A.S.
I initially thought Paraguard as well....and although it has no hormones, it is thought to cause more/heavier bleeding during periods. Plus it is made of copper, and I have had reactions to copper jewelry in the past, so I went with Mirena. I was concerned about the hormones as well, as I am nursing and my body tends to be very sensitive to hormones (PMDD symptoms during the week before my period). But, the hormones in the Mirena are a very small amount and very localized (ie it doesn't run through your blood stream like BCP do). I have had it for 7 months now and it has been wonderful. It was a little painful getting placed, but nothing someone who has been through birth can't handle. My period has come back since I've been on it, but it's so incredibly light that if I'm not paying attention I don't even notice it (extremely light discharge for 1 maybe two days, but I also break out and get a little bloated etc like I always used to do during my period). It hasn't interfered with nursing one bit and my 18 month old is still going strong. I would highly recommend it. I have a girlfriend on Paraguard as well and she has been happy with it as well (although we have not discussed her monthly symptoms in detail LOL).
Good luck!