Medical Invention- Fetal Heart Monitor

• The first non-invasive fetal heart monitor was invented in the 1960's by Prof. K. Hammacher and Hewlett Packard. The research took place in Boeblingen, Germany and the first HP-8020-A fetal monitor was distributed to customers in the Spring of 1968. The monitors helped babies by detecting fetal distress during labor.
• Hammacher's invention (U.S. Pat. No. 3,318,303) measures heart sounds by use of a contact microphone and provides outputs distinguishing the first and second heart sounds of each heart cycle by generating impulses coincident with each heart sound. While the first and second heart sounds are distinguished and separately analyzed, the first and second heart sounds are not differentiated by the timing relationships between the heart sounds in the overall heart cycle but merely by the state of a flip-flop which changes state upon the detection of each heart sound to thereby output two series of pulses, one for each heart sound in each heart cycle.
• With the invention of the stethoscope in 1810, physicians could hear the fetal heart beat. However, the instrument could not detect subtle changes or provide continuous surveillance. These deficiencies were overcome in 1968 with the development of electronic fetal monitoring.