Spontaneous abortions and work in day nurseries

420 pregnancies were recorded between 1962 and 1987 among 202 women working for at least one month in day nurseries during 1984. During that time 230 pregnant mothers had worked as childminders in day nurseries ('exposed' pregnancies). The remaining 190 pregnancies were classified as 'unexposed'. 27 spontaneous abortions were exposed and 7 unexposed corresponding to abortion rates of 11.7% and 3.9%, respectively, which is a significant difference. Also 'threatened' abortions during the first trimester of pregnancies ending up in live-born children were accumulated in exposed pregnancies, and the miscarriage rate was possibly increased in unexposed pregnancies of women with their own children in day nurseries. Significant differences were not observed with regard to premature birth, congenital malformations, number of live-born children and sex ratio of live-born children. The cause of the increased frequency of spontaneous and 'threatened' abortions in exposed pregnancies could be a contagious agent.