by Eve Redstone

Created on: June 30, 2008

Semen quality is one of the deciding factors in whether a couple can successfully conceive a baby. Normal ejaculate contains about forty million spermatozoa. This seems like a vast number, but it is normal for up to twenty five per cent to be dead, and only thirty percent to be considered normal in appearance. It is normal for as few as twenty-five percent of the spermatozoa to be normal in appearance and swimming forward vigorously.

The testes produce sperm continuously in a cycle that takes over two months to complete. The length of this cycle means that the quality and quantity of an individual's sperm can vary a great deal from day to day according to exterior factors such as diet, temperature and exposure to toxins. These toxins include the chemical ones we traditionally think of such as pesticides, the recently publicised ones such as phthalates, and cigarette smoke.

The advent of IVF has led to greater attention being paid to the factors that contribute towards fertility in both women and men. The role of smoking in female fertility has been clearly defined. Papers have been published with the exact effects that smoking has on female egg production, implantation of fertilised eggs, and subsequent risk of miscarriage and premature birth. The risk is known for both smoking, and the inhalation of second hand smoke.

The picture for the effect of smoking on sperm quality is less clear because of the many factors that can cause changes in sperm quality. The data available does suggest that smoking by either partner will reduce sperm quality in the man. This includes a lower total number of spermatozoa in the ejaculate, and an increase in dead and malformed spermatozoa. When combined with the effects that smoking has on the female partners fertility smoking in the male partner can be enough to cause infertility in an otherwise healthy couple.

Loni Burman at the University of Buffalo medical school has studied the effects of smoking on spermatozoa. Smoking has two effects on sperm according to his team, it reduces overall sperm quality by a measurable amount, and it also stops the adhesion of the sperm to the egg, a vital part in the conception process. This lack of adhesion can prevent successful fertilization in the body or the test tube. Further research has shown that smoking also affects the DNA carried by the sperm, and may lead to problems in later life for the babies of male smokers.

In infertile couples the woman will often stop smoking early in the process, sometimes in order to be accepted onto a program. The male partner may put off this move until pregnancy is confirmed, but what this research is showing is that the male partner has to stop smoking too. Because of the length of the production cycle for healthy sperm the man needs to stop smoking, or being exposed to cigarette smoke, for at least two months before changes on sperm quality are noticed.

A change in smoking habits will improve sperm quality, but other factors such as temperature, diet, stress and possible infection must be addressed to in order to achieve maximum sperm quality.

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