I'm debating whether or not to just wait until we can use fetoscope with the next one. (drmomma.org)
With strong contractions it is very difficult indeed, even with a Doppler sometimes and certainly with a Pinard fetoscope, to hear the FHR. (skepticalob.com)
Fetal heartbeat, either by Doppler at 9 — 12 weeks, or by fetoscope at 16 — 20 weeks, is also positive proof of pregnancy. (doctor-info.website)