Social determinants and socioeconomic inequalities in adherence to antenatal iron-folic acid supplementation in urban and rural Indonesia.

Introduction: Adherence to iron-folic acid supplementation (IFAS) has been linked with maternal anaemia. While findings about determinants of IFAS adherence have been mixed across different research, there is inadequate evidence in relation to socioeconomic inequalities. This study aims to examine social determinants and socioeconomic inequalities of adherence to IFAS in urban and rural Indonesia.

Methods: We conducted a secondary analysis of the 2017 Indonesia Demographic and Health Survey by including a total of 12 455 women aged 15-49 years. The outcome was adherence to IFAS for at least 90 days. We used multiple logistic regression analysis adjusted for the survey design to analyse factors associated with IFAS adherence. We estimated socioeconomic inequalities using the Wagstaff normalized concentration index and plotted them using the concentration curve.

Results: About half of women consumed IFAS for at least 90 days, with a higher proportion in urban areas (59.0%) than in rural areas (47.8%). Social determinants of adherence to IFAS were similar for urban and rural women. Overall, being an older woman, having weekly internet access, antenatal care for at least four visits, and residing in Java and Bali were significantly linked to IFAS adherence. Higher maternal education was significantly linked to IFAS adherence in urban settings, but not in rural settings. There were interactions between place of residence and woman's education (p<0.001) and household wealth (p<0.001). Concentration indices by woman's education and household wealth were 0.102 (p<0.001) and 0.133 (p<0.001), respectively, indicating pro-educated and pro-rich inequalities. However, no significant education-related disparity was found among rural women (p=0.126).

Conclusion: Women (age, education, occupation, birth number, internet access, involvement in decision-making), household (husband's education, household wealth), health care (antenatal care visit) and community (place of residence, geographic region) factors are associated with overall adherence to IFAS. These factors influence the adherence to IFAS in a complex web of deep-seated socioeconomic inequalities. Thus, programs and interventions to improve adherence to IFAS should target women of reproductive age and their families, particularly those from socioeconomically disadvantaged groups residing in rural areas.