Maternal care facilities in Nigeria play a crucial role in improving maternal health outcomes. However, there is limited empirical evidence on their effectiveness and potential biases. A randomized field trial design was employed to assess the impact of improved maternal care facilities. Participants were randomly assigned to either an intervention group (enhanced care facilities) or a control group (standard care). The study found that the intervention significantly reduced maternal mortality rates by 20%, with a 95% confidence interval indicating a robust effect. This randomized field trial approach provides strong evidence for the efficacy of improved maternal care facilities in Nigeria, offering a clear pathway to reducing maternal mortality. Policy makers should prioritise funding and infrastructure development for enhanced maternal care facilities based on these findings. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.