Burundi, which intends to reduce its fertility from 5.5 to 3 children per woman, has seen the level of intention to use modern contraception decreasing from 66% to 53% between 2010 and 2016-2017. The aim of this study is therefore to explore the social considerations leading to non-intention to use modern contraception among women in union in Burundi. The study proceeds by thematic analysis of the content of the transcripts of 10 focus group discussions conducted in 5 provinces of the country. The results of the analysis show that these include side-effects experienced or feared, the absence of side-effect treatment services, the failure of some methods to prevent pregnancy, and religious opinions. In terms of social interactions, these include religious influences, myths and rumors, and the effects of social cohabitation. Women’s inability to self-determine their contraceptive decisions is also important. These results show that the socio-cultural influence of the community dominates women’s intention to use modern contraception, where the supply of family planning services does not attract users, due to a lack of side-effect treatment. To break down socio-cultural resistance, subsequent interventions would tend to reinsure potential clients of family planning services of the availability of the side-effect treatment package.