Fluid intake symptoms and conditions

I am 27 had my Mirena inserted May 05 as I could no longer take the pill and I was diagnosed with endometriosis. It's known as a preventative for the spreading of endometriosis due to the lack of menstrual bleeding. I've not had menstrual bleeding since August 05 and not suffered from any side effects. I thought it was the best contraceptive ever invented, so happy with it.To think no periods, cramps, remembering to take the pill and not to forget how much money I've saved over the past years by not having to buy contraception or female toiletries. How ever I've had four UTI's since the Mirena was inserted. I never suffered from UTI's before the mirena was inserted. I have not changed my hygiene practises, fluid intake and I'm having less intercourse. So is it caused by the mirena??? I can't be sure but I'm am very suspicious. Think I'll consult my Gynecologist