Spontaneous abortion among women using video display terminals.

This case-base study with a source population of 214 108 commercial and clerical workers investigated the risk of adverse pregnancy outcome among women working with a video display terminal (VDT) in Denmark. A subpopulation was obtained by register linkage between a trade union membership file, the Medical Birth Register, and the National Register of In-Patients. In two years 24,352 pregnancy outcomes were registered, 2248 spontaneous abortions were recorded, and a base sample of 2252 pregnancies was randomly selected. Data on VDT use, job stress, ergonomic factors, and life-style factors were collected with questionnaires sent to 6212 women and 426 employers. There was no increased risk of medically verified spontaneous abortion among women with VDT use. The relative risk for women exposed to any degree of use was 0.94 (95% confidence interval 0.77-1.14). Ergonomic work load and job stress were not confounders.