Objectives: We analyzed the influence of the radioactive fallout after the Chernobyl disaster on the rate and regional distribution of birth defects and abortion rates in southern Austria.
Study design: During 1985 to 1989 a total of 66,743 births was monitored. Twelve sources provided data on 1695 cases of birth defects, 1579 of which were suitable for analysis. All cases were analyzed in terms of their calculated conception date and divided into three main groups according to their vulnerable phase of embryogenesis, spermatogenesis, and oogenesis. To study possible regional changes, the findings were plotted in 17 political subdistricts. The overall abortion rate and the counseling frequency at termination clinics was determined.
Results: No significant changes in the incidence of birth defects, abortion rate, or counseling rate at pregnancy termination clinics were observed.
Conclusions: Assessing the teratologic potential of low-dose radiation is difficult and requires adequate grouping of birth defects, sufficient baseline data, and highly reliable registries.
PIP: Researchers analyzed data on 66,743 births which occurred between 1985-1989 in the Styria region in southern Austria to determine whether radioactive fallout from the meltdown of the nuclear reaction at Chernobyl in the Ukraine, USSR in may 1986 affected the birth defect and abortion rates in this area of Austria. There were 1695 birth defect cases. Of the birth defects which occurred during embryogenesis, most occurred 14-49 days postconception (group 2; n=630). The researchers did not note a short-term effect of the fallout in group 2 or the other groups (relative risk= 0.75, 0.73 for group 1, and 0.93 for group 2). Baseline birth defect rates (per 1000 births) for groups 1, 2, and 3 were 2.5, 8.5, and 1,8 respectively. The only sizable increase occurred in group 2 at years 2 and 3 (10.6 and 10.3, respectively). More reported minor congenital defect cases accounted for this increase due to the newly established data base in the Department of Pediatric Cardiology at the University of Graz. Thus the increase was an artifact and not a true increase. Abortion rates varied from 10% to 14% and did not increase significantly after Chernobyl. Counseling frequency at abortion clinics fluctuated greatly (117-205) both before and after Chernobyl and the changes were not significant. These results indicated that the low dosage of radiation did not have a detectable biologic effect in terms of birth defects and abortions. The researchers addressed the difficulties with measuring teratologic potential of low dose radiation. They also highlighted the need for accurate categorizing of birth defects, adequate baseline data, and very reliable registries. Future research on possible environmental disasters which affect Austria can use these data as baseline data.