Fetal Heart Rate in Pregnancy: Normal Range & Variations
For most expecting parents, hearing the baby’s heartbeat for the first time during a pregnancy scan is an unforgettable and emotional moment.
That rhythmic sound instantly creates a deep connection and reassures parents that their baby is growing well.
However, as pregnancy progresses, many parents start noticing that the fetal heart rate (FHR) mentioned in scan reports keeps changing.
Sometimes it is lower, sometimes higher, and this variation often leads to anxiety:
“Why is my baby’s heart rate less today?”
“Last scan it was higher — is something wrong?”
“Doctor, should we worry?”
At Nisarga Diagnostics, we frequently receive these questions during pregnancy scans.
This blog explains fetal heart rate, its normal range, why it varies, and when medical attention is required — in simple, reassuring language.
Watch our video on : Fetal Heart Rate in Pregnancy
💓 What Is Fetal Heart Rate?
Fetal Heart Rate (FHR) refers to the number of times a baby’s heart beats per minute while inside the mother’s womb.
It can be detected as early as 6–7 weeks of pregnancy using ultrasound.
As pregnancy advances, fetal heart activity becomes clearer and easier to measure.
FHR is routinely assessed during:
Early pregnancy scans
NT scanAnomaly scan
Growth scans(7th, 8th, 9th month)
Over time, this can result in:
Restricted fetal growth
Low birth weight
Delayed organ development
✅ What Is the Normal Fetal Heart Rate Range?
The normal fetal heart rate range is between 120 and 180 beats per minute (bpm).
This range is considered healthy and reassuring during pregnancy scans.
| Fetal Heart Rate | Interpretation |
|---|---|
| 120–180 bpm | Normal |
| <120 bpm | Fetal Bradycardia |
| >180 bpm | Fetal Tachycardia |
⚠️ Important:
A single reading slightly above or below the range does NOT automatically mean a problem.
🔻 What Is Fetal Bradycardia?
Fetal Bradycardia means the fetal heart rate is less than 120 bpm.
Possible reasons:
Baby is sleeping or inactive
Temporary change in fetal activity
Early gestational age
Transient cord compression
Rarely, heart rhythm abnormalities
In most cases, mild bradycardia is temporary and resolves on its own.
🔺 What Is Fetal Tachycardia?
Fetal Tachycardia refers to a heart rate above 180 bpm.
Common reasons include:
Baby is very active
Maternal fever
Anxiety or stress during scan
Dehydration
Medications
Rare fetal rhythm disorders
Again, activity-related tachycardia is common and usually harmless.
👶 Why Does Fetal Heart Rate Keep Changing?
This is the most important point every parent should understand.
👉 Fetal heart rate is NOT constant.
It varies mainly due to baby’s activity level, just like in adults.
🏃 When the Baby Is Active
Baby moves, kicks, stretches
Heart rate increases
FHR may go closer to 160–180 bpm
😴 When the Baby Is Resting or Sleeping
Less movement
Lower heart rate
FHR may drop closer to 120–130 bpm
✅ Both situations are completely normal.
😊 Why Parents Are Happy During the First Scan — and Anxious Later
First Scan Experience
Hearing heartbeat for the first time = pure joy
Parents are emotionally reassured
Focus is only on “heartbeat present or not”
Later Scans (NT, Anomaly, Growth Scans)
Parents start comparing numbers
They remember previous scan values
Small variations create unnecessary fear
👉 This is where proper counselling plays a major role.
At Nisarga Diagnostics, we make it a point to:
Explain heart rate variations
Show fetal movements on screen
Reassure parents in real time
🩺 When Should You Really Worry?
Although variations are common, medical attention is needed if:
Heart rate remains persistently <120 bpm
Heart rate remains persistently >180 bpm
Associated with:
Reduced fetal movements
Abnormal scan findings
Maternal illness
Abnormal rhythm patterns are observed
In such cases, doctors may advise:
Repeat scans
Doppler studies
Fetal echocardiography
Obstetric consultation
🩷 Final Words
Hearing your baby’s heartbeat is one of the most beautiful moments of pregnancy.
Understanding that variation is normal helps reduce stress and anxiety.
If you ever have doubts about scan findings, early clarification and expert evaluation are always better than worry.
Nisarga Diagnostics is committed to providing accurate pregnancy scans, expert interpretation, and compassionate care for every expecting family.
Founder of Nisarga Diagnostics, is a renowned fetal ultrasound specialist with over 20 years of expertise. An alumnus of Government Medical Colleges in Mysore and Bangalore, he also holds a D.N.B. from the National Board of Examinations, Delhi, and certification from the Fetal Medicine Foundation, London. A former Professor and HOD, he has trained countless PG students and junior radiologists, shaping the future of fetal imaging in India.