Hi Ladies- I thought you would be interested in this article from the high impact journal- Human Reproductive Health. It is called The effect of a levonorgestrel-releasing intrauterine system on uterine artery blood flow, hormone concentrations and ovarian cyst formation in fertile women. You can google the article to get the abstract but in summary they have shown that there is a significant reduction in systemic progesterone for women using the IUD in the second half of the cycle (but oestrogen still increased to normal levels. Many of you have already speculated that your symptoms may be due to low progesterone (leading to relative oestrogen dominace). This made me feel a bit better- knowing there is true scientific proof that the Mirena messes with your systemic hormones! A good article to point your GP to as well.