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Reproduction

The reproductive toll of smoking is felt across the life span, from effects on child health to early menopause.

Sexual health

“Woman-specific is not always woman-positive."

The effect of smoking on sexual health is felt across the life span, from poor infant health to early menopause. However, women’s own health is sometimes given too little emphasis, both in research and health promotion messages.

General health

Menstrual problems
Women who smoke tend to suffer abnormal menstrual patterns and discharge, and more pain over several days. PMS is no worse, but smoking withdrawal symptoms are more frequent later in the menstrual cycle (luteal phase), and relapse is more likely. This may be of practical value for women timing a quit attempt.

Contraception
Smoking greatly increases risk of arterial disease associated with contraceptive pills. Risk of heart attack and stroke is increased roughly ten-fold, with greater risk for women over 45. There is also greater risk of subarrachnoid bleeding, and ‘mini-strokes’ or TIA (transient ischaemic attack).

Other sexual health
Pelvic inflammatory disease (PID) is more common among smokers, increasing chances of ectopic pregnancy, and long-term infertility. Recent studies show that more male smokers have erectile problems, and that their fertility is lower. Worry over ‘performance’ or failure to conceive may obviously damage sexual intimacy and pleasure.

Reproductive cancers

Cervical cancer
Differences in sexual behavior may increase risk for smokers. But smoking also reduces Langerhans cells, part of immune function. Infection with the viral agent HPV may last longer, and infected cells more quickly become malignant (HPV, human papilloma virus). Risk of death is roughly doubled (RR 2.1), though some studies show up to four-fold increase. Some women may benefit from advice during cervical screening.

Other cancers
Ovarian cancer is causally linked to smoking. However, earlier studies suggested that nicotine may weakly protect against breast cancer. As with endometrial cancer, this may be because oestrogen is lowered. Some recent work shows greater risk of breast cancer for some women smokers, perhaps of particular genetic type

Fertility
Smoking reduces fertility by around a third, but women smokers are three times as likely to try for a year or more.. Those who try for in vitro fertilization (IVF) also take longer to succeed. There are many causes of lower fertility. Fewer oocytes are produced, or ripen properly (oocyte maturation), with weaker ovulation response. Fertilization and implantation are less likely, and miscarriage more common. There is also concern that smoking limits the number of eggs available (ovarian reserve). More research is needed on combined effect of low body mass and smoking in some women.

Smoking in pregnancy
Smoking during pregnancy obviously reflects trends among young women, especially poorer young women. For example, in the UK more young women now smoke, and smoking during pregnancy has increased from 22-30% during 1992-99.

Pregnancy among smokers is less likely to result in a healthy baby, due to increased risk of miscarriage and perinatal death. A major US report named smoking as “probably the most important modifiable cause of poor pregnancy outcome”.

Smoking and the foetus

Establishing pregnancy
Women smokers have double the risk of ectopic pregnancy, which causes infertility and may endanger life (RR 2.5). More babies also miscarry, possibly because of malformation.
The effects of tobacco toxins impair placental growth and function. The placenta is also more likely to cover the cervix (placenta praevia), with greater risk of haemorrhage.

Foetal health
Foetal growth is reduced as the placenta is smaller, and toxins including nicotine, heavy metals and cyanide easily cross the placenta. New research suggests that the foetus is also exposed to the tobacco carcinogen NNAL. This carcinogen is found in the amniotic fluid of half of pregnant smokers (52%), but less than a tenth of non-smokers (7%), possibly increasing future cancer risk. Tobacco carcinogens are also found in the urine of smokers’ babies at birth.

Foetal haemoglobin links strongly to carbon monoxide, and oxygen levels are lower than normal. This is at a time when the brain develops rapidly. There may be a link with poor child development, and later behavior problems. However, the role of nicotine in pregnancy outcome is not yet clear, and use of nicotine gum may be considered.

Maternal health
Maternal health also suffers, with greater risk of vomiting and urinary infections, and bleeding in the later months. At the end of pregnancy, the membranes are more likely to break early.

