Spontaneous abortions by occupation and social class in Finland.

A hospital discharge registry covering all general hospitals in Finland was used in the study of spontaneous abortions. Spontaneous abortions were analysed by the women's occupation and socio-economic class for 1973-75 inclusive. The risk of spontaneous abortion increased from social class 1 to 4 by about 50%. The occupational groups with an increased frequency of spontaneous abortions included industrial and construction work, agriculture, forestry and fishing, sales, transport and communication, services, and students and trainees. Decreased frequency of spontaneous abortions was noted among housewives, and in managerial and clerical occupations. The results suggest that socio-economic factors contribute to the rate of spontaneous abortions analogous to their known adverse effects on pre-term birth, birth weight and perinatal mortality.