is delayed by an average of 2 months, and a 60% increase in infertility has been reported among smoking women. Smoking is associated with reduced IVF success. These effects seem to be reversible after cessation of smoking28.

2.2  Miscarriage

There is a suggestion of a marginal increase only, although mostly among heavy smokers.

2.2 Fetal anomalies

Recent data confirms an association with smoking and some major malformations, most notably cardiovascular defects, musculoskeletal defects, facial and gastrointestinal defects. Although the increases in risk is modest, this information should be outlined to women who smoke prior to or during pregnancy to encourage women to cease smoking during pregnancy26.

2.3 Pre-term birth and preterm PROM

Current evidence indicates an increase in prematurity associated with smoking in pregnancy6.  Strategies directed at smoking cessation have resulted in a reduced incidence of prematurity12.

2.4  Low birth weight

Evidence exists to show a dose related reduction in fetal weight 6,8. In addition, increasing maternal age is an independent factor, especially age greater than 35. The maximum reduction in birth weight for heavy smoking is of the order of 450 to 500 grams in weight9 Cessation of smoking in pregnancy as late as the second trimester has been shown to have benefits for fetal growth, although fetal weight will not return to normal.

Fetal growth restriction has been associated with the development of adult diseases including obesity, type 2 diabetes, dyslipidaemia, cardiovascular disease (hypertension, coronary artery disease and stroke) and cognitive problems.

2.5  Hypertension

Although there is catecholamine stimulation by nicotine, paradoxically preeclampsia and gestational hypertension are less common in smokers9. If pre-eclampsia occurs, however, it tends to be worse than in non-smokers.

2.6  Antepartum and intrapartum haemorrhage

Placental abruption increases in smokers,6 with a doubling of the risk for smokers who

consume greater than 20 cigarettes a day.

2.7 Stillbirth.

Smoking is a significant and independent risk factor for both antenatal and intrapartum stillbirth.


3.  Strategies to reduce smoking in pregnancy

3.1  Sudden infant death syndrome (SIDS)

Smoking is a major risk factor for SIDS. SIDS is more common in the infants of smokers, both women who smoke during pregnancy and infants whose parents smoke. There is a significant dose dependent relationship between smoking and SIDS; one study has also confirmed that the risk of SIDS was reduced with smoking cessation during pregnancy27.

3.2 Reduced lung function, increased respiratory illness. There is a slight, but significant impact on childhood lung function, and asthma is increased among women who smoke. 

3.3 Smoking has been associated with a wide range of cognitive and behavioural disorders. Prenatal tobacco exposure is associated with a higher risk of offspring themselves becoming smokers, and increased rates of childhood obesity, even after adjustment for potential confounding variables28.


4.  Nicotine replacement therapy (NRT)

4.1  Coagulation

Thrombosis is more common in smokers, and pregnancy is a pro-thrombotic state. Smoking is an independent risk factor for DVT after caesarean section.

4.2 Increased respiratory morbidity

Smoking during pregnancy is associated with increased maternal respiratory compromise. There is a higher likelihood of ICU admission in the setting of influenza, and a higher risk asthmatic morbidity

4.3 Increased anaesthetic morbidity

 

5.  Smoking and other areas of women's health

5.1 It has been recognised that health promotion programs, health practitioner input to patient education and counselling programs have all resulted in a reduction in smoking incidence in pregnancy.

5.2 Health care providers play an important role in promoting the cessation of smoking by pregnant women. Each consultation should be considered and utilised as an opportunity to counsel. Referral can be made to programs such as QUIT13.

5.3 Maternity units should develop strategies to promote smoking cessation in pregnancy. Such strategies should be taught to health care providers who advise and care for pregnant women to more effectively counsel those women about smoking cessation.

5.4 In view of the high relapse rate after birth, strategies should be provided to support women after birth in an attempt to increase the likelihood of them remaining smoking free long-term.

5.5 In addition, in relationships where the male partner is the sole smoker, advice should be offered that smoking should not occur in the house or near the pregnant woman.

5.6 All counselling activity should avoid strategies that promote guilt or low self-esteem.

 

6.  Nicotine replacement therapy (NRT)

NRT has been proven to help non-pregnant patients cease smoking.

Significant clinical data on the use of NRT in pregnancy is scarce considering the scale of use of tobacco products by pregnant women. Large-scale trials of NRT have not been undertaken. The largest identifiable randomised controlled trial of NRT in pregnancy involved only 250 women in two groups14. Studies assessing clinical safety of NRT have involved very small numbers of patients in studies lasting six and 21 hours15,16. Frequent animal studies have been used to extrapolate data to humans, however this data has often been contradictory.

6.1  Current status of nicotine replacement therapies in pregnancy in Australia.

Nicabate patches (SmithKline Beecham), Nicorette chewing gum (Pharmacia), Nicorette inhaler (Pharmacia), and Nicorette patches (Pharmacia) are all currently categorised 'D' with regard to pregnancy use.

