
Hi Maggiemay
As per the others - no need to stop HRT while waiting for your hysteroscopy. It may be (unless it's changed) that the official medical advice is to do so but that docs seemingly can decide whether or not to adhere to this.
For example over 10 years ago I was advised this when I had abnormal bleeding - to stop HRT prior to hysteroscopy but I got a second opinion and was able to remain on it.
More recently a couple of years ago or maybe less, after similar spotting, my lovely gynae GP said something along the lines of "What I should tell you is to stop HRT and see if the bleeding stops, but I'm not going to do that"!
Re your bleeding - on the whole, it is much more likely to be worrying to have an abnormal bleed post-menopause in the absence of HRT than if you are taking it when, as joziel says it is most likely the balance between oestrogen and progesterone that is causing your lining to thicken. I understand it is always a bit of a worry though.
As a matter of interest how long had you been period free before you started HRT. Had you been 12 months without a natural period (and not taking mini pill or anything)?
Hope it all goes well and try to stop worrying in the meantime.
Hurdity x