ARE COMPUTER SCREENS SAFE FOR PREGNANT WOMEN ?

More than million video display terminals ( VDT ) are now glowing, scanning, taking instructions and solving problems in many offices and homes. They have become indispensable, but are they really safe? The question arises because of persistent worries that video may pose a variety of health risks from cataracts and muscle strain to miscarriages and birth defects. About a dozen unexplained clusters of miscarriages among video users have been reported since 1980, but so far researchers have not been able to confirm a link. Now a study has found that women who used video more than 20 hours a week had almost twice as many miscarriages as women who did other kinds of office work. The authors emphasize that their findings show an association between heavy VDT use and miscarriages but that they're not sure whether the losses resulted from exposure to the equipment or the workplace itself.

The California researchers, led by Marilyn K. Goldhaber, questioned 1,583 women in the San Francisco Bay Area about their pregnancies and their exposure to various environmental hazards during gestation. While all the women who worked in offices had a higher miscarriage rate than those who stayed home, the only significant finding was among administrative and clerical workers. The women in that category who spent more than 20 hours a week in front of a VDT screen had an 80 percent increased risk of miscarriage, compared with workingwomen who didn't use VDT.

Goldhaber and her colleagues, Dr. Robert A. Hiatt and Michael R. Polen, don't think the link they found is the result of radiation exposure. Extensive testing, they say, has virtually eliminated ionizing radiation as a health hazard for VDT users. And if the very low frequency, nonionizing radiation that VDT' also emit were causing miscarriages, the problem would have occurred in all the occupational groups studied. This suggests to us that it's something to do with the occupation, says Hiatt. Maybe it's not conducive to a good pregnancy to be under a lot of deadline pressure, not to have job autonomy and to sit in a cramped position. The findings could also be explained entirely by distorted recollection, says Goldhaber. When women who had miscarried were interviewed, for example, they might have unwittingly overestimated the time they spent in front of a VDT.

Other research teams are also looking at possible links between VDT and pregnancy problems. One at the National Institute for Occupational Safety and Health is investigating miscarriage rates among 4,000 telephone operators, half of whom work in front of VDT while the other half do not. In the realm of comparing jobs in various industries, they are the most similar we could find, says epidemiologist Teresa Schnorr, director of the study. Researchers at New York's Mount Sinai Medical Center are about to launch the first prospective study, they will follow 8,000 female office workers and determine the effect of VDT exposure on those who conceive. Meanwhile, says Goldhaber, women who work with VDT should not be alarmed, but they can take precautions. Pregnant women who use VDT for more than half the working day, she advises, should take frequent breaks, make sure to sit in an unstrained position and intersperse non VDT work with VDT work. Indeed, that's good advice for anyone who works with a VDT.