M.B.
Have you read the warnings on this device? What ever doctors say about it, the final decision falls on the patient, hoping that you feel comfortable and responsible for your choice.
This is what I read.. maybe bleeding is mistaken for periods.. but really, if it messes with your natural cycle, it can't be all that great..
3. Vaginal bleeding
In the 2 largest clinical trials with ParaGard® (see ADVERSE REACTIONS, Table 2), menstrual changes were the most common medical reason for discontinuation of ParaGard®. Discontinuation rates for pain and bleeding combined are highest in the first year of use and diminish thereafter. The percentage of women who discontinued ParaGard® because of bleeding problems or pain during these studies ranged from 11.9% in the first year to 2.2 % in year 9. Women complaining of heavy vaginal bleeding should be evaluated and treated, and may need to discontinue ParaGard®. (See ADVERSE REACTIONS.)
source: http://www.drugs.com/pro/paragard.html