"i just had my second mirena inserted after 5 years. before starting with it, i was always battling low iron (once my ferritin level was 4). after using the mirena, my period became super-light, and now my ferritin level is over 80. the second time around, the insert was a lot more painful. the doc said that it tends to be more painful as you get older (i&#039;m 46). i really have not had any side effects that i&#039;ve noticed with the mirena. not sure if i&#039;ll need it again, since i&#039;ll be 51 in five years."