Techniques for reducing power consumption by fetal ultrasound transducers are provided. In an example, a fetal sensor device (FSD) comprising a processor, controls operations an ultrasound transducer of the FSD in accordance with a power optimization protocol that results in minimizing power consumption by the FSD, wherein the ultrasound transducer is configured to measure one or more fetal parameters of a fetus using doppler based ultrasound technology, wherein the FSD operates in an active mode that comprises alternating between transmit periods wherein the ultrasound transducer transmits ultrasound signals, and receive periods wherein the ultrasound transducer measures reflected signals of the ultrasound signals that are received by the ultrasound transducer during the receive periods, and wherein the controlling comprises controlling a transmission power of the ultrasound signals and/or a duration of the transmit periods during the active mode in accordance with the power optimization protocol.