Hello ladies! This is my own personal story about my mirena iud side effects, specifically gaining weight and being completely unable to lose it. After deciding to remove my mirena IUD I did end up losing weight and alleviating the side effects of water weight gain, water retention, and gas bloat. I also discuss my mirena removal. I hope you like my story and leave comments. below. mirena weight gain weightloss, mirena side effects, mirena iud, mirena removal, mirena iud side effects.