Baby's heartbeat sounds like a train? What it means

The midwife put the probe on your bump, there was a lot of crackle, and then it came: a fast, steady sound that half the room said was a train and the other half said was horses. Now you're at home searching what a train heartbeat means.

Here's when the heartbeat starts, when you can see it and hear it on the NHS schedule, what the sound actually is, and the honest answer on the boy or girl business. Plus the one thing a heartbeat can't tell you, which matters more than any of it.

The NHS timeline, in short:

• Week 5: the tiny heart is forming and will beat for the first time around now.
• Week 6: sometimes the heartbeat can be picked up on a vaginal ultrasound scan, but you're unlikely to be offered one unless you've had IVF.
• Around 10 to 14 weeks: the dating scan, and the heartbeat can be picked up on an ultrasound scan.
• Week 16: a midwife appointment, and you might get to hear the heartbeat for the first time.
• 16 to 24 weeks: you should start to feel movements, often after 20 weeks with a first baby. From then on, movements are the check, not the heartbeat.

When does a baby's heartbeat start, and when can you see it?

Earlier than most people realise. The NHS week by week guide says the heart is starting to form at week 5 and will beat for the first time around then. That's about three weeks after conception, around the time many people are only just finding out.

Seeing it is a separate question, because it depends on being scanned. At 6 weeks the NHS says the heartbeat can sometimes be picked up on a vaginal ultrasound scan, but you're unlikely to be offered one unless you've had IVF.

For most people the first look is the dating scan, offered at around 10 to 14 weeks according to the NHS 12-week scan page, and by then the NHS says the heartbeat can be picked up on the scan.

On screen it's a flicker rather than a thump.

The sonographer will usually point it out, and if they don't, ask.

What week can I hear my baby's heartbeat?

Usually 16 weeks. The NHS week 16 page says you may see a midwife around now and might get to hear your baby's heartbeat for the first time. The "might" is honest. Your baby's position, where the probe sits, your build and how your dates fall all decide whether it's easy to find on the day.

The full list of appointments and what happens at each is on the NHS antenatal care and appointments page. Scans at around 12 and 20 weeks, midwife appointments from 16 weeks, and more of them towards the end.

Why does the baby's heartbeat sound like a train?

Because it's fast and it's coming through a speaker. A baby's heart beats much faster than yours, and the handheld listening device your midwife uses turns that into a quick, even chuff, chuff, chuff. Some ears hear a steam train. Some hear horses galloping. The forums have both camps and they will never agree.

It's the same heartbeat either way. What changes the rhythm you hear is where the probe is sitting and how your baby is lying, so the same baby can do a train at one appointment and horses at the next. If you want to hear it again between appointments, the answer is further down, and it isn't a home doppler.

Does a train heartbeat mean a boy?

No. The old wives' tale says a train means a boy and galloping horses means a girl, and there's a cousin of it that says a heart rate over 140 beats a minute means a girl and under 140 means a boy. Both are for fun. Neither has anything behind it, and the NHS doesn't offer either as a way of finding out.

The rate one falls apart quickly once you know that every baby's heart rate moves around. NICE's guideline on fetal monitoring in labour treats a stable baseline anywhere between 110 and 160 beats a minute as normal, for boys and girls alike, and it changes minute to minute. One reading at 16 weeks sorts nothing.

If you like a guess, our nub theory guide is the same sort of fun with a scan photo and a protractor. The NHS route is to ask at the 20-week scan, if your hospital's policy allows it, and the NHS says even then the sonographer can't be 100% certain.

What should my baby's heart rate be?

Faster than yours, and nobody will ask you to keep track of it.

The number your midwife or sonographer notes is theirs to interpret, and it's read alongside everything else about the pregnancy rather than on its own.

For what the range looks like, NICE's guideline for monitoring in labour treats a stable baseline between 110 and 160 beats a minute with normal variability as low risk. That's the labour figure, quoted as theirs. If your midwife says the heartbeat sounds fine, that's the reading that matters.

What a normal reading never does is tell you the sex, and what it can't do is stand in for the check that matters later, which is movements.

Can I use a home doppler to check the heartbeat?

You can buy one. The NHS says don't use it to check on your baby, and it's worth reading their exact words on the your baby's movements page: a home doppler is not a reliable way to check your baby's health, and even if you hear a heartbeat, it doesn't mean your baby is well.

That's the bit that catches people out. Hearing a heartbeat feels like reassurance, and it isn't, because a baby who isn't well can still have a heartbeat. So a doppler is not a substitute for calling your midwife about movements. Not a partial one, not a first step. Not at all.

If your baby is moving less than usual, you can't feel them moving, or the pattern has changed, the NHS says to call your midwife or maternity unit immediately, and not to wait until the next day, even if it's the middle of the night.

Don't check with a doppler first. Call.

Movements start between 16 and 24 weeks, the NHS says, and after 20 weeks if it's your first. Our piece on feeling your baby move covers what you can and can't feel in the early weeks.

Questions we get asked

What does a baby boy's heartbeat sound like?

Exactly like a baby girl's. Fast, even, and through the midwife's speaker somewhere between a train and a gallop, depending on where the probe is. The idea that boys sound like trains is a tale, and a fun one, but there's nothing in it.

Horse or train heartbeat, what's the difference?

Only in the ear of the listener. Both describe the same fast rhythm, and the same baby can sound like one on Tuesday and the other a month later. Neither says anything about the sex.

From which week does the baby's heart beat?

Around week 5 of pregnancy, the NHS says, counted from the first day of your last period. It can sometimes be seen on a vaginal scan at 6 weeks, is usually seen at the dating scan at 10 to 14 weeks, and is often first heard at the 16-week midwife appointment.

Is a heart rate over 140 a girl?

No. Every baby's rate moves around, and NICE treats anything between 110 and 160 as a normal baseline in labour, whatever the sex. It's a guessing game, and a coin does as well.

What if the midwife can't find the heartbeat at 16 weeks?

It happens. Your midwife will say what they want to do next, and that's the conversation to have in the room rather than at home with a search bar. If it's between appointments and you're worried about movements, that's a call to the maternity unit, not a doppler.

When the heartbeat's been found and the appointment's over, the pregnancy collection has the bits for the weeks in between.