Prenatal smoking reduces fertility

Mothers who smoke while pregnant may put their sons at risk of infertility later in life. The quality of men's semen has reportedly decreased over the past 60 to 70 years, with as many as one in four men, experiencing fertility problems as a result of their low sperm counts. Mother's smoking during pregnancy could be the cause of poor semen quality in their sons. This could be because the major metabolite of nicotine, cotinine, is known to cross the placenta, and may also be able to cross the barrier between the blood and the testes. Other components of tobacco smoke may also have a direct toxic effect on the fetal testes.Researchers at the Aarhus University Hospital in Denmark investigated semen quality in 347 men, in the age group of 18-21 years, born to women who participated in the study. In this study, conducted in the mid-1980s, pregnant women were asked about their smoking habits and other lifestyle information. The men were ranked according to the extent of their exposure to tobacco smoke in the womb. The findings indicate that 99 were born to non-smokers, and 248 men who were exposed to tobacco smoke in their mother's womb had a lower total sperm count than did the non-exposed men. Those exposed to the highest amounts of tobacco smoke-more than 19 cigarettes a day-had a 19 per cent lower semen volume, a 38 per cent lower total sperm count and a 17 per cent lower sperm concentration, than the unexposed men. The study also showed that the more cigarettes mothers smoke during pregnancy, particularly in their last month, the lower will be their sons' total sperm count in adulthood. An increasing number of couples seek infertility treatment, which makes poor semen quality and infertility a public health problem.

These results indicate that prenatal exposure to tobacco smoke has an adverse effect on semen quality. However, further research is required to substantiate the findings.

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