Among women, adverse effects of exposure include spontaneous abortion, congenital anomalies, fetal growth restriction, gestational hypertension, and preterm birth.
Difficulty in achieving a successful pregnancy is fairly common. About 7% of women aged 15–44 in the United States report that they suffer from fertility problems. Assisted reproductive technologies such as in vitro fertilization are used to conceive 1% of births in the United States, and the rate of use of these technologies is similar or higher in Western Europe.
Some studies have found steady worsening trends in semen parameters, urogenital tract anomalies and testicular cancer. Although other studies have not found such trends, the positive studies have raised concerns that environmental exposures may be affecting reproductive health. Confounding by increasing rates of obesity among men and prenatal exposure of male infants to tobacco smoke are alternate or complimentary explanations for observed trends in semen parameters. When male infertility is diagnosed in clinical settings, non-toxicological explanations such as varicocele, post-pubertal viral infections such as mumps, cryptorchidism and other medical conditions are more common than etiologies related to chemical exposures. Heavy exposure to persistent organochlorine pollutants such as dichloro-diphenyl-trichloroethane (DDT) and polychlorinated biphenyls (PCB), however, can affect male fertility; occupational exposure to certain pesticides such as dibromochloroethane (DBCP) or certain other agents can also impair male fertility.
In women, tubal disorders, polycystic ovary syndrome, ovarian dysfunction related to aging and uterine factors such as leiomyoma are more frequently implicated in the etiology of infertility than toxic exposures. The risk for fertility problems can be increased by handling antineoplastic drugs and organic solvents such as n-hexane, methyl ethyl ketone, ethyl acetate and dichloromethane (also known as methylene chloride) without using optimal equipment and work practices. Exposure to a variety of pesticides have also been associated with prolonged time to pregnancy.
When infants are followed-up into childhood, certain prenatal exposures are associated with neurobehavioral effects. Laboratory animal studies confirm the biologic plausibility of these associations and also have documented trans placental carcinogenesis and fetal immune system changes. Health effects from maternal exposure have been linked to certain heavy metals, organic solvents, pesticides, and pharmaceuticals such as antineoplastic and antiviral agents. Hazardous maternal exposures also include certain biologic agents, radiation, and ergonomic stressors such as prolonged standing, long working hours, and excessive shift work. The rate of adverse reproductive effects is dose-dependent. Clues from the occupational history that substantial internal exposure may be occurring include frequent use of large quantities of the agent, and work practices that promote inhalational or dermal exposure, as well as contamination of food or drink. Personal protective equipment may fail, giving a false sense of security. Counseling can assist the couple to ascertain the level of risk, put their risk from occupational and environmental exposures into perspective and find ways to reduce exposures when warranted.
Frazier, L, Glob. libr. women's med.,
(ISSN: 1756-2228) 2008; DOI 10.3843/GLOWM.10100