I have chosen the Mirena IUD - twice. I used birth control pills and the hormones messed my body up really bad. I was determined not to use hormones; but my OB told me that Mirena's hormones are trace amounts and they stay localized within the uterus (I think
this is right), so they don't enter the bloodstream. She also said the Mirena is safe to use while breastfeeding. I got my first Mirena 6 weeks after the birth of my now-3-year old. I had 6 weeks of spotting, then regular periods starting at about 6 months postpartum (I was still breastfeeding), and then by 8 months postpartum my periods stopped except for a day of very light bleeding. (The Mirena stops many women's monthly bleeding because it causes the lining of the uterus to become very thin, which is part of the way it works to prevent implantation.)
Well, a few months later, I decided I wanted another baby!
s So I had the Mirena removed in late November, and was pregnant by February.
Now I have my second Mirena in place, again inserted 6 weeks postpartum (it is most comfortable then since the cervix is still a bit open so the insertion is easier). I had more weeks of bleeding with the Mirena this time; have no idea why that is. But it stopped and I've had 2 regular periods now, as of 10 months postpartum.