"implanon is very effective! this will be my 3rd year having it. worst part is the irregular bleeding, sometimes i&#039;ll go 3 months no period &amp; then the next 2 months i bleed a bit every other week.. and i would say my normal pms is a bit worse &amp; my breast are awfully sore but its bound to have some side effects. none of them are long-term issues but very unpredictable."