What Causes Yellow Vaginal Discharge After Inserting Mirena IUD?

Hello. I had the Mirena IUD inserted approximately 3.5 months ago. Immediately the next day I noticed a yellow/brown discharge that smelled a little fishy and a little like blood. I assumed it was my body s reaction to a foreign object. I still have this odor. It comes and goes but is worse after my period ends. I have not changed sexual partners and was tested for STD s prior to insertion. There are no other symptoms. No itching, burning, discolored discharge (other than brown), etc. I ve began using an intimate wash for regulating the vaginal ph. I have not noticed a difference. I ve taken multiple at home infection detection tests that all were normal. Is this just a side effect of the Mirena? It started the day after insertion.