Doppler FHR Detector (BF-500D+, BF-560)

The Doppler FHR Detector (models BF-500D+ and BF-560) is a handheld ultrasound device that detects and displays fetal heart rate and plays fetal heart sound in singleton pregnancies after 12 weeks gestation. It is intended for use by healthcare professionals in hospitals, clinics, community settings, and homes.

Both subject models use continuous-wave Doppler ultrasound at 2 MHz (BF-560 adds 3 MHz option). Key differences from predicate BF-500B include: lower power supply (9V or 4.5V vs 9.6V), reduced acoustic output power, smaller effective radiating areas, shorter working time (≥2 hours vs ≥5 hours), and slightly different FHR measuring ranges (65–210 bpm vs 50–210 bpm). Battery types differ: BF-500D+ uses rechargeable Ni-MH; BF-560 uses alkaline AA batteries.

IEC 60601-1 and IEC 60601-1-2 (electrical safety and EMC); IEC 60601-2-37 (ultrasonic equipment requirements); IEC 62359:2017 and FDA 2019 guidance for acoustic output measurement; ISO 10993-1, 10993-5, and 10993-10 (biocompatibility); FDA 2005 guidance for software documentation.

The subject devices and predicate BF-500B share the same intended use (fetal heart rate detection in singleton pregnancies ≥12 weeks), same device class, regulation, and product code. Although technological parameters differ (power supply, output power, effective area, working time), these differences do not raise new safety or effectiveness questions because all acoustic and safety metrics remain within acceptable limits, and comprehensive bench testing (acoustic output, electrical safety, biocompatibility, software validation, and 609-hour use-life testing) demonstrates the devices perform safely and effectively under their intended conditions.