I must tell you that for the two years I had my mirena in, it was very nice to not deal with a period! Although, I had mine inserted directly following the birth of my son, and I never lost any baby weight, and in fact, I gained more. I had it taken out after two years of being in, and I switched to the ortha evra ring. I lost a little weight. It was not until after being so frustrated with myself, that I decided to just use the old fashioned "condom" and call it quits with everything else that any more pounds started to shed off. I am only telling you this because it was my experience. Every body works differently. If you are close with your doctor, I would trust what they tell you foremost.