"i have had the implanon since june 2015 and i have to say it i hadno pregnancy but the only down sides about it was that no one told me i would have bruising for 10 days on my left arm and that it would hurt so much during that time. my periods have always been regular, each month 3-5 days. but the other down side is the gaining weight. i always weight around 140 and i went up to almost 180. never had happened and i have been trying to lose weight but nothing seems to work. it&#039;s a great birth control but the weight is no good."