Workplace VDT Use Not a Risk Factor for Reduced Birth Weight, Premature Birth, NIOSH Finds

Contact: Fred Blosser (202) 260-8519
January 7, 1998

Working with video display terminals (VDTs) does not increase a woman's risk of delivering a baby of reduced birth weight or delivering prematurely, the National Institute for Occupational Safety and Health (NIOSH) found in a new report.

The report, published in the December 1997 American Journal of Industrial Medicine, concludes one of the most extensive investigations ever of reproductive health concerns associated with VDT use. Results of the first part of the study, published in 1991, found no association between VDT use and increased risk of spontaneous abortion.

"NIOSH's landmark findings have helped alleviate many concerns and uncertainties once raised about working with VDTs," said NIOSH Director Linda Rosenstock, M.D., M.P.H. "These new data provide additional reassurance to working women, employers, and VDT manufacturers that VDTs do not pose a reproductive risk."

The researchers interviewed 2,430 women employed as telephone operators. During the period covered by the study (December 1983 through January 1986), 707 pregnancies had occurred in which the mothers had been employed at least one day as operators, and in which the pregnancy ended with a live birth. Some 304 of the pregnancies were among operators who had worked with VDTs, and 403 were among women who had not.

Some 27 babies of reduced birth weight were delivered by women who had worked with VDTs, or 8.9 percent of the VDT group, compared with 39 delivered by those who had not worked with VDTs, or 9.7 percent of that group. No substantial differences were seen between the two groups in the mean birth weight of babies by gestational age. Risk factors for reduced birth weight did not include VDTs but did include factors that have been found by other researchers in previous studies: for example, if the infant had been born prematurely; if the mother had smoked, had been on medication for hypertension, had diabetes or thyroid problems, or had a previous baby of reduced birth weight; if the mother was other than Caucasian; if this was a first pregnancy; or if the duration between the mother's pregnancies had been less than 12 months.

Some 24 preterm infants were born to women who worked with VDTs, or 7.9 percent of the VDT group, compared with 45 to those who had not worked with VDTs, or 11.2 percent of that group. Risk factors for preterm birth did not include VDTs but again included factors previously found by other researchers: toxemia, diabetes, and delivery of a prior preterm baby.

The study defined preterm birth as a live birth of 21-37 weeks gestation. A full-term birth is 40 weeks. Reduced birth weight was defined as 2,800 grams (six pounds, three ounces) or less.

For further information about the study or other research on reproductive health issues, contact the toll-free NIOSH information number, 1-800-35-NIOSH (1-800-356-4674).