Mirena spotting

Me

Hello! I’ve had mirena for 6 months now.. first couple months I had 14 days of bleeding (starting on my regular cycle time) ... the next was shorter then the next was one day of bleeding and now this month i spotted about 4 days and started on the day my period was supossed to start but it was only brown blood... not pink or red... normal? I’m thinking it’s normal... but wanted to know what others thought

Thanks!