Smoking and Fertility - Generational Destruction
Ask a five-year-old about smoking and he'll probably tell you that cigarettes stink, they make your breath smell bad, and they can give you cancer and kill you. Little kids know these things. Why are adults so slow to pick up the message?
It Starts with the First Cigarette as a Teenager
Adult smokers most frequently started off smoking in their teens and although teen smoking had been on a sharp decline since the mid to late 1990s, recent data shows that the adolescent smoking rates are rising slightly again. Nearly one-quarter of all high school students reported smoking cigarettes in a slightly dated study of 2005. About 3,000 new teen smokers start every day. What's that got to do with fertility? They are the next generation and, if the current news is correct, 25 is the new 35 for women in terms of fertility. If women (and men) start smoking in their teens, the chances of being infertile by the time they reach their mid-twenties are pretty good.
Adverse Affect of Smoking on Sex Organs of Embryos
This information was actually borne out in two studies done in Europe. The studies have shed light on how smoking damages fertility, lending more weight to the idea that both mothers and fathers-to-be should stop smoking before attempting to conceive.
In the first study, the researchers found that a mother's smoking during early pregnancy dramatically reduces the numbers of germ cells - the cells that form eggs in females and sperm in males - and somatic cells - cells that form all other parts of the body, in the developing fetus. They believe this may have an adverse effect upon the fertility of the baby in later life.
The study, completed at the University Hospital of Copenhagen, Claus Yding Anderson, Professor of Human Reproductive Physiology and his colleagues examined 24 embryonic testes obtained after women had undergone legal abortion between 37 and 68 days after conception. Blood and urine samples were taken from the women and they answered questions regarding their lifestyle during pregnancy, including smoking and drinking habits.
This study found that the number of germ cells (those responsible for procreation) were reduced by more than half (55%) in the testes of embryos from mothers who smoked compared with those who did not smoke. The number of somatic cells was reduced by more than a third (37%). When the results were added to the findings on the effect of smoking on 28 female embryos, they found that germ cells in the ovaries and testes of embryos exposed to smoking were reduced by 41% compared with non-smoking mothers. The results showed that germ cells were more susceptible than somatic cells to the effects of smoke damage.
Chromosomes Affected in Men Who Smoke
The second study, completed in Homburg Saar, Germany, was lead by the head of the assisted reproductive laboratory in the Department of Obstetrics and Gynecology at the University of the Saarland, Professor Mohamed Hammadeh. His team of researchers looked at protamines in the sperm of men who smoked and compared them with non-smokers. Protamines are necessary for the formation of chromosomes during cell division, ultimately having an effect on future male fertility.
The study looked at the levels of protamines 1 and 2 in the sperm of 53 heavy smokers and 63 non-smokers. Protamines P1 and P2 are critical to the proper packaging of chromatin,the combination of DNA and proteins that make up chromosomes, called chromatic condensation. Poor packaging affects sperm adversely and is associated with lower chances of fertilization after intercourse, poor fertilization after IVF and ICSI and higher incidence of miscarriages.
The study also showed that the levels of oxidative stress were higher in smokers than non-smokers. Oxidative stress is the imbalance between oxygen-containing molecules, free radicals, and anti-oxidant compounds. It can cause damage to proteins and to DNA. It causes damage to sperm DNA in a variety of ways and the study results suggest that the induced oxidative stress brought on by cigarette smoking may have a significant negative impact on chromatin condensation in P2.
Who's To Blame?
If an infertile man or woman was born to a mother who smoked during pregnancy, it seems possible that their present infertility may be linked to their mother's smoking habit. Additionally, as smokers, they may be passing on the legacy to their future children.
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