The strength of health systems predict access to medicines that prevent death from pregnancy related complications (essential maternal health medicines). But little is known about the relative impact of each health system building block on access. This quantitative cross-sectional study applied Ishikawa model to examine the relative effect of health systems governance, facilities, service delivery, financing and medicine procurement and distribution (independent variables), on availability, affordability and accessibility (dependent variables) of maternal health medicines in resource poor settings. Data analyzed was pulled from 37 WHO pharmaceutical country profiles and USAID MCHIP survey that assessed national programs for the prevention and management of Postpartum hemorrhage and Pre-Eclampsia/Eclampsia. Data analysis included bivariate and multivariate logistic regressions. All independent variables, except for quality of health services showed statistically significant association with access to maternal health medicines and achieved a p-value < .05 in bivariate analysis. Only three predictors however explained 27% of the variance (R2 =.266, F(5,162)=13.12, p<.01). The strength of medicine procurement and distribution systems significantly predicted access to essential maternal health medicines (β= -.41, p<.001), as did robustness of health system financing (β= -.51, p<.001), and quality of health facilities (β= -.34, p<.05). Authorities may prioritize investments in quality improvement, supply chain strengthening programs, and incentives for private sector financing and public-private partnerships for health system strengthening. This study contributes to positive social change by identifying key health system considerations that can inform future efforts to close geographical gaps in MCH outcomes.