6.2  Evidence for effectiveness of NRT and its safety in human pregnancy

6.2.1    Teratogenesis

Human data does not support the earlier animal work indicating teratogenesis of nicotine. US drug categorisation was reduced from 'X' to 'C' in 1992 for Nicotine polacrilex. The transdermal systems are 'D' with evidence of animal harm, but no human harm. Not recommended in first trimester.

6.2.2    Smoking cessation

There is no evidence in the one longitudinal study of 250 women, that NRT reduces the rate of cigarette smoking in pregnancy. This study, however, confirmed the meta-analysis data indicating that counselling activity has a significant role in cessation activity. Self reported smoking cessation was 4.8 times greater for women participating in the study compared to women one year before and one year after the study.

6.2.3    Clinical outcome

The one study of 250 women showed a positive clinical outcome with regard to fetal weight. Over the whole study NRT resulted in an increase in average fetal weight of 280 grams. The percentage of babies <2500 grams was three per cent for NRT versus nine per cent for placebo (RR 0.4, CI 0.1, 1.1).

6.2.4    Clinical parameters

Short term administration of transdermal patches, over eight hours, resulted in an increased incidence of reduced baseline FHR variability with an increase in baseline FHR in a study of 15 women.

6.2.5    Clinical use of NRT

In Boston, USA a study of 25 local obstetricians showed 44 per cent advised or recommended NRT in pregnancy. Ninety-two per cent indicated they would do so if safety data were available17.

6.2.6    Serum nicotine levels

Nicotine levels are lower for women on NRT than for women smoking ten or more cigarettes a day. The diurnal serum nicotine level seen in smokers can be mimicked in NRT. Using patches for no longer than 16 hours during the day with removal overnight results in lower serum levels.

6.3  Summary of use of NRT in pregnancy

NRT appears to be an attractive clinical option for clinicians dealing with heavy cigarette smoking in pregnant women. Clinical data which are limited, suggest that NRT might be an option to reduce the fetal risks. However compared to non-pregnant women, there is little direct evidence to support an increase in smoking cessation using NRT during pregnancy. Counselling and behaviour therapies have been shown to increase the rate of smoking cessation in pregnant women.

Unfortunately the lack of safety data, and significant clinical studies, would preclude a recommendation that NRT be routinely advised to pregnant women who smoke cigarettes. In spite of this there have been authors recommending use of NRT in carefully monitored clinical settings for those women who smoke very heavily and are unable to cease with non-pharmacological therapies19, 20.

NRT is not currently licensed for use in pregnant women. However the benefits of NRT appear to outweigh the harmful effects of smoking.  Accordingly some health jurisdictions subsidise the use of NRT in pregnant women.


7.  Smoking and other areas of women's health

Cigarette smoking is associated with a number of other adverse health conditions in women21.

7.1  Cardiovascular and thrombo-embolic disease increases with age.

Smoking accelerates the risk of cardiovascular disease, and although ischaemic heart disease is uncommon in women of reproductive age, the risk for current smokers is 2.5 times that of non-smokers22.

7.2  Chronic respiratory disease.

7.3  Osteoporosis and its consequences.

7.4  Accelerated skin changes.

7.5  Cervical pre-invasive and invasive disease.

7.6  Cancers of lung, oro-pharynx and bladder. It may be implicated in a number of other cancers


Given the proven benefit of replacement therapy in aiding smoking cessation, NRT plus supportive counselling should be offered to, and discussed with, non-pregnant women who smoke and are attending health care facilities. Real long-term health benefits exist for those women who are able to cease smoking permanently. A Finnish study utilizing a 28 year follow-up showed a 30% reduction in mortality risk in those women who ceased smoking in pregnancy23. This points the way in advising those women not pregnant, but who smoke.

A good overview of women’s health issues with smoking can be found at the US Surgeon General’s Report 2001 24 ‘Woman and smoking’.

 

