I've been on nexplanon for 3 years had pretty accurate periods very heavy most of the time I'd go threw three to four heavy tampons or pads a day and would last two or three weeks but my last period was on time but very light in flow and color it was light pink and I only knew I was bleeding when I wiped it would come and go it wasn't constant at all and lasted five days the second day I was having a lot of back pain but it when away that night I'm not sure if I should wait til my next cycle or test but it never got heavy and it stayed light pink and I had no blood clots