I'm a 29 years old and I have a 18 month old son. Well after I had my son, I went on birth control pills and had a very normal period as I always had, starts out brown and then red and from light to medium to light flow and lasted from 7-9 days, I have always been like that well 10 months ago I got off the pill and I was still the same and about 5-6 months ago my periods have been really changed, they are black to little little bit of red back to black and really short to 3 days. I've talked to my dr. and she said its probably my thyroid well the test came back negative because I never heard from her and I haven't seen her since. What could be causing this and will it make a difference when we try to get pg again.