Scientists shed new light on smoking and infertility
The scientists found that, compared with non-smokers, P2 concentrations were 14pc lower in the sperm of men smoking more than 20 a day. Photo: Getty Images
Mothers who smoke early in pregnancy may sow the seeds of infertility in their unborn sons by arresting the development of sperm cells, new research just published suggests.
Scientists found numbers of immature reproductive cells were dramatically reduced in male embryos exposed to the effects of tobacco. The findings echo those of previous research showing a similar effect on female embryos.
They were published in the journal 'Human Reproduction', alongside the results of a second study explaining why men who smoke may be putting their fertility at risk.
The new work reinforces public health advice urging couples to quit the habit before attempting to conceive.
The first team led by Professor Claus Andersen, from the University Hospital of Copenhagen in Denmark looked at 24 embryonic testes obtained from legally terminated pregnancies. The scientists compared the number of germ cells -- immature cells that become sperm in males and eggs in females -- in the testes of embryos from smoking and non-smoking women.
Overall, the number of germ cells in male and female embryos exposed to tobacco smoke were reduced by 41pc.
The scientists still do not know whether the reduction in embryonic cell numbers associated with smoking is permanent, or reflects a growth delay that is compensated for later.
The second study focused on levels of proteins called protamines that play an important role in the development of sperm in adult males.
A team led by Professor Mohamed Hammadeh, from the University of Saarland in Homburg Saar, Germany, looked at the levels of two protamines -- P1 and P2 -- in the sperm of 53 heavy smokers and 63 non-smokers.
The scientists found that, compared with non-smokers, P2 concentrations were 14pc lower in the sperm of men smoking more than 20 a day.
Prof Hammadeh said: "Physicians should advise infertile patients to quit smoking."
- John von Radowitz in London
Irish Independent
