A Doppler fetal monitor provides information about the fetus similar to the information a fetal stethoscope provides. One advantage of the Doppler fetal monitor over an acoustic (not electronic) fetal stethoscope is the audio output, which allows people other than the user to listen to the heartbeat. One disadvantage is the greater complexity and cost, and lower reliability, of an electronic device.
Originally intended for use by health care professionals, this device is becoming popular for personal use.
The fetal heart begins to beat at approximately the same rate as the mothers, which is 80 to 85 bpm. Below illustrates the approximate fetal heart rate for weeks 5 to 9, assuming a starting rate of 80
Week 5 starts at 80 and ends at 103 bpm
Week 6 starts at 103 and ends at 126 bpm
Week 7 starts at 126 and ends at 149 bpm
Week 8 starts at 149 and ends at 172 bpm
At week 9 the fetal heartbeat tends to beat within a range of 155 to 195 bpm.
1) Manufacturer - popular manufactures are Huntleigh, LifeDop, Stork Radio, and Nicolette
2) Probe type - waterproof or not. Waterproof probes are essential for water births.
3) Megahertz frequency - 2 or 3 megahertz probes. Most women can find the heart rate with either 2 or 3 megahertz probes. A 2 megahertz probe is recommended to detect a heart rate in early pregnancy (8-10 weeks), A 3 megahertz probe is recommended for women who are plus sized and pregnant.
4) Heartrate Display - some dopplers automatically display the heart rate, for others the fetal heart rate must be manually counted.