When you have an early pregnancy scan, one of the things the sonographer will assess is your baby's heart rate. But why is this measurement so important?
Why Heart Rate Matters
The embryonic heart rate provides additional important information on the health and future success of the pregnancy. It's one of the key indicators that your pregnancy is progressing normally.
Normal Heart Rate Ranges
Heart rate expectations vary by gestational age:
| Gestational Age | Normal Heart Rate |
|---|---|
| Up to 6.2 weeks | 100 beats per minute |
| 6.3 - 7.0 weeks | 120 beats per minute |
| 8+ weeks | 140-170 beats per minute |
The heart rate typically increases through the first trimester before settling into a more consistent range.
How Is It Measured?
During early pregnancy, technicians use motion mode (M-mode) rather than Doppler to measure the heart rate. This method is preferred because:
- It avoids potential tissue damage to the early embryo
- Doppler uses more energy and is not recommended in the first trimester
- M-mode provides accurate measurements safely
What You'll See and Hear
During an early scan:
- You'll see a visible heart flutter on the screen
- Audio may not be available (Doppler audio is often avoided early on)
- The sonographer will count and record the rate
What Does a Slow Heart Rate Mean?
A slower-than-expected heart rate during the first trimester may indicate a poor pregnancy outcome. If this is detected:
- A follow-up scan will be scheduled within 10-14 days
- This allows time to reassess and confirm viability
- Many pregnancies with initially slow rates do continue successfully
The Reassurance of a Strong Heartbeat
Seeing a good, strong heartbeat is incredibly reassuring. It significantly reduces the risk of miscarriage and indicates healthy early development.
Book your early pregnancy scan at Ultrasound Ireland to see your baby's heartbeat. Call 01 210 0232.