Evaluation of the causal effect of maternal education on the utilisation of maternal health services in Bangladesh using an observational study - a comparison of different propensity score methods and covariate adjustment

Abstract Background Assessing maternal health care utilisation is imperative for the health of both mother and her child. Maternal education is an important determinant in subsequent maternal health care usage, according to research. There is a dearth of research on the causal relationship between maternal education and maternal health services as well as examining the performance of different propensity score methods for estimating absolute effects. Therefore, this study aims to estimate the effect of maternal education on usage of maternal health services minimising the confounding effect and to examine the ability of different propensity score approaches to estimate absolute effects of maternal education on usage of maternal health services. Methods We used data from a cross-sectional study conducted by icddr,b in Bangladesh. A total of 1300 recently delivered mothers were included in this study. We used four propensity score methods to estimate the causal effect of maternal education on receiving maternal health services, including propensity score (PS) matching, PS weighting (average treatment effect and average treatment effect among the treated), covariate adjustment using PS, as well as used multiple logistic regression. Results The study revealed highly imbalanced possible confounding factors for mothers' educational level, which might lead to erroneous estimates. All methods indicate a significant effect of maternal education on maternal health services where mothers exposed to secondary or higher levels of education were more likely to have four or more ANC, delivered at facility, PNC within 42 days as well as receiving all maternal health services compared to the mothers who have below secondary level of education. The PS weighting provides better estimates with a low range of confidence interval. Conclusions The results provided important insights on how well these techniques worked to reduce confounding variables and achieve precise estimates. All methods indicated a significant causal effect of maternal education on the usage of maternal health services. However, propensity score weighting method performed better in terms of providing more precise estimates with a narrower range of confidence intervals, indicating that this method may be a reliable approach for estimating the causal effect of maternal education on maternal health service utilisation.