A controlled comparison study was completed using interview data from 80 women each experiencing their first pregnancy whilst single. Half of the women continued their pregnancy, in some cases marrying the father. The other half obtained an abortion. Two interviewers, one male and the other female, each completed an equal number of interviews with both groups of women.

The women selected for the study had the following traits: (1) never married before this, their first conception; (2) aged 17–30 years; (3) white ethnic status; (4) had not delivered or terminated the pregnancy at the time of the interview. The sample consisted of volunteers from the ante-natal and gynaecology clinics at St Mary's Hospital Medical School and Samaritan Hospital for Women, London, W.2, and Kingston and Richmond Hospitals, Surrey.

Almost all topics examined in the pre-conception period turned out to be characteristic of women experiencing their first illegitimate conception, whether or not they continued the pregnancy. A detailed examination of contraceptive background revealed no significant differences between the two groups of women, with two exceptions. Women having abortions were more likely, at the time before they conceived, to have accepted the idea of using contraception. A small number of these women were also more likely to have made an effort to obtain a clinical contraceptive device.

The only other pre-conception factor found to be associated with abortion involved the relationship with the father up to the time of conception. If that relationship was uncertain, less meaningful than previous ones, or a social rather than a romantic one, the woman was more likely to terminate the pregnancy.

In contrast to the pre-conception period, almost all analyses of events subsequent to conception revealed differences between the two groups of women. Both concern over being discredited by other people and concealing information about the pregnancy were traits associated with having an abortion, but in a qualitative rather than an absolute sense. These aspects of social stigma were common to all women before the first pregnancy test, but became more evident amongst women having abortions once the pregnancy had been clinically confirmed. Both concern over being discredited and concealing the pregnancy were experienced in relation to particular persons. For women terminating their pregnancies these were usually their parents.

The degree of acceptability of abortion and unmarried motherhood differed between the groups, but they were similar in their views on the acceptability of marriage with pregnancy and adoption. These four alternatives were further examined in terms of the women's preferences and here the two groups differed.

Finally, there were differences between the groups in the effect of the pregnancy on the relationship with the putative father. Women having abortions were more likely to find themselves in a relationship that had either finished or was likely to finish after the father knew of the pregnancy. Some were pregnant by a social acquaintance which precluded either marriage or joint parenthood.

The findings are discussed in terms of the relationship between contraception and abortion for the single woman and consideration is given to the implications for fertility research and contraceptive and pregnancy services.