Risk of perinatal mortality among the offspring of workers employed at production with radiation hazards

Studies that address risks of perinatal mortality among the offspring of people exposed to ionizing radiation in the workplace are significant for developing hygienic standards at production facilities with radiation hazards. The purpose was to analyze perinatal mortality (stillbirths and early neonatal deaths) among the offspring of workers employed by Mayak Production Association (Mayak PA), the first atomic production facility in Russia. A retrospective analysis was performed among 25,007 children born in 1949-1973; parents of 14,580 of these children were exposed to long-term occupational radiation at Mayak PA. The study provides frequency and dynamics of perinatal mortality and comparative analysis of perinatal mortality by sex, year of birth, parental age at childbirth, and dose categories of radiation exposure. Research data were analyzed by methods of non-parametric statistics. We calculated a relative risk (RR) of perinatal mortality among the offspring of exposed and unexposed parents with 95 % CI. The rate of perinatal mortality was generally the same in both groups, 19.9 for 103 in the test group and 17.9 for 103 in the control, p > 0.05. Stillbirths among male offspring were statistically significantly more often observed in the test group due to contribution of the children with only mothers exposed to occupational radiation exposure at Mayak PA prior to conception and offspring exposed in utero. Intrauterine fetal death was observed statistically significantly more often among boys of the test group compared to controls: 2.9 against 0.9 for 103. Rates of stillbirths and perinatal mortality in the main group statistically significantly exceeded the values in the comparison group in 1949-1953: RR = 2.69 (CI: 1.46-4.95) and 2.12 (1.38-3.28) respectively. Significant statistical differences in the perinatal mortality risk were established in certain categories of preconception and intrauterine gamma-exposure. The identified peculiarities of unfavorable outcomes in the perinatal period that were detected among the offspring of Mayak PA workers could be eligible for further epidemiological monitoring. Poly-etiology character of perinatal mortality requires further follow up of the cohort of the offspring born to atomic production workers.