Fetal heart rate monitoring

An ultrasound fetal heart rate monitoring system, comprising:

• a sensor interface for obtaining sensor data from an ultrasound probe to be placed on a maternal abdomen;
• a data interface for accessing model data representing a trained object detection model, wherein the object detection model is configured to localize a fetal heart in an ultrasound image;
• a processor subsystem configured to:
• operate the ultrasound probe in an imaging mode to obtain an ultrasound image from the ultrasound probe;
• apply the object detection model to the ultrasound image to determine whether a fetal heart is located in a target region of the ultrasound image detectable by a Doppler mode of the ultrasound probe;
• when the fetal heart is located outside of the target region:
• determine guidance information for guiding the ultrasound probe to an estimated position of the fetal heart from located positions of one or more fetal body parts localized by the object detection model, and to output determined guidance information to a display;
• when a fetal spine is detected and a fetal head is not detected, determine guidance information for guiding the ultrasound probe to an expected location of the fetal head, and/or when the fetal spine and the fetal head are detected, determine guidance information for guiding the ultrasound probe to an expected location of the fetal heart;
• and
• when the fetal heart is located in the target region:
• switch the ultrasound probe to the Doppler mode;
• obtain a Doppler ultrasound signal from the ultrasound probe;
• and compute a fetal heart rate from the Doppler ultrasound signal.