Hi Agate,
Just read your thread on immune issues and the FAQ ( you are great help by the way)
I have PCOS and have been on metformin for the last 4 years now.. Had my first cycle of IVF which failed, tested today (OTD) with a BFN

I had 5d transfer and the blasts were of good quality but I had flu like symptoms, cold and cough, sore throat the day after ET.. I did wonder where it came from as I didn't have any symptoms before.. I initially nought it could have the ice cold water I had before my ET but now reading through your thread it might have been my NK reacting to the embryos..
I need to get an appointment with my clinic (Oxford) to book in for my next cycle but do you think I need to get them to test my NK cells or have all of the immune tests done just in case..
Do I need to see a separate immunologist as well?? I am so desperate to move along after my failed IVF but would like to check everything before attempting the FET ( have 4 frozen ones from the IVF cycle).. Please advise..