To identify the drivers of changes in modern contraceptive use (MCU) among women of reproductive age in three selected sub-Saharan African countries.

This is a secondary analysis of cross-sectional Demographic and Health Survey (DHS) data using a multivariable Blinder-Oaxaca decomposition approach.

The sample consisted of 73 777 women aged 15–49 years from the two most recent DHSs conducted in Gabon (2012, 2019–2021), Senegal (2018, 2023), and Tanzania (2015, 2022). Pregnant women were excluded from the sample.

We assessed the change in MCU over the two most recent DHS waves for the three countries.

MCU declined in Gabon from 26.5% to 18.4%, in Senegal from 20.5% to 18.5% and in Tanzania from 29.7% to 27.6%. Across the three countries, the contributions of compositional changes to trends in MCU varied significantly. In Senegal, characteristics explained 181% of the change, driven by reduced exposure to family planning information (157%), high parity (147%) and employment (9%), while education, urbanisation, union type and lower parity mitigated the decline. In Gabon, the overall characteristics included led to an increase in MCU (–44%), rather than a decline, reflecting the effect of favourable changes toward higher education (–19%) and urban residence (–10%). However, the behavioural effect was predominant (144%). This suggests that modifications in individual attitudes, practices and preferences regarding contraception outweighed structural changes, leading to the overall downward trend observed in Gabon. In Tanzania, neither characteristics nor coefficients significantly explained observed changes. Results for Tanzania indicate that none of the factors included in the model made a significant contribution to the change in MCU. Conversely, increases in educational attainment and urbanisation contributed to an increase in MCU in both Senegal and Gabon.

Interventions promoting MCU should consider the role of receiving family planning information at a health facility, parity, work status, educational attainment and urbanisation in informing changes in the use of modern contraceptive methods.