Following a vertical transmission pattern, the prevalence of AIDS among the women of Quebec means a certain percentage of AIDS cases among children; 27 of the 33 cases (82 percent) of children infected by vertical transmission in Canada are from Quebec. Quebec is thus facing a major problem in terms of heterosexual and vertical transmission of the HIV infection which underlines the importance of trying to define the infection rate among women of childbearing age. The Quebec study: "HIV seroprevalence study of women of childbearing age" records the anti-HIV serum profile of women at delivery in Quebec. This study offers complete anonymity, and the results are not linked to any personal indicators. There are two types of voluntary infertility situations which can modify the results of the study, namely an education program which encourages the seropositive woman to practice a safe form of birth control, and the significant increase in the number of interruptions of pregnancy by seropositive women. The results of this study which will take place over a period of two years will be essential for the planning of prevention programs to counteract heterosexual and vertical transmission. 11 notes.