OMG I have being getting this for years. I have being to dr's about it one telling me I needed an MRI. The MRI was all clear and now I hear it can be something as simple as wax build up? It is so anoying and I can't sleep for the thud and then the worry something isn't right. Off to get my ears cleaned asap see if that stops. Then the BP. It was also so much worse when pregnant. It makes sense that it would be worse in pregnancy with the extra blood you are carrying around and increased pressure.