"i have had nexplanon for 4 or 5 months now. the first week i was very moody. but my body adjusted quickly. my periods lasted two weeks for the first two months. i would spot the first week than have a heavy flow the next. i didn&#039;t have a period the third month. and this month it was a normal week long period. that doesn&#039;t bother me much though. the only downfall for me is that i have put on quite a bit of weight since i got this birth control. i am now bigger than i was while pregnant. and my breasts have gone up from a large b/small c to a large c. other than the weight gain i have no problems with the nexplanon implant."