ARRT Ultrasound Practice Test 2026 - Free Ultrasound Certification Practice Questions and Study Guide

Slow fetal heart rate is called bradycardia. The fetus normally runs about 110–160 beats per minute, so a rate that falls into the 90s is categorized as bradycardia. Tachycardia would be a rate that's faster than normal, arrhythmia means an irregular rhythm, and normocardic means a normal rate. So a fetal heart rate below 90 bpm fits bradycardia—and sustained bradycardia can indicate fetal stress or other concerns that warrant further evaluation.