Does working with video display terminals (VDTs) increase the risk of miscarriage or birth defects?
In the late 1970s, as the use of video display terminals (VDTs) in the workplace became increasingly common, questions arose concerning the potential effects on pregnancy outcomes of working with these terminals. Clusters of miscarriages and birth defects were reported at several workplaces in the United States and Canada (later in this chapter there is a discussion of clusters at the end of this chaper). Various VDT exposures and emissions have been measured: X-rays, ultraviolet radiation, visible light, infrared radiation, radio frequency fields, power-frequency EMFs, chemicals (PCBs), air ions, and static fields. Workers’ exposures to these emissions are very low. However, unlike other office equipment, VDTs emit pulsed electromagnetic fields in the very low frequency (VLF) range, specifically 15,000 to 30,000 Hz (see the Electromagnetic Spectrum). In 1982, a laboratory in Spain reported that malformations occurred in chicken embryos exposed to pulsed magnetic fields at low frequenc
