I had a couple of weeks of breakthrough bleeding (post menopause I think but had stayed on cyclical because it suited me much better than ongoing bleeds). Went to doctor, who was concerned but not surprised, she said utrogestan not as effective as some other progesterone options, but it always worked previously! Tried / failed to do smear test to get sample. Tried/failed to do ultrasound at hospital in that they managed to inspect one ovary and part of uterus, which was described as 'bulky' and transverse, and similar thickening of endometrium of about 8mm. Tried/failed to do hysteroscopy without general anaesthetic. Eventually had it under GA as day case procedure. Got a Mirena fitted at same time. Have had minor breakthrough bleeding for about 2 months. I didn't have any fibroids (used to, but presumably they have shrunk). I think you do need the pathology checked though, it came through very quickly, which was a relief, but it also got me in touch with a doctor who was willing to work with me on what best treatment / HRT changes should be considered now. I am 62, so she'd prefer I stopped HRT, but I am still symptomatic, so trying gradually reduction in oestrogen patches, along with continual progesterone from Mirena.