Birth defects and exposure to video display terminals during pregnancy. A Finnish case-referent study.

Abstract

KURPPA K, HOLMBERG PC, RANTALA K, NURMINEN T, SAXEN L. Birth defects and exposure to video display terminalsduring pregnancy: A Finnishcase-referentstudy. Scand J Work Environ Health II (1985) 353-356. In a test of the widelypublicizedallegation that exposure to video display terminals causes birth defects, interview forms of mothers of I 475 children reported consecutivel y to the Finnish Register of CongenitalMalformationsto have defectsof the central nervoussystem,orofacial clefts, skeletal defects, or cardiovascularmalformations and the forms of the same number of their paired referents were studied. The scrutiny revealed490 mothers with occupational titles indicating potential exposure to video display terminals. Of the 490, 235 were case mothers and 255 were referents. Then, unaware of the casereferent status, three members of the research team perused the mothers' interview descriptions of workday activities for information indicating exposure to video display terminals. Work with such terminals during the first trimester of pregnancy was ascertained for III mothers. Of these, 51 were case mothers and 60 were referents. The comparison of the mothers exposed to video display terminals during the first trimester with those not exposed at all showed a crude odds-ratio point estimate of 0.9 with 95 % confidence limits of 0.6 and 1.2. Adjustment for potential confounders by multivariate logistic regression methods did not materially affect the risk estimates. The results did not indicate a teratogenic risk for operators of video display terminals.

Measurements of extremely low-frequency magnetic fields around video display terminals.

“…Several recent epidemiologic studies suggest that work with a VDT has no adverse effects on pregnancy outcome (24). In a case-referent study of 2 950 mothers, no association between VDT exposure and birth defects was found (14) . Neither did the results of two Swedish investigations suggest a teratogenetic risk for VDT operators (6,12).…”

Congenital malformations among children of women working with video display terminals.

“…It is a posterior finding based on small numbers. Kurppa et al (2) and Ericson & Kallen (3) found an increasedOR for cardiac defects, although statistically nonsignificant. This finding was not confirmed in our study.…”

“…Kurppa et al (2) found an odds ratio (OR) of 0.9 for all malformations (controlled for confounders) and an OR of 1.6 for cardiac defects. Both results were statistically nonsignificant.…”

Effects of low-frequency magnetic fields on embryonic development and pregnancy.

“…Some authors (52,53), but not all (50), have found evidence for recall bias in their data. No increased risks were observed when exposure was assessed by means not affected by recall bias (54,55). The results ofa recent case-base study did not support an association between the use of video display terminals and congenital malformations (56) or spontaneous abortion (57).…”