Clinicians managing obstetric patients are dependent on valid hemodynamic measurements to guide care. Heart rate and noninvasive blood pressure guide most current care. New hemodynamic monitors are being used to report research findings and are being investigated by clinicians for their value to supplement standard monitoring. These include arterial pulse contour analysis, Doppler velocimetry, and bioimpedance among others. This chapter serves to present these new devices with a critical review of their advantages and limitations, and most importantly the validity of their measurements.