Aha! That's probably what it was then XD I could hear like a... Whoosh, thud, whoosh, thud, whoosh, thud... Like there were two heartbeats. Whereas before I was just hearing the whoosh lol. I guess I must have been right above baby's heart and the thud was the actual heart beating and the whoosh must be the blood pumping?
No idea, but it was amazing haha. Shame baby kept wriggling away, couldn't get a really decent listen. Although he did deafen me at one point when he kicked the Doppler lol. The feedback was unreal... Must have been some hard kick!
XxX