Workplace factors such as strenuous physical exertion and exposure to chemicals, infectious agents and stress can pose health risks to a pregnant woman and her developing fetus. Preconception exposures in both men (through sperm) and women (through ova) can affect the offspring. Physicians who may be asked to assess the risk of workplace exposure need skills to identify and quantify an exposure and to synthesize the information into an estimated risk. Feinberg and Kelley review employment issues related to pregnancy and provide an approach to identifying risk factors for pregnant workers.

The occupational and environmental history should include descriptions of past and current jobs along with exposures to chemicals (smoke, vapors or dust), infectious agents (viruses), physical elements (exertion, heat, lifting, noise or irradiation) and psychologic features (stress). Personal protection measures (such as the use of respirators, gloves or masks) and workplace controls (such as ventilation systems) should be considered. Community and home exposures must also be included.

When evaluating a pregnant woman for work-related risks, areas of concern include exposure to chemicals and heavy metals, physical exertion and stress, exposure to infectious agents, radiation and electromagnetic materials. Many chemicals are associated with adverse pregnancy outcomes such as spontaneous abortions, low birth weight, congenital anomalies and impaired cognitive development. Although important data about chemicals and adverse outcomes may be difficult to obtain, employees can ask for copies of the “Material Safety and Data Sheet” from the employer; companies are required to provide this information. The physician can also contact the appropriate state agency. Interventions may include temporarily changing jobs, reducing the use of hazardous materials or using personal protective equipment.

The American Medical Association's Council of Scientific Affairs has developed guidelines for physical activity and continuation of work during pregnancy. These guidelines assume that the woman is healthy and the pregnancy is uncomplicated. Individualized evaluation of a pregnant worker is essential. Physicians should intervene when a pregnant worker's level of physical activity is excessive. Modification of physical exertion may include special safety training, lighter duty, reduced hours or a temporary job reassignment. Infectious exposures are common, especially among health care, school and institutional workers. Cytomegalovirus, parvovirus, rubella and varicella are the more common viruses that pose a risk to the fetus through maternal transmission. Pregnant workers should be advised to take appropriate precautions such as a transfer to another position or a temporary leave from work if harmful exposure is identified.

Pregnant women should avoid exposure to ionizing radiation and radioactive materials because of the risks of mental deficiency and malignancies in the newborn. Alternative work assignments or adequate protective measures are essential to prevent fetal exposure. Work-place stress and occupational fatigue may cause an increased incidence of preterm birth. Physicians may need to counsel patients on stress reduction and management.

The authors conclude that physicians need to be aware of the possible reproductive risks of pregnant workers in their practices and must be able to identify and quantify these risks and provide appropriate counseling for these patients. Resources for up-to-date information on hazardous exposures in the workplace are listed in the accompanying table. The use of consultants is appropriate in more complex cases.