Does a 'galloping horse' heartbeat mean you're having a boy or girl?

Maddy had the answer: "Boy = train. Girl = horse."

The reason a boy's heartbeat sounds like a train but a girl's sounds like a horse is, apparently, because a baby boy's heart is beating at under 140 beats per minute, while a girl's heartbeat is beating faster, at over 140 beats per minute.

What does a ‘boy train heartbeat’ sound like?

Here's a YouTube recording where you can hear a baby boy’s heartbeat (16 weeks): does it sound like a train to you?

What does a ‘girl galloping horse heartbeat’ sound like?

And here's the sound of a baby girl’s heartbeat: does it sound like a galloping horse? It's certainly beating consistently over 140 beats a minute...

What does the expert say?

"There is no evidence that a heartbeat sounding like a train or horse indicates a girl or a boy," says our expert GP Dr Philippa Kaye.

"A baby's heart rate – much faster than an adult's – will be somewhere between 110 and 160 beats per minute," she adds, "but there's no evidence that a baby boy's heart rate is slower than a baby girl's."

Indeed a 2006 study of 447 pregnancies by researchers at Wright State University in Ohio, US and published in Fetal Diagnosis and Therapy found "no significant differences between male and female fetal heart rates during the 1st trimester".

So if there's no evidence, why do so many of us believe it?

Maybe because there's always a pretty good chance (50/50) that you'll be right. And because when you are proved right, you'll likely to tell everyone about it – like MadeForMums community member Natasha: "Ours definitely sounds like a galloping horse and, true to the old wives' tale, we're having a girl!"

Then, of course, it's actually quite tricky to decide whether the heartbeat you're hearing is train-y or horse-y. Community member Aisha says: "Mine can sound like both; they are very similar. I think it sounds more like a horse but then I picture a train and it sounds like a train too!"

How reliable are other gender prediction tests?

If you're not convinced by the galloping horse / train heartbeat theory when it comes to finding out your baby's sex but want to know about more possible gender predictors, you can read about 28 (count 'em!) more here – or listen to our special podcast on this very topic with Dr Philippa.

• Podcast: How reliable are gender prediction tests?

Dr Philippa Kaye works as a GP in both NHS and private practice. She attended Downing College, Cambridge, then took medical studies at Guy's, King's and St Thomas's medical schools in London, training in paediatrics, gynaecology, care of the elderly, acute medicine, psychiatry and general practice. Dr Philippa has also written a number of books, including ones on child health, diabetes in childhood and adolescence. She is a mum of 3.

Read more...

• 29 signs you're having a boy or a girl
• When's the best time to book a private gender scan?
• Why these parents chose to have a 'genderless' baby