1. SECONDHAND SMOKE (SHS)
AND PREGNANCY
Mini-Lecture 3
Module: Tobacco and the
Reproductive System

2. Objectives of the Mini Lecture
GOAL OF MODULE: Increase students’ knowledge of the potential problems related to the impact of passive smoking on pregnancy.
LEARNING OBJECTIVES:
Students will be able to:
Understand the effects of secondhand smoke on pregnancy, fetal growth, and pregnancy outcomes.
Understand the importance of avoiding exposure to secondhand smoke during pregnancy and postpartum.
Explain the importance of giving cessation advice to pregnant women and their husbands.

3. Contents Core Slides: SHS and Pregnancy SHS and Fetal Growth
SHS and Pregnancy Outcomes
Why Avoid SHS?
Cessation in Pregnancy: For Whom?
GOAL OF MODULE: Increase students’ knowledge of the potential problems related to the effect of passive smoking on pregnancy.
LEARNING OBJECTIVES: Students will be able to understand:
Core Slides:
SHS Effect on Pregnancy: Evidence
SHS & Fetal Growth
SHS & Pregnancy Outcomes
Why Avoid SHS?
Cessation in Pregnancy: For Whom?

4. CORE SLIDES Secondhand Smoke (SHS) and Pregnancy Mini-Lecture 3
Module: Tobacco and the
Reproductive System

5. SHS and Pregnancy
Infertility
Spontaneous Abortion
Pre-term Birth
IUGR
SIDS
Notes:
Pregnant women who do not smoke may also be at risk from passive smoking at home, the work place, and other places. The concentrations of carbon monoxide and nicotine are 2.5 and 2.7 times higher respectively in side-stream than in main-stream smoke. An increase in the concentration of cotinine was observed in the urine of non-smokers who live with smokers, and in the amniotic fluid of non-smoking pregnant women chronically exposed to tobacco smoke.
Reference:
Ogawa H, Tominaga S, Hori K, Noguchi K, Kanou I, Matsubara M. Passive smoking by pregnant women and fetal growth. J Epidemiol Community Health. 1991; 45:164–8.
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Secondhand smoke increases the risk of all adverse reproductive outcomes including, infertility1
Ogawa et al. 1991

6. SHS and Fetal Growth Significantly related to low birth weight1,2,3
Adversely affects fetal growth3
Impairs female and male fertility3
Notes:
SHS—a complex mixture containing many developmental toxicants (e.g., polycyclic aromatic hydrocarbons, lead, nicotine, cadmium)—is an important source of indoor air contaminants. The evidence from epidemiological investigations on the effect of passive smoking on fetal growth is inconsistent. However, many studies have found that SHS exposure adversely affects fetal growth with an elevated risk of low birth weight.1,2,3 Recent studies have also shown a significant relation of low birth weight to the amount of paternal smoking, duration of tobacco smoke exposure, and serum cotinine concentration of non-smoking mothers. However, a study in China showed no effect of paternal smoking. The risk from passive smoking is a serious problem in Japan, and women of reproductive age are highly likely to be exposed to cigarette smoke at home and in the work place. A study in Japan reported a rather small effect of paternal smoking on growth retardation (gestation > 37 weeks and birth weight <2500 g) of babies from nonsmoking mothers.1 The impact of passive smoking on other reproductive outcomes is less clear; an elevated risk of female and male infertility has been observed in some epidemiologic studies.3
References:
Ogawa H, Tominaga S, Hori K, Noguchi K, Kanou I, Matsubara M. Passive smoking by pregnant women and fetal growth. J Epidemiol Community Health. 1991; 45:164–8.
Chen C, Wang X, Wang L, Yang F, Tang G, Xing H, et al. Effect of environmental tobacco smoke on levels of urinary hormone markers. Environ Health Perspect. 2005; 113:412–17.
Dejmek J, Solansk´y I, Podrazilová K, S˘rám RJ. The exposure of nonsmoking and smoking mothers to environmental tobacco smoke during different gestational phases and fetal growth. Environ Health Perspect. 2002; 110:601–6.
1. Ogawa et al. 1991; 2. Chen et al. 2005; 3. Dejmek et al. 2002

7. SHS and Pregnancy Outcomes
Dose–response relation between SHS exposure & early pregnancy loss1
Increased risk of preterm birth1
Increased risk of spontaneous abortion2
Notes:
Studies have shown that SHS in the absence of maternal smoking significantly increased the risk of preterm birth. Studies have also shown a significant dose–response relation between SHS exposure and dysmenorrhea and early pregnancy loss.1 An elevated risk of spontaneous abortion and sudden infant death syndrome has also been observed in some epidemiologic studies.2
References:
Chen C, Wang X, Wang L, Yang F, Tang G, Xing H, et al. Effect of environmental tobacco smoke on levels of urinary hormone markers. Environ Health Perspect. 2005; 113:412–17.
Dejmek J, Solansk´y I, Podrazilová K, S˘rám RJ. The exposure of nonsmoking and smoking mothers to environmental tobacco smoke during different gestational phases and fetal growth. Environ Health Perspect. 2002; 110:601–6.
1. Chen et al. 2005; 2. Dejmek et al. 2002

8. Why Avoid SHS?
Reproductive consequences of SHS as great as those observed in active smokers1
Clinical pregnancy rate in women exposed to SHS:
Similar to smokers
Significantly lower than non-smokers1
Notes:
Studies have demonstrated that the clinical pregnancy rate in women exposed to side-stream smoke is similar to that of women with mainstream cigarette smoke exposure and significantly lower than for non-smokers. As there was no difference in pregnancy rate when the smoking status of the partner was considered, they concluded that the reproductive consequences of secondhand smoking are as great as those observed in active smokers. These results will need to be confirmed in a prospective study with more objective measures of cigarette smoke exposure. Furthermore, there is inadequate research on the effects of cigarette smoke exposure on the female gamete and this research should be undertaken.
Reference:
Neal MS, Hughes EG, Holloway AC, Foster WG. Sidestream smoking is equally as damaging as mainstream smoking on IVF outcomes. Hum Reprod. 2005; 20:2531–5.
1. Neal et al. 2005

9. Cessation in Pregnancy: For Whom?
Best way to avoid SHS in pregnancy: Smoking mother/husband should be advised to quit
Husbands should at least NOT SMOKE around their pregnant wives
Encourage other family members to smoke outside the home/quit
Notes:
The best way to avoid SHS in pregnancy is to quit smoking for either mother or spouse or both. At the very least, husbands should avoid smoking in the home, around their pregnant wives and children. Similarly other family members should also be made aware of the hazards of SHS and encouraged to quit or smoke outside of the home.

10. Stop smoking for the health of your family!