Birth Control Pills & Spotting

I have been on Amethia for a little over a year and only have a period once every three months. I have recently been spotting brown blood. This past month it's happened twice. The first time it was about five days, stopped for a couple of days and then I started spotting again. This time it's lasted about two weeks. Do any of you know what could be causing this? Also, I will be coming off of the pill in 20 days because my husband and I are trying for baby #2 starting in August, so is this even really a concern? Thanks!