The most known effects of smoking are lung diseases, cancer, and other health problems, but it also adversely affects the fertility of men and women. Most couples who smoke and are trying to conceive will take usually longer to get pregnant than people who don’t.
Male Infertility: smoking and impact on fertility in men
Smoking has the following negative impacts on a male partner’s fertility:
Functioning of testis: The key functions of the testis are the production of the male hormone (androgen) and the production of sperms. Cigarette smoking may lead to a reduced testosterone level i.e. reproductive hormones and lower quality of sperms are produced (low count or low mobility).
Smoking and Impact on Semen Quality: Smokers show notably poorer sperm density and it also affects sperm morphology especially the head portion of sperm (Smokers have more round-headed sperms). More sperm abnormalities have been observed in heavy smokers. This results in the hampered functioning of the sperm membrane and the ability of sperms to undergo capacitation. Motility of sperms is also reduced and the condition worsens in the heavy smoking men. This is how male infertility and smoking are associated.
Physical problems such as troubles with ejaculation or maintaining erection are common.
Effect on Female Fertility
Now let us learn smoking and impact on fertility in women. Both active and passive smoking can have a huge impact on fertility in women or in other words women who don’t smoke but are exposed to passive smoking also have lower conception rates.
There are direct and indirect effects on every stage of fertility from hormonal production, egg maturation, to embryo development as follows:
Women are born with a set of eggs; these eggs when exposed to toxic elements from smoke are damaged. This increases the chances of miscarriages or even affecting ovaries (premature aging of ovaries). Some studies also indicate that DNA material in eggs may also get damaged and thus affecting a child’s health.
The effect of smoking can also be seen on hindered menstrual cycle or irregular menstrual function. Such menstrual irregularity is an indicator of problems with ovarian functioning and affects women’s conceiving ability. Similarly, studies have reported heavy periods, severe pain, and frequent and irregular periods among smokers, especially heavy smokers.(1)
Smoking may also reduce the number of eggs in females and may also affect the duration of menstrual cycling. Thus women who smoke may hit the menopausal period 2-3 years earlier than non-smokers.
Smoking can affect the structure of fallopian tubes by causing blockages in tubes. This leads to obstruction in eggs release or increased risk of pregnancy formed inside the tubes instead of the uterus (ectopic pregnancy)
Another side effect of smoking is unnatural changes in uterine lining making it difficult to implant an embryo.
Effects of Children
Despite the risks, many women still smoke during pregnancy, thus affecting the fetal development and increased risk for defects of the face such as orofacial clefts, defects related to the heart, muscles, or digestive system altogether. Based on many studies, the birth defects that are positively associated with maternal smoking and a non-chromosomal birth defect among women who smoked during pregnancy are more common than compared with non-smokers (2). The children may suffer from problems related to bone and limbs.
Effects on fertility of child: Some studies have examined the age of puberty or start of menstrual periods in child and its relation to parental smoking and it has been reported that daughters whose mothers have been smoking during pregnancy have reached the menstrual period earlier by several months. It may also change the testosterone profile of the young women.(3)
In the context of male reproductive health (male child), smoking during pregnancy causes long-term defects in male offspring fertility. This results in significant germ cell damage, sex hormone metabolism, damaged DNA of sperms affecting motility and fertilization potential in adult life, and in some cases may impair fertility of male child.(4)
Smoking can affect the success rates of assisted reproductive fertility treatments as well. Smoking affects every stage of women’s reproductive cycle from egg production; it also decreases the ovarian reserve. The outcomes of IVF and ICSI largely depend upon the quality of eggs and sperms collected, there are a large number of failed fertilization. It’s not only the female part, but the smoking of men can adversely affect the IVF outcome. As per one of the studies, the chances of conception by ICSI or IVF in women with smoking male partners were 22% and were 38% with nonsmoking partners.(5)
Pregnancy complications: smoking may trigger involuntary termination of pregnancy, increases the risk of premature birth or low birth-weight. There are more chances of ectopic pregnancy putting mother and baby’s life in critical situations. This is mainly due to the alteration of the DNA of sperms under the influence of smoking.
Chewing tobacco has equal amounts of side effects as that of smoking. Tobacco contains a large number of compounds that are known to have toxic effects on reproductive health. It affects right from the puberty period, fertility of men and women, and even maintaining pregnancy. It also has long-lasting effects on the overall health of a person. Nicotine may also interfere with pregnancy by causing defects to fallopian tubes. We have learnt about smoking and impact on semen quality and hence on the health of the baby; chewing tobacco also has adverse effects on male children such as damage to DNA and/or chromosomes in gametes and other long-term consequences.
Cigarette smoking is one of the main causes of infertility in men and women. The effects of smoking from the puberty stage, fertility to post-pregnancy effects on children are drastic. As there is an important impact of lifestyle factors on the success of IVF and ICSI; smoking also affects your chances of conception during these assisted reproduction treatments. Thus if you are planning for a baby or improve your general health, your doctor will recommend you abstain from smoking in order to recover your fertility and your overall health.