Prenatal monitoring with wearable devices to investigate associations between gestational diabetes, fetal sleep, and autonomic regulation

Diabetes during pregnancy, including type 1, type 2, and gestational diabetes, affects over 8% of pregnancies in the US and approximately 16% globally. The altered metabolic environment can disrupt fetal developmental trajectories and affect neurodevelopmental outcomes. Growing evidence indicates that maternal diabetes shapes the organization of fetal behavioral states, which emerge mid-gestation and reflect central nervous system maturation. Here, we examine fetal sleep physiology in a naturalistic setting using overnight abdominal fetal ECG (fECG) collected at home between 34 and 37 weeks of gestation. The sample included 26 fetuses exposed to diabetes and 12 healthy controls. Fetal heart rate (HR) and measures of heart rate variability (SDNN, RMSSD, sample entropy) were extracted and coded for fetal states; active (AS) or quiet sleep (QS). Results showed significant main effects of fetal state ( p <.001) and diabetic status ( p =.023) on HR. Participants with diabetes exhibited higher fetal HR, particularly during QS ( p =.006). SDNN varied by state ( p <.001) and sample entropy showed a state by exposure interaction ( p =.048). Diabetic-exposed fetuses spent less time in AS and more time in QS ( p <.001). Findings indicate that prenatal exposure to diabetes may explain differences in fetal autonomic regulation and behavioral states organization. Prenatal wearable monitoring of fetal behavior offers novel insights into neurobiological pathways underlying altered intrauterine environments.