Abstract

Postpartum hemorrhage (PPH) is the leading and most preventable cause of maternal mortality, particularly in low-resource settings. PPH is currently diagnosed through visual estimation of blood loss or monitoring of vital signs. Visual assessment routinely underestimates blood loss beyond the point of clinical intervention. To address this challenge, we present a novel wearable sensor for peripheral vascular compensation (PVC) that detects changes in cutaneous perfusion using near-infrared photoplethysmography. In a swine model of hemorrhage, the PVC sensor detected significant changes in pulse amplitude and derived compensation index during progressive blood loss and transfusion. The device offers a non-invasive, real-time approach for early hemorrhage detection, potentially improving maternal outcomes globally.