The detection and counting of the early fetal heart with Doppler ultrasound.
D000293:Adolescent; D000328:Adult; D005069:Evaluation Studies as Topic; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D005865:Gestational Age; D006339:Heart Rate; D006801:Humans; D011247:Pregnancy; D014159:Transducers; D014465:Ultrasonics / Q000295:instrumentation; D014463:Ultrasonography