Changes in unmet need for family planning among married women of reproductive age in Nigeria: A multilevel analysis of a ten-year DHS wave

Introduction Unmet need for family planning [UNFP] remains a serious public health concern in Nigeria. Evidence suggests that UNFP remains high over the last fifteen years despite numerous policies and programmes aimed at generating demand for family planning. This study used three Demographic and Health Survey (DHS) conducted over a ten-year period (2008-2018) to assess the changes in unmet need for family planning and associated contextual determinants. Understanding changes in unmet need for family planning among women and its associated contextual factors is crucial for designing appropriate interventions. Methods We analysed datasets the Nigeria Demographic and Health Surveys of 2008, 2013 and 2018 to assess changes and contextual determinants of unmet need for family planning. Data were analysed using frequency distribution, chi-square statistical test and multilevel binary logistic regression models. Due to the hierarchical structure of the data in which individuals are nested within households, multilevel mixed-effect logistic regression models were constructed. We used a multilevel binary logistic regression model after adjusting for variables not significant at the bivariate level. An adjusted odds ratio with 95% confidence interval was reported, with a p-value less than 0.05 declared to be significant predictors of unmet need for family planning. Results Unmet need for family planning decreased from 20.21% to 16.10% between 2008 and 2013 but subsequently rose later from 16.10% to 18.89% between 2013 and 2018. The pattern of changes in unmet need for either limiting or spacing was consistently high over the 10-year period, with the highest rate of each of the indicators of unmet need for family planning occurring in 2018 while the lowest rate was in 2008, thus indicating an increase in the proportion of respondents having unmet need for family planning over the referenced period. Age of respondents, educational level, wealth status, religious affiliation, parity, sex of head of household, partner educational level, region of residence, and community socioeconomic status were significant factors associated with the unmet need for family planning across the different data waves in Nigeria (p < 0.05). An intraclass correlation (ICC) of 4.9% showed that the individual and household level factors had a greater influence on the variation in the unmet need for family planning than did community factors in Nigeria. Conclusion The overall prevalence of unmet need for family planning was consistently high over the ten-year period and community-level factors had lowest influence on the variation in unmet need for family planning compared to household and individual-level factors in Nigeria. Policies and interventions should focus on improving women's socio-economic and demographic characteristics at individual, household, and community levels to improve unmet need for family planning.