Almacfarlane
Unfortunately your post got missed - holiday season and all that!
Any bleeding is likely when you first start continuous combined HRT or the Mirena coil and your bleeding is most likely due to the increased oestrogen. Depending on your age and period pattern, it can sometimes happen that ovarian function spontaneously resumes even after POF - so I understand, although I'm not sure how often this is known to occur? You should be able to phone up and get the results of your bloods and you can ask them at the same time what the next stage of any investigation will be.
How old are you and how long without periods before starting the HRT? Ah - if you've had the Mirena coil in for some time (before you started the patches) then you won't know where you are in menopause re your cycle? I presume then thast POF was diagnosed on the basis of two blood tests but I am interested to know what symptoms prompted you to have tests - if you have had the Mirena coil in for contraception anyway.
Hurdity x