Causes of short birth interval (kunika) in Bauchi State, Nigeria: systematizing local knowledge with fuzzy cognitive mapping

Background Short birth intervals, defined by the World Health Organization as less than 33 months, may damage the health and wellbeing of children, mothers, and their families. People in northern Nigeria recognise many adverse effects of short birth interval (kunika in the Hausa language) but it remains common. We used fuzzy cognitive mapping to systematize local knowledge of causes of kunika to inform the co-design of culturally safe strategies to address it. Methods Male and female groups in twelve communities built 48 maps of causes and protective factors for kunika, and government officers from the Local Government Area (LGA) and State made four maps. Each map showed causes of kunika or no-kunika, with arrows showing relationships with the outcome and between causes. Participants assigned weights for the perceived strength of relationships between 5 (strongest) and 1 (weakest). We combined maps for each group: men, women, and government officers. Fuzzy transitive closure calculated the maximum influence of each factor on the outcome, taking account of all relationships in the map. To condense the maps, we grouped individual factors into broader categories and calculated the cumulative net influence of each category. We made further summarised maps and presented these to the community mapping groups to review. Results The community maps identified frequent sex, not using modern or traditional contraception, and family dynamics (such as competition between wives) as the most influential causes of kunika. Women identified forced sex and men highlighted lack of awareness about contraception and fear of side effects as important causes of kunika. Lack of male involvement featured in women’s maps of causes and in the maps from LGA and State levels. Maps of protective factors largely mirrored those of the causes. Community groups readily appreciated and approved the summary maps resulting from the analysis. Conclusions The maps showed how kunika results from a complex network of interacting factors, with culture-specific dynamics. Simply promoting contraception alone is unlikely to be enough to reduce kunika. Outputs from transitive closure analysis can be made accessible to ordinary stakeholders, allowing their meaningful participation in interpretation and use of the findings. Plain English summary For people in Bauchi State, northern Nigeria, kunika describes a short interval between successive births, understood as becoming pregnant again before the previous child is weaned. They recognise it is bad for children, mothers and households. We worked with 12 communities in Bauchi to map their knowledge of the causes and protective factors for kunika. Separate groups of men and women built 48 maps, and government officers at local and state level built four maps. Each group drew two maps showing causes of kunika or of no-kunika with arrows showing the links between causes and the outcome. Participants marked the strength of each link with a number (between 5 for the strongest and 1 for the weakest). We combined maps for women, men and government officers. We grouped similar causes together into broader categories. We calculated the overall influence of each category on kunika or no-kunika and produced summary maps to communicate findings. The maps identified the strongest causes of kunika as frequent sex, not using modern or traditional contraception, and family dynamics. Women indicated forced sex as an important cause, but men focused on lack of awareness about contraception and fear of side effects. The maps of protective factors mirrored those of the causes. The groups who created the maps approved the summary maps. The maps showed the complex causes of kunika in Bauchi. Promoting contraception is unlikely to be enough on its own to reduce kunika. The summary maps will help local stakeholders to co-design culturally safe ways of reducing kunika.