Surely a man’s occupation could not influence his reproductive health. Wrong. Concern about sperm has blossomed with the advent of IVF – In Vitro Fertilisation.

Before that, infertility was often considered a female problem, but IVF professionals report a significant and perhaps increasing proportion of cases in which there are problems with sperm. Debate rages about whether male fertility is on the decline.

In the heat of the argument about environmental and inherited problems, the impact of workplace damage to men’s reproductive health is often forgotten. Nevertheless, workplace exposures are well established among the environmental influences that can affect the number and quality of a man’s sperm.

The connection with work has been confirmed by the observations of fertility clinics such as the Queensland Fertility Group. Staff of this Brisbane clinic have noticed an association between the quality of the men’s semen, and the jobs those men do. The clinic’s scientific director, Keith Harrison, says the clinic has done some studies which show that the level of semen defects in men who come to the clinic for IVF varies according to their occupation.

Around one quarter of the office workers have significant semen defects, but blue-collar workers, such as transport workers, have about 50% more semen defects than office workers. “In occupations where they actually get their hands dirty, such as builders, electricians, painters, plumbers, there’s well over a 50% increase in the incidence of abnormal semen, and then in the guys who really get their hands dirty – motor mechanics, fitters, turners, welders, machinery operators – we see an almost doubling or even greater increase in the incidence of semen defects”, Mr Harrison said. He added that farmers, graziers and miners also have about twice the level of semen defects as office-based workers.

Workplace reproductive hazards
Workplace hazards to men include high doses of ionising radiation, for example X-rays, and about 200 chemical agents that may potentially affect reproductive health. Contact with certain agents can result in decreased libido and impotence, testicular damage or infertility, and damaged sperm. Many chemicals have not been checked for their effects on human reproduction.

In men, sperm are continuously produced by cells in the testicles. Workplace hazards may cause reproductive problems in a number of possible ways:- damage to the cells and tissue in the testicle such that sperm cannot be produced at all or not in large enough numbers for fertility- decrease in the hormones necessary for sperm production and sexual function- damage to the sperm themselves- damage to the nerves on which orgasm and ejaculation depend.

Agents that damage sperm are of particular concern because many do so by damaging the genetic material carried in the sperm (ie they cause mutations). If this occurs and that sperm fertilises an egg, then an abnormal pregnancy may occur, possibly leading to a miscarriage early in pregnancy, death of the foetus later in pregnancy or the birth of a child with an abnormality. Some types of workplace exposures can result in adverse reproductive outcomes, including infertility, impotence, miscarriage, foetal malformation, underweight babies and premature birth.

For example, excessive exposure to lead can lead to lack of libido, a decrease in sperm counts, an increase in the number of abnormal sperm, miscarriage and stillbirth. Similarly, men who work with DBCP (dibromochloropropane) – a type of fumigant – have a history of decreased fertility and sterility. A range of chemical, physical and biological agents can cause these types of outcomes. Workers in many occupations may be exposed to reproductive health hazards, especially if they work with chemicals, solvents or plastics.

And of course it is not only men’s reproductive health which can be affected, but also the potential for workplace damage to women’s reproductive capacity and to their unborn children is naturally a central focus for preventive efforts in this area.

Occupational effects on women’s bodies and the health of their babies have been extensively studied, and codes of practice and other resources have been developed to guide organisations in their duty of care relating to pregnant employees or those who may become pregnant. Effects on men’s reproductive health have historically received less attention, however, though occupational links with men’s reproductive problems are well established.

Other factors
Of course occupational hazards are not the only type of risk to reproductive health. According to Professor John Aitken from the Australian Centre of Excellence in Biotechnology and Development at Newcastle University, we are in all probability carrying around in our genes the consequences of our great grandparents’ hazardous exposures. For example, if your great grandfather smoked a pipe, it may have lead to his death from lung cancer, but the toxicants in tobacco smoke didn’t just impact upon his lungs, they also impacted upon the DNA integrity in his spermatozoa.“And because it’s in the germ line there is the potential for those effects to be carried on down through the generations”, Professor Aitken said.

Other risks to reproductive health may arise from influences such as sedentary work, the medications we use, or high temperatures. According to some researchers, oestrogens in the environment may pose a risk, though this is disputed by others.

The evidence for the last factor is “vanishingly small”, according to David Handelsman, Director of the ANZAC Research Institute at the University of Sydney, who is critical of what he says is a cult-like belief in falling sperm counts. “It has led to more research and that’s a good thing, but unfortunately the prompts for it, if they’re suitably alarming, often take root in a way that even good evidence won’t necessarily eradicate”, Mr Handelsman said.

Employers’ duties under the law
As with other health and safety hazards, employers must take a risk management approach to reproductive hazards. Reproductive risks may be involved in exposure to radiation, as well as to some metals, solvents, pesticides, pharmaceuticals, biological agents (eg infectious diseases) and other substances. Relevant Material Safety Data Sheets should be consulted, and specifications relating to reproduction, fertility and potential damage to the foetus should be checked.

Expert advice may also be required, as available information on reproductive effects is not always complete. Should a hazard be found to affect the reproductive system, steps must be taken to address the issue.

Risk control
Prevention of adverse effects can be accomplished by following the hierarchy of risk control. That is, hazardous exposures should be eliminated if possible, and if this is not practicable, they should be reduced, for example, by substituting a toxic substance with a less toxic one. Safe work practices that reduce workers’ exposure need to be established and followed, administrative controls put in place to minimise the number of people exposed, and workers need to be informed about reproductive hazards and trained in risk control strategies.

Ventilation needs to be adequate for the hazards which may be present, and suitable personal protective equipment should be provided if risks cannot be effectively controlled in other ways. Early notification of pregnancy should be encouraged to ensure adequate care and protection from known reproductive hazards, and in some cases health surveillance programs should be established to monitor exposed individuals for any signs of adverse effects.

Guidance material available
Available guidance includes Reproductive Health and Pregnancy, a factsheet available from the National Occupational Health and Safety Commission, and the Pregnancy and Work Guide 2002 from WorkCover NSW.