"i have had nexplanon for 3 weeks today. i started bleeding after two weeks and 2 days. that was saturday and today is thursday. (5 days) i am still lightly bleeding. my periods are usually 3-4 days so i&#039;ll not sure how long this will last. the bleeding is very light. not really a problem for me because i expected this. i will check back in when it stops and let everyone know how long it lasted!"