In a cardiotocographic categorization method, an initial fetal heart rate (FHR) baseline is determined for a cardiotocographic window. The initial FHR baseline is refined for the cardiotocographic window using an iterative refinement process that includes: iteratively identifying FHR accelerations and decelerations in the cardiotocographic window using the FHR baseline； and determining a refined FHR baseline for the cardiotocographic window with the identified FHR accelerations and decelerations excluded. The initial fetal heart rate baseline is replaced with the refined fetal heart rate baseline to repeat the iterative refinement process until a predefined validation criterion is met. A category is assigned for the cardiotocographic window using a cardiotocographic categorization guideline operating on the FHR baseline and the FHR accelerations and decelerations identified in the last repetition of the iterative refinement process. In some embodiments, the FHR baseline determined is based on characteristics of a histogram of FHR values in the cardiotocographic window.
