Spontaneous abortion in Italy: social differences and temporal trends.

Spontaneus abortion in Italy between 1980 and 1993 has been analysed with particular reference to temporal trends and to indicators of social status ( level of education and occupation of the women). Each year about 50000 spontaneous abortions are notified in Italy and the trend is slightly increasing. The national rate passed from 8 to 9 spontaneous abortions per 100 conceptions during the period 1983-93. Geographically, the rate decreases from North to South (respectively from 11-12 to 6-8 spontaneous abortions per 100 known conceptions in 1993). The national rate of spontaneous abortion is slightly higher for women with little or no education: 9.0 per 100 known conceptions for women with no or primary school certificate (schooling from 6 to 10 years), 8.8 for those with lower school certificate (ages: 11 to 13 years) 7.8 for high school certificate (ages 14 to 18 years) and 8.3 for university degree, in 1991. There were no significant differences between occupations, excepting agricultural workers who had the lowest rate: 4.1 per 100 known conceptions compared with 8.2 for women employed in industry, 9.3 for other occupations and 8.9 for housewives, students or the unemployed, in 1991. However, maternal age is confirmed to be a more important risk factor: the risk of spontaneous abortion increased from 6-7 per 100 known conceptions among women aged less than 30 to 20 per 100 among women aged 40 or more. The same effects are found in a logistic regression model.