Fetal heart distance and gestational age significantly influenced OPM-fMCG signal quality, with multivariable models explaining 19.8% of the variance in signal-to-noise ratio.
Observational (n=32)
Do maternal and fetal parameters influence the signal-to-noise ratio and cardiac time-interval detectability in OPM-based fetal magnetocardiography recordings in pregnant women?
Fetal heart distance and gestational age are the primary determinants of OPM-fMCG signal quality, highlighting the need to account for maternal physiological variability to optimize acquisition.
Effect estimate: R2 19.8%
Background Fetal magnetocardiography (fMCG) noninvasively measures the magnetic fields generated by the fetal heart to assess cardiac electrophysiology. The advent of optically pumped magnetometers (OPMs) enables portable, cryogen-free acquisition of high-fidelity fMCG signals. However, maternal and fetal characteristics may introduce variability affecting signal quality and cardiac time-interval (CTI) detectability. Objective This study quantifies the influence of maternal and fetal parameters (placental position, body mass index (BMI), fetal heart distance, and gestational age (GA)) on the signal-to-noise ratio (SNR) and CTI detectability in OPM-based fMCG recordings. Methods A total of 107 OPM recordings were obtained longitudinally from 32 pregnant participants (28-38 weeks of gestation) using a bed-based, stand-alone OPM array system. SNR was derived from fMCG signals, and maternal and fetal characteristics were obtained from clinical data. Mixed-effects linear and logistic regression models were used to evaluate associations between these parameters, SNR and CTI detectability. Results Mean SNR and variance were 10.95 dB and 14.56 dB 2 , respectively. Multivariable mixed-effects linear regression reduced total variance to 12.55 dB 2 and yielded a fixed-effects R 2 of 19.8%. SNR increased significantly with GA and decreased with fetal heart distance. Higher SNR was associated with improved CTI detectability, particularly for T wave and QT interval. GA remained a significant predictor of T-wave detectability, while fetal heart distance exerted an independent negative effect. Conclusion Fetal heart distance and GA are the primary determinants of OPM-fMCG signal quality. Accounting for maternal physiological variability is essential for optimizing acquisition protocols and improving the interpretability of fetal cardiac data.
Ramírez et al. (Mon,) conducted a observational in Pregnancy (n=32). Maternal and fetal parameters (gestational age, fetal heart distance, BMI, placental position) was evaluated on Signal-to-noise ratio (SNR) and cardiac time-interval (CTI) detectability (R2 19.8%). Fetal heart distance and gestational age significantly influenced OPM-fMCG signal quality, with multivariable models explaining 19.8% of the variance in signal-to-noise ratio.