Levonorgestrel
"Today marks 6 months with my Liletta IUD...which I love. Insertion was painful, as expected, but nothing I couldn't handle. Cramping and spotting lasted a few days after...and for the first 4 months I spotted lightly for 8-10 days, always 28 days apart...so I tracked those times as my period. Very minimal cramping aside from  the early cramps due to insertion.  Didn't take long for the strings to soften and curl up so my partner could not feel them during intercourse. My side effects do include weight gain and a struggle to lose it despite consistent exercise and healthy eating, and dry skin, and bloating/constipation."