Self-monitoring of menstrual blood loss volume could lead to early detection of multiple gynecological diseases. In this paper, we describe the development of a textile-based blood volume sensor which can be integrated into the sanitary napkin to quantify the menstrual blood loss during menstruation. It is based on sensing the resistance change detected as the output voltage change, with the added volume of fluid. Benchtop characterization tests with 5 mL of fluid determined the effect of spacing, orientation and weight, and location of fluid drop on the sensor. The sensor has been evaluated by intravenous blood samples collected from 18 participants and menstrual blood samples collected from 10 participants for four months. The collected intravenous blood samples and menstrual blood samples were used to create two regression model that can predict the blood volume and menstrual blood volume from the voltage input with Mean Absolute Percentage Error (MAPE) of 11-15% and 15-30% respectively.