The electronic fetal monitor senses the heartbeat of the fetus and the mother's contractions during labor. Monitors use Doppler ultrasound transducers, placed on the mother's belly, to emit ultrasound and translate the reflection into audible sound. The authors explore how users listen to this sonification. A literature review revealed only the basics: they listen to fetal heart rate. However, recordings also contain "swooshing" in the uterine environment, the sound of motion relative to the transducer, and other sounds. In their care for mothers and babies, users may be listening to these elements, or getting a tacit sense of the state of the pregnancy from the sound as a whole. To ensure the next generation of fetal monitors capture all that users need to hear, interviews and surveys were conducted with labor and delivery nurses, midwives, and OBGYNs in three countries. Per these engagements, insights were gained regarding: what users listen for beyond the fetal heart rate; how profession and cultural context determines what they listen for; how they were taught to listen (if at all) in their education; the importance of listening versus looking at the monitor; and user preferences for the quality of the Doppler sound -particularly what sounds "clear" versus "real" (and what "real" means for an abstract sonification of inaudible ultrasound).