References 

  1. Trotter L, Mullins R, Freeman J. Key findings of the 1998 and 1999 population surveys, QUIT Evaluation Studies No 10, Centre for Behavioural Research in Cancer 1998-1999. 
  2. Mohsin M, Bauman AE. Socio-demographic factors associated with smoking and smoking cessation among 426,344 pregnant women in New South Wales, Australia. BMC Public Health. 2005 Dec 21;5:138
  3. Panjari M, Bell R, Bishop S, Astbury J, Rice G, Doery J. A randomised controlled trial of a smoking cessation intervention during pregnancy. Aust NZ J Obstet Gynaecol 1999; 39:312-317.
  4. Coppens M, Vindla S, James D, Sahota D. Computerised analysis of acute and chronic changes in fetal heart rate variation and fetal activity in association with maternal smoking. Am J Obstet Gynecol 2001;185(2):421-426.
  5. Newnham JP, Smoking in pregnancy. Fetal Medicine Review 1991; 3: 115-132. 6 Brennan BG, Smoking in pregnancy. J Soc Obstet Gynaecol Can 1997; 19:1405-1410.
  6. The Health consequences of smoking. A report of the US Surgeon General, 2004. at http://www.cdc.gov/tobacco/sgr/sgr_2004/index.htm
  7. Seidmann DS, Stevenson DK. Nicotine replacement therapy during pregnancy. JAMA 1992;267:1922 (letter).
  8. Obstetric and Neonatal Report, Tasmania, 1981. Smoking and Alcohol Appendix.
  9. Conde-Agudelo A, Althabe F, Belizan JM, Kafury-Goeta AC. Cigarette smoking during pregnancy: A systematic review. Am J Obstet Gynecol 1999;181:1026-1035.
  10. Blair PS, Fleming PJ, Bensley D, Smith I, Bacon C, Taylor E, et al. Smoking and the sudden infant death syndrome: results from 1993-5 case-control study for confidential enquiry into stillbirths and deaths in infancy. BMJ 1996; 313:195-198.
  11. Brooke H, Gibson A, Tappin D, Brown H. Case-control study of sudden infant death syndrome in Scotland, 1992-5. BMJ. 1997 May 24;314(7093):1516-1520.
  12. Lumley J, Oliver S, Chamberlain C, Oakley L. Interventions for promoting smoking cessation during pregnancy. The Cochrane Database of Systematic Reviews 2004, Issue 4. Art No.: CD001055.pub2. DOI: 10.1002/14651858.CD001055.pub2.
  13. Walsh RA, Lowe JB, Hopkins PJ. Quitting smoking in pregnancy. Med J Aust 2001; 175: 320-323.
  14. Wisborg K, Henriksen TB, Jesperson LB, Secher JS. Nicotine patches for pregnant smokers: a randomised controlled trial. Obstet Gynecol 2000;96(6):967-971.
  15. Wright LN, Thorp JM, Kuller JA, Shrewsbury RP, Ananth C, Hartmann K. Transdermal nicotine replacement in pregnancy: maternal pharmacokinetics and fetal effects. Am J Obstet Gynecol 1997; 176(5):1090-1094.
  16. Oncken CA, Hardarttir H, Hatsukami DK, Lupo VR, Rodis JF, Smeltzer JS. Effects of transdermal nicotine or smoking on nicotine concentrations and maternal-fetal hemodynamics. Obstet Gynecol 1997; 90(4): 569-574.
  17. Dolan-Mullen P, Ramirez G, Groff J. A meta-analysis of prenatal smoking cessation interventions. Am J Obstet Gynecol 1994; 171: 1328-34.
  18. Oncken CA, Pbert L, Ockene JK, Zapka J, Stoddard A. Nicotine replacement prescription practices of obstetric and pediatric clinicians. Obstet Gynecol 2000; 96(2): 261-265.
  19. Benowitz NL. Nicotine replacement therapy during pregnancy. JAMA 1991;266: 3174-3177.
  20. Hackmann R, Kapur B, Koren G. Use of the nicotine patch by pregnant women. (Correspondence) N Engl J Med 1999; 341(22):1700.
  21. Special Symposium. Smoking and reproduction. Hughes E, guest editor. J Soc Obstet Gynaecol Can 1997;19:1399-1424.
  22. Rowe T. Smoking and contraception, in smoking and reproduction. J Soc Obstet Gynaecol Can 1997; 19: 1399-1403.
  23. Rantakallio P, Laara E, Markku K. A 28 year follow up of mortality among women who smoked during pregnancy. BMJ 1995;311:477-480(19 August)
  24. Woman and smoking – A Report of the US Surgeon General 2001. http://www.cdc.gov/tobacco/sgr/sgr_forwomen/index.htm
  25. Lumley J, Chamberlain C, Dowswell T, Oliver S, Oakley L, Watson L. Interventions for promoting smoking cessation during pregnancy. Cochrane Database of Systematic Reviews 2009, Issue 3. Art. No.: CD001055. DOI: 10.1002/14651858.CD001055.pub3.
  26. Hackshaw A, Rodeck C, Boniface S .Maternal smoking in pregnancy and birth defects: a systematic review based on 173 687 malformed cases and 11.7 million controls. Hum Reprod Update. 2011 Sep-Oct;17(5):589-604. Epub 2011 Jul 11.
  27. DiFranza JR, Aligne CA, Weitzman M. Prenatal and postnatal environmental tobacco smoke exposure and children's health. Pediatrics. 2004 Apr;113(4 Suppl):1007-15
  28. Murin S, Rafii R, Bilello K. Smoking and smoking cessation in pregnancy. Clint Chest Med. 2011 Mar;32(1):75-91

 

Disclaimer

This College Statement is intended to provide general advice to Practitioners. The statement should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient.

The statement has been prepared having regard to general circumstances. It is the responsibility of each Practitioner to have regard to the particular circumstances of each case, and the application of this statement in each case. In particular, clinical management must always be responsive to the needs of the individual patient and the particular circumstances of each case.

This College statement has been prepared having regard to the information available at the time of its preparation, and each Practitioner must have regard to relevant information, research or material which may have been published or become available subsequently.

Whilst the College endeavours to ensure that College statements are accurate and current at the time of their preparation, it takes no responsibility for matters arising from changed circumstances or information or material that may have become available after the date of the statements.

 
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