This study aimed to elucidate the social and behavioral factors and public health system characteristics that influenced pregnant women's adherence to prenatal care. Forty women diagnosed as HIV-positive by rapid test at delivery were included. Socioeconomic data were collected and a semi-structured interview was conducted. Eight women had > 6 prenatal visits and 12 had no visits. Interviews were submitted to qualitative content analysis. The themes fit into two blocks: those seen as hindering adherence, like unwanted pregnancy, lack of family support, prior knowledge of serological status, adverse social context, negative experiences with prenatal care, and disbelief towards prenatal care, and those facilitating adherence, like family support, valuing healthcare, wanting a tubal ligation, receptiveness by the healthcare team, and positive previous experience with prenatal care. Improving our understanding of the socio-cultural context should help promote strategies to reach such women and include them in better quality care.