Smoking is associated with a dose-dependent compromised reproductive outcome. This is true not only for actively smoking women, but also for non-smoking women with smoking partners or otherwise exposed to a smoking environment.
A problem for analysis is posed by the lack of unanimity concerning the definition of who is a smoker.
EFFECT OF SMOKING ON NATURAL REPRODUCTIVE POTENTIAL.
- Risk of infertility may be twice as high for smokers.
- Need more time to get conceived
- Are less likely to conceive spontaneously
- Higher risk of miscarriage in the first trimester.
- Can reach Menopause a few years earlier.
Importantly, the impact of passive smoking on women’s natural fertility is only slightly less than that of active smoking.
In smoking men, sperm quality and concentration are often found to be reduced. There is also evidence that smoking may lead to DNA damage in sperm. However, data on whether smoking effectively influences male fertility are inconclusive.
It is estimated that most of the reproductive effects of smoking will be reversed after 1 year after cessation.
EFFECT OF SMOKING ON IVF RESULTS:
- Smoking also has a negative influence on IVF outcome
- Smoking women need up to twice the number of IVF cycles to conceive as non-smokers.
- The negative impact of smoking is more marked in older women, which may reflect an accelerating effect on oocyte depletion.
- The effect of smoking on IVF outcome is comparable to an increase in female age with 10-year, more specifically from age 20 to 30 years.
- A strong relation between the number of smoking years during the women’s life time and her risk of not conceiving through IVF has also been found.
- Although decreases in sperm density and motility and abnormalities in sperm morphology have been observed in men who smoke, available data do not demonstrate conclusively that smoking decreases male fertility.
EFFECT OF SMOKING ON PREGNANCY COMPLICATIONS AND OUTCOMES Smoking during pregnancy is regarded as an important preventable risk factor for an adverse pregnancy outcome.
Higher risks are reported for
- Spontaneous miscarriage,
- Placental complications,
- Fetal growth restriction,
- Preterm birth,
- Stillbirth and
- Early neonatal death.
Several studies have shown that these higher risks are dose-dependent.
They are also open to being reversed (as shown in subsequent pregnancies of the same women) by smoking cessation.
The relation with lower birthweight is a longstanding and consistent finding. Women smoking 10 cigarettes or more per day bear children that on average weigh 200 g less.
EFFECT OF SMOKING ON THE HEALTH OF THE CHILD
- Higher risk of having a child with oral-facial clefts.
- Higher overall risk of having children with congenital abnormalities (Not conclusive).
- Higher risk of Sudden Infant Death Syndrome and of childhood respiratory disorders
- Higher risks of childhood leukaemia and other cancers need further exploration.
- Possible association with behavioural and psychiatric disorders.
- Lower birth weight of infants of smoking mothers may expose them to higher risks of adult disease.
- Possible adverse effect of maternal smoking on semen parameters in male offspring.