Electrohysterography for Uterine Contractility Monitoring: Measurement Principles, Clinical Evidence, and Reporting...

Reliable monitoring of uterine contractility underpins the assessment of labor, the diagnosis of preterm labor, and the timing of obstetric intervention, yet routine methods measure only the mechanical consequences of contraction. External tocodynamometry and cardiotocography (CTG) are operator- and position-dependent and perform poorly with maternal obesity, detecting as few as ~54% of the contractions confirmed by an intrauterine pressure catheter, whereas surface electrohysterography (EHG) detects upward of ~94% by recording the myometrial electrical activity that drives contraction. This review examines EHG and uterine electromyography (EMG) as measurement modalities, covering their physiological origin, acquisition hardware, signal characteristics, feature extraction, and machine-learning analysis, and compares them with CTG against the intrauterine pressure catheter reference standard. Electrical approaches additionally yield predictive parameters, notably spectral peak frequency and propagation velocity, that mechanical methods cannot provide. The principal barrier to translation is methodological heterogeneity rather than physiology: differences in electrodes, filtering, feature definitions, and outcome measures preclude cross-study comparison and meta-analysis. As its central contribution, this review consolidates prior calls for standardization into a minimum reporting set for EHG studies and appraises translational readiness, identifying prospective external validation, shared datasets, explainable models, and outcome-linked trials as priorities.