Module 3: Toxicology - Section 18: Reproductive Health Disorders in the Workplace

TOX 18.2 Reproductive Health Hazards

1. REPRODUCTIVE HEALTH HAZARDS AND ADVERSE REPRODUCTIVE HEALTH EFFECTS:

Reproductive health hazards include substances as well as certain conditions in the workplace, which affect the ability of parents to have healthy children, or to have children at all. These hazards can be chemical, physical or biological agents, which can cause reproductive impairment in adults and developmental impairment in the embryo/foetus or child. Exposure to reproductive hazards can result in delay or prevention of pregnancy, termination of pregnancy, decreased physical or mental health of the baby and developmental malformations. The physiological changes in pregnancy can also heighten the effect of certain workplace exposures. In addition, there are many work situations, such as highly stressful jobs or shift work, that may cause negative effects on the reproductive systems of men and women.

The last three decades witnessed an unprecedented interest and concern with regards to the effects of different hazards on human reproduction. During this period scientific evidence made visible a large range of adverse reproductive effects of chemical, physical and biological agents. Recognition of this range of reproductive health problems and the need for prevention has led to a more holistic approach to reproductive outcome. It is now recognised that reproductive hazards can have adverse effects on fertility of men and women, on pre-natal and post-natal development as well as during breastfeeding. The prevention of reproductive disorders, affecting women and men, has therefore become an important consideration in public health. The following tragic reproductive health events alerted and emphasized to the world the central importance of primary prevention:

1.1 Thalidomide:

Thalidomide, prescribed as an anti-emetic and sedative to pregnant women, was linked to limb malformations and other defects in newborns.

1.2 Diethylstilboestrol (DES):

DES is a synthetic oestrogen used to prevent miscarriage. In utero exposure to DES resulted in anomalies of the reproductive tract and later development of vaginal cancer in daughters of women who were treated with DES.

1.3 Methyl mercury, Minimata Bay, Japan:

In this incident fish was contaminated with methyl mercury released from a manufacturing plant. The offspring of pregnant women who consumed the contaminated fish suffered from mental retardation, cerebral palsy, and developmental delay.

1.4 Polychlorinated biphenyl (PCB):

Use of polychlorinated biphenyl (PCB)-contaminated cooking oil in Taiwan resulted in intra-uterine growth retardation and hyper pigmentation of the skin in infants of exposed women. Effects on that cohort continue to be uncovered today, including on offspring pubertal development.

1.5 Dibromochloropropane (DBCP) - California, USA:

In 1977, at a pesticide formulation plant in northern California, male workers with long-term exposure to dibromochloropropane (DBCP) were found to have decreased sperm counts and impaired fertility, which in some never recovered even when exposure was discontinued. Subsequently banana plantation workers in Costa Rica exposed to the same pesticide suffered major fertility problems.

Events such as the above led reproductive toxicologists and epidemiologists to examine a large number of workplace and environmental exposures for potential adverse reproductive and developmental effects in men and women. Sadly, even though some of these hazards have been successfully identified as reproductive toxins, their use have not always been discontinued.

In more recent years, there have been ongoing concerns about the reproductive effects of occupational exposure to solvents, pesticides, and video display terminals or electromagnetic fields. A new major focus of reproductive health research has developed to identify and study chemicals considered to act as endocrine disruptors, affecting both wildlife and humans.

Postgraduate Diploma in Occupational Health (DOH) - Modules 3: Occupational Medicine & Toxicology (Basic) by Profs Mohamed Jeebhay and Rodney Ehrlich, Health Sciences UCT is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License. Major contributors: Mohamed Jeebhay, Rodney Ehrlich, Jonny Myers, Leslie London, Sophie Kisting, Rajen Naidoo, Saloshni Naidoo. Source available from here. For any updates to the material, or more permissions beyond the scope of this license, please email healthoer@uct.ac.za or visit www.healthedu.uct.ac.za. Last updated Jan 2007.
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