Characteristics of women undergoing induced abortion: results of a case-control study from Northern Italy.

In order to identify subgroups of women at elevated risk of induced abortion, personal characteristics and habits, selected medical histories and contraceptive practices of 873 women undergoing legal abortion in various areas of Northern Italy were compared with those of 504 control subjects identified in family planning clinics of the same hospitals or area health authorities. When age was allowed for, the risk of induced abortion was not strongly influenced by marital status, education or other indicators of social class. However, women who were employed, independently from the type of occupation, showed markedly lower abortion risks than housewives. Among various indicators of sexual habits investigated, the strongest determinant of legal abortion was the frequency of sexual intercourses over the previous six months, women with less frequent intercourses showing a markedly elevated risk estimate (RR = 2.82). Induced abortion was less frequent among ex-smokers and more frequent in heavy smokers, but was not appreciably influenced by several other indicators of lifestyle habits and history of gynaecological or psychiatric complaints. The risk of abortion was not influenced by the number of livebirths, but was lower for women with later age at first birth. Less than 5% of case and control subjects reported more than two previous induced abortions, thus indicating that abortion is more of an "accidental" event rather than a widespread contraceptive practice. However, over three-quarters of abortions occurred in women reporting no contraception at all or coitus interruptus, thus underlining the scope for family planning education in this population.