Maternal obesity is associated with adverse perinatal outcomes and could influence fetal autonomic development. This study aims to evaluate maternal–fetal cardiac coupling (MFCC) in normal-weight and obese women by analyzing mother–fetus RR interval dyads during active labor. Transabdominal recordings from 28 participants (15 with normal weight and 13 with obesity) were processed to extract maternal and fetal electrocardiograms, from which 3-min RR interval segments were selected. Linear and nonlinear coupling methods, including Pearson correlation (r) and mutual information (MI), were applied to quantify the MFCC. Results indicated an overall reduction in cardiac coupling in the obesity group compared to the control group, reflecting altered coordination between maternal and fetal cardiac rhythms. These findings suggest that maternal obesity may alter maternal-fetal cardiac dynamics and interactions, underscoring the potential of MFCC as a potential non-invasive and innocuous biomarker for fetal well-being during labor.