The authors report and discuss the characteristics of 22 women who discovered their HIV seropositivity while pregnant. Most of the women had never been tested for HIV and this occurred not only for 'not at risk' women but also for sexual partners of HIV-infected men. Several infections were diagnosed late in pregnancy when most women were already immunodeficient. An implementation of HIV prenatal testing as an early standard clinical practice, should be promoted in all women, regardless of the presence of risk factors.