Hearing your baby's heartbeat for the first time is one of the most powerful moments in pregnancy. But when exactly does it start, and what do those early beats mean?
Week-by-Week Heartbeat Timeline
| Week | What Happens | How Detected |
|---|---|---|
| 5–6 | Primitive heart tube begins contracting | Transvaginal ultrasound only |
| 6–7 | Electrical activity detectable — 90–110 bpm | Transvaginal ultrasound |
| 8–9 | Rate rises to 170–180 bpm (peak) | Transabdominal or transvaginal |
| 10–12 | Heart fully formed with 4 chambers | Standard ultrasound |
| 12–16 | Doppler detects heartbeat through abdomen | Handheld Doppler |
| 18–22 | Heartbeat clearly audible at antenatal visits | Doppler or anatomy scan |
What Is a Normal Fetal Heart Rate?
At 6–7 weeks, the normal range is 90–110 bpm. By 9 weeks, it peaks at 170–180 bpm, then settles to 120–160 bpm for the rest of pregnancy. This rate is roughly twice that of an adult at rest.
Does Heart Rate Predict the Baby's Sex?
The popular belief that a heart rate below 140 bpm means boy and above 140 means girl is a myth. Multiple studies have found no consistent relationship between fetal heart rate and sex. The rate depends on gestational age, activity, and individual variation — not gender.
What 'No Heartbeat' at 6 Weeks Means
Not seeing a heartbeat at 6 weeks does not automatically confirm miscarriage — especially if your cycle is irregular. Conception may have happened later than expected. A repeat scan 7–10 days later is standard protocol before any conclusions are drawn.
Important
If you are told there is no heartbeat, request a follow-up scan before making any decisions. Dating errors account for a significant proportion of these findings.
Using a Home Doppler
Home Dopplers can detect the fetal heartbeat from about 12 weeks, but they require skill to use correctly. Before 12 weeks they rarely work. False reassurance from not finding the heartbeat (often because of technique, not a problem with the baby) can delay medical care.