> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sonohealth.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Fetal Doppler Accuracy & Limitations — What It Can and Cannot Do
> A home fetal doppler can detect your baby's heartbeat for reassurance and bonding. It cannot diagnose fetal distress, confirm fetal wellbeing, or replace prenatal care. Full accuracy and limitations explained.
**A home fetal doppler can detect and let you hear your baby's heartbeat for reassurance and bonding — but it cannot diagnose fetal distress, confirm your baby is well, or replace prenatal care.** Understanding what it can and cannot do is essential for using it safely and responsibly. For a week-by-week detection guide, see [when can you hear the heartbeat](/fetal-doppler/questions/when-can-you-hear-heartbeat).
## At a Glance
| The HeartBeats™ CAN | The HeartBeats™ CANNOT |
| -------------------------------------------- | ---------------------------------------- |
| Detect fetal heartbeat (from \~12 weeks) | Diagnose fetal distress |
| Display heart rate in BPM | Confirm fetal wellbeing |
| Provide bonding moments between appointments | Replace prenatal ultrasounds |
| Work from home without a clinic visit | Monitor high-risk pregnancies |
| Detect that a heartbeat is present | Detect heart rate abnormalities reliably |
## What the Device Does Well
**Heartbeat detection for bonding:** The HeartBeats™ reliably detects fetal heart tones in most pregnancies from around 12–14 weeks of gestation using a 2.5 MHz probe. From 16 weeks onward, detection is consistent for most users.
**Heart rate display:** The digital BPM display provides a real-time readout of the detected rate, allowing parents to distinguish the fetal heartbeat (110–160 BPM) from their own pulse (60–100 BPM). See the full [normal fetal heart rate ranges](/fetal-doppler/heartbeat-normal-ranges).
**Peace of mind:** Many expectant parents find regular listening sessions reduce anxiety between prenatal appointments. This is the primary value of a home doppler.
## Key Limitations
### 1. Cannot Confirm Fetal Wellbeing
A detectable heartbeat does not mean the baby is healthy or not in distress. Fetal monitoring in clinical settings uses continuous CTG (cardiotocography) that tracks heart rate patterns over time — not just the presence of a heartbeat. A single BPM reading from a home doppler cannot replicate this.
### 2. Cannot Detect Heart Rate Abnormalities
Clinically significant fetal heart rate patterns — such as decelerations, prolonged bradycardia, or reduced variability — require sustained monitoring and clinical interpretation. A home doppler shows a single instantaneous BPM, not the patterns that matter for fetal assessment.
### 3. Cannot Replace Kick Counts
If you notice reduced fetal movement, **do not reach for your doppler first** — contact your healthcare provider. A detectable heartbeat does not rule out fetal compromise in the context of reduced movement. See [reduced movement: why a doppler is not the answer](/fetal-doppler/reduced-movement-what-to-do).
### 4. User Skill Affects Results
Finding the heartbeat requires technique, patience, and the right gestational age. A failed session — especially before 14 weeks — usually reflects positioning, not a problem with the pregnancy. Misidentifying sounds (maternal pulse or placenta as fetal heart tones) is a real risk without proper guidance.
### 5. Not a Substitute for Professional Monitoring
The HeartBeats™ is not designed for, and should not be used as, a substitute for:
* Non-Stress Tests (NST)
* Biophysical profiles
* Clinical Doppler monitoring
* Routine prenatal ultrasounds
## Accuracy at Different Gestational Ages
| Week | Likelihood of Detection | Notes |
| ----------- | ----------------------- | ------------------------------ |
| 8–10 weeks | Low | Uterus still behind pubic bone |
| 10–12 weeks | Variable | Possible but not reliable |
| 12–14 weeks | Moderate–Good | Most users find with patience |
| 14–16 weeks | Good | Reliable for most users |
| 16+ weeks | High | Consistently detectable |
## The Safe Use Standard
If you have any concern about your baby — reduced movement, pain, bleeding, or inability to find the heartbeat after 16 weeks — contact your healthcare provider immediately. Do not use your doppler as a substitute for medical evaluation.
The HeartBeats™ is best described as: **a bonding tool that uses the same technology as clinical dopplers, in a home-use form factor, for reassurance between appointments — not for clinical assessment.**
FDA-Cleared · Best for Reassurance & Bonding · \$69
**Related:** [Overview](/fetal-doppler/overview) · [Safety](/fetal-doppler/safety) · [Normal Heart Rate Ranges](/fetal-doppler/heartbeat-normal-ranges) · [Is a Fetal Doppler Worth It?](/fetal-doppler/is-a-fetal-doppler-worth-it)