Infant health
At birth smokers' babies weigh some 200gm less on average, with twice as many under 2,500gm, the WHO measure of ‘low birthweight’. One study found that heavy smoking reduces weight by nearly half a kilo (458 gm). These babies are smaller, not just thinner, and around 6-8 cm shorter. They are at greater risk of death, for example risk is up by a third (35%) among Swedish smokers of 20+ a day. It’s estimated that perhaps 10% of foetal and infant deaths in the Western world are linked to smoking. However two-thirds (67%) of British pregnant smokers believe low weight doesn't’t matter, as they think the baby will still grow.

Around a quarter of risk of sudden infant death (SID) is attributed to smoking in pregnancy, though later smoke exposure also has a role. Some evidence also suggests links with birth defects, and lower bone mass in infancy. New research also shows worse lung function, with airflow reduced by 3-6%, separate from effects of later smoking. This confirms previous reports of lung damage in early pregnancy.

Later health

Child health
Smokers’ children have poor respiratory health, and more chest and ear infections.
However, some extra health risk is linked to poverty or a smoky home. Small deficits in growth and reading age are apparent during childhood, and behavior problems are more likely.
A US study found a dose-related link to poor behavior in toddlers just under 2, while factors such as other drug use seemed to have no effect.

Adult health
Low birthweight may increase adult risk of heart disease, though evidence is clearer for men. British studies also suggest that smoking affects children’s reproductive organs. Smokers’ adult daughters are more likely to smoke themselves, apart from social influence. This may be due to higher maternal testosterone, which sets testosterone level in female children.

Menopause

We know relatively little about smoking and sexual health in mid-life. However, smokers reach menopause around 1-4 years earlier, and may suffer more symptoms, such as hot flushes.

CVD and osteoporosis
Risk of arterial disease increases sharply at menopause as oestrogen levels fall, especially for smokers. An increase in central obesity also promotes arterial disease. At this time total risk starts to approach that for men. Smokers also need higher levels of HRT for therapy to be effective, with possible increase in health risk.

Women smokers generally have weaker bones, since nicotine reduces the level of active oestrogen needed by bone-forming cells. Blood supply is also impaired. Deficits in bone mass are already apparent in teen smokers. However around menopause active oestrogen falls further. Risk of osteoporosis rises steeply, leading to painful disabilities and higher incidence of fracture. Risk of hip fracture from menopause to age 85 is up by half among women smokers (19-12%). This risk is in proportion to amount smoked, independent of body weight and exercise habits.

Sexual health promotion For more detail see Stopping smoking

Doctors’ advice on quitting is very cost-effective, and advice on contraception, pregnancy, child health, cervical screening or menopause may offer good opportunity. Family planning nurses could also have a role. A few projects have had some impact on smoking in pregnancy, but less so among poorer women, and relapse rates remain high. A major European conference recently concluded that pregnancy should not be seen in isolation from other initiatives.

Yet a Swedish project, repeated in Norway, has had considerable success. This project involved a specific counseling approach, which fits easily into everyday work, with the focus on women’s own health. Nearly all staff have received training in this method. There was also emphasis on using local statistics, for tracking and media interest. Pregnant women in Sweden are now less likely to smoke than their peers, with rates halving (31-15%) during 1983-97. Child-health nurses may also visit within the first four weeks, to talk over the benefits of staying stopped, and relapse then falls to 20% at 8 months.

Benefits of quitting
Some risk falls quickly after stopping smoking. For example: within six months cervical lesions shrink significantly, fertility recovers. Stopping even in later pregnancy improves birthweight and infant survival. There is less risk of early menopause and osteoporosis.

Action points
Promote and publicize research into: the long term implications of smoking and low body mass index for fertility effects of smoking on oocyte maturation and "ovarian reserve" the effect of smoking after the menopause smoking and hormone replacement therapy how smoking is linked to osteoporosis

References View references in this window

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