"i have had nexplanon for about 4 months and overall i love it! i definitely do have some side effects although. these include: very light irregular bleeding, my periods last about 3 days. a noticeable decrease in immune system strength, since the implant i&#039;ve gotten a cold every month verses having a cold once or twice a year. headaches, i used to have intense headaches with my previous birth control and i still have them with this kind but not as severe. as for positive aspects of this birth control, i never have to worry about it or worry about taking a pill everyday, being late with a shot or risk an iud falling out. my periods are so minimal i almost forget i have them, i haven&#039;t gained weight or had any serious side effects!"