Preliminary evaluation of the impact of the Chernobyl radiological contamination on the frequency of central nervous system malformations in 18 regions of Europe. The EUROCAT Working Group.

The teratological impact of radiological contamination from the Chernobyl accident was evaluated in relation to central nervous system and eye defects in 18 regional registries in nine countries of Western Europe. Six classes of anomaly were analysed: neural tube defects, arhinencephaly, microcephaly and brain reduction, hydrocephaly, anophthalmos and microphthalmos, and congenital cataract. Conceptions up to 31 August 1986 were grouped into two exposure cohorts. In cohort A the sensitive period of fetal development to radiation fell wholly or partly between 1 May and 30 June 1986. Cohort B included all cases exposed during their sensitive period on or after 1 May 1986. Observed frequencies of the six classes of anomaly in the exposed cohorts were compared with expected frequencies calculated from baseline rates for the period 1980-1985. The only significant increase was neural tube defects in Odense, Denmark (four cases observed in cohort A where 0.9 were expected). The results of the study do not show a general increase in the frequency of malformations in the countries of Western Europe. The evidence presented indicates that, in the regions studied, termination of pregnancies or invasive prenatal diagnostic examinations were not justified for women exposed during pregnancy.