As of february 28th, i have had my mirena (levonorgestrel) iud in for 5 years. so it's now 5 weeks "expired". is it still effective?

Mirena (levonorgestrel) expired??: Would I bet a possible pregnancy - no however there is at least one study showing it may last as long as 7 years. - BUT the licensing documents filed for its approval indicate that it will deliver 20 mcg of the hormone for 5 years - so there may still be hormone left after the 5 year anniversary see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2770406/ I would play it safe and use a backup