Maternal care facilities in Nigeria are crucial for maternal health outcomes, yet their effectiveness varies widely. A comprehensive search was conducted using multiple databases and grey literature sources. Studies were critically appraised based on quality criteria including study design, data collection methods, and analysis techniques. The review identified a significant proportion (70%) of studies used linear regression models for forecasting outcomes, with some studies incorporating uncertainty through confidence intervals. This systematic review provides insights into the methodological practices in Nigeria’s maternal care facilities and highlights the need for standardised time-series forecasting methods to enhance clinical outcome predictions. Standardised methodologies should be adopted to ensure consistency in outcomes reporting across different studies, facilitating better resource allocation and policy-making. Treatment effect was estimated with $\text{logit}(p_i)=\beta_0+\beta^\top X_i$, and uncertainty reported using confidence-interval based inference.