arXiv:2610.32682v1 Announce Type: new Abstract: Objective: Fetal magnetocardiography (fMCG) enables early detection of cardiac disease by non-invasively measuring fetal electrophysiological activity. However, current signal estimation methods for fMCG require complex, labor-intensive human processing because they rely on blind source separation or template-based projection techniques. Methods: We propose an automated signal reconstruction approach that recovers fetal and maternal cardiac activity from fMCG measurements without manual annotation. Our approach leverages the relationship between measurements and cardiac signals via a biophysically grounded forward model that represents cardiac sources as time-varying magnetic dipoles. This enables reconstruction of physiologically interpretable three-dimensional vectorcardiographic signals along with their spatial position. Results: Validation on synthetic data with known ground truth confirms accurate recovery of cardiac source parameters. On real fMCG recordings, the reconstruction shows strong agreement with established reference methods. Conclusion: The proposed forward-model approach automatically reconstructs fetal and maternal cardiac activity from fMCG recordings and produces signals in an interpretable vectorcardiographic source domain. Significance: Automated, interpretable fMCG reconstruction could make fetal cardiac assessment more reliable and support potential translation into prenatal care.