When I was pregnant with DS1, towards the end I occasionally heard this odd click noise - once it was so loud that SIL heard it too.
I'm now 33 weeks pregnant with DC2 and I've recently been hearing (if that's the right word for it, as it's more a feeling at the back of my neck - I know it sounds totally mental) the odd kind of fizzy bubbly sound, and I've just heard the first faint click like DS did.
Has anyone else ever had this? I asked the midwife last time and she'd never heard of it. DS is fine and normal and hasn't "clicked" since being born - but what are they doing in there to make such an odd noise?