What Is the Baby’s Heartbeat in the Mother’s Womb?
The sound of a baby’s heartbeat is one of the most emotional and reassuring experiences for every expectant parent.
It signals that new life is growing strong within the mother’s womb.
In the early weeks, the heartbeat can be detected only through ultrasound, and doctors monitor its rate to ensure the baby’s growth and well-being.
This blog explains when the heartbeat starts, what a normal fetal heart rate (FHR) is, how it changes during pregnancy, and why it’s such an important indicator of a healthy baby.
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🫀 When Does a Baby’s Heart Start Beating?
A baby’s tiny heart begins forming as early as 3 weeks after conception, though it’s too small to detect at that point.
By 5 to 6 weeks of pregnancy, the fetal heart starts beating — even before most mothers know they’re pregnant.
At this stage, the heart looks like a small tube that rhythmically contracts and expands.
The first heartbeat can usually be seen on an ultrasound scan (especially a transvaginal scan) as a flickering movement inside the gestational sac.
🩺 What Is the Normal Fetal Heart Rate (FHR)?
In the early stages, a baby’s heart beats much faster than an adult’s.
Here’s how the average fetal heart rate progresses during pregnancy:
Pregnancy Week | Expected Heart Rate (bpm) | Remarks |
5–6 weeks | 100–120 bpm | Heartbeat just begins |
7–9 weeks | 130–170 bpm | Fastest phase |
10–14 weeks | 150–180 bpm | Strong and rhythmic |
15–20 weeks | 140–160 bpm | Gradually stabilizing |
30+ weeks | 120–150 bpm | Slightly slower as baby grows |
BPM = Beats Per Minute
👉 A normal range is between 120 and 180 bpm in early pregnancy.
As the baby grows, the rate gradually slows to around 130–140 bpm by the third trimester.
This slowing down is perfectly normal — it shows that the baby’s heart is growing stronger and more mature.
🎧 How the Baby’s Heartbeat Is Detected
There are different ways to monitor the fetal heartbeat depending on the stage of pregnancy:
- Ultrasound (Sonography)
- Used from 5–6 weeks onward.
- The fetal medicine specialist checks the flickering movement inside the womb.
- Sound waves show the heartbeat as both a visual flicker and audible rhythm.
- Doppler Device
- From around 10–12 weeks, doctors can use a handheld Doppler to listen to the baby’s heartbeat.
- It converts motion into sound waves so parents can hear the rhythm.
- Regular Scans
- Every trimester scan includes heartbeat monitoring.
- Later in pregnancy, doctors may also do Non-Stress Tests (NSTs) to monitor the baby’s heartbeat during movement.
💓 What If the Baby’s Heartbeat Is Not Seen Yet?
If the first scan (done around 5 weeks) doesn’t show a heartbeat, there’s usually no need to panic.
It could simply mean that it’s too early.Doctors often recommend a repeat scan after 7 days to check again.
By 6.5–7 weeks, most viable pregnancies show a clear heartbeat.However, if the heartbeat remains absent even after 7 weeks, your doctor may discuss possible outcomes — such as delayed ovulation or, rarely, a non-viable pregnancy.
At Nisarga Diagnostics, our Fetal Medicine Foundation (FMF)–certified specialists ensure every detail is checked with compassion and accuracy.
⚖️ Why the Baby’s Heart Rate Matters
The fetal heartbeat reflects the baby’s oxygen supply and overall well-being.
An unusually high or low rate can sometimes signal issues like:
- Low oxygen levels
- Maternal stress or fever
- Umbilical cord compression
- Placental insufficiency
That’s why periodic ultrasound scans are crucial — to ensure consistent heartbeat patterns.
🩷 Heartbeat Changes During Pregnancy
- Early stage (6–9 weeks): Rapid increase — heartbeat develops strength.
- Mid pregnancy (12–20 weeks): More stable rhythm, correlating with baby’s activity.
- Late pregnancy (30+ weeks): Slower and stronger — heart now fully formed.
These variations are natural and help your doctor understand how your baby’s cardiovascular system is developing.
🧘♀️ How the Mother Affects the Baby’s Heart Rate
A mother’s lifestyle and emotions directly influence the baby’s heartbeat.
Here are key factors:
- Stress & Anxiety: May increase baby’s heart rate temporarily.
- Nutrition: Balanced diet ensures healthy oxygen supply.
- Hydration: Prevents fluctuations in fetal heartbeat.
- Sleep & Exercise: Regular gentle movement improves blood flow.
Simple relaxation, breathing exercises, and regular antenatal visits help maintain normal fetal health.
🩻 How Doctors Interpret the Heartbeat
Doctors use ultrasound to analyze several aspects of the heartbeat:
Parameter | Purpose |
FHR (Beats per Minute) | Detects baby’s cardiac activity |
Rhythm & Regularity | Indicates normal cardiac conduction |
Waveform (Doppler) | Shows blood flow through heart chambers |
Variation with Movement | Assesses response to oxygen |
These findings help doctors ensure your baby is receiving enough oxygen and nutrients via the placenta.
💬 Doctor’s Advice
“Hearing your baby’s heartbeat for the first time is magical.
But beyond emotions, it’s a strong indicator of the baby’s health.
A normal, rhythmic heartbeat gives us confidence that your pregnancy is progressing safely.”
— Fetal Medicine Team, Nisarga Diagnostics, Bengaluru
📍 Contact Information
Nisarga Diagnostics, Sanjaynagar, Bengaluru
📞 +91 88677 57594 / +91 91025 97025
🕒 Open all days — even Sundays & festivals
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.