I have been a runner for about 15 years, usually running about 4-6 miles a day, 4-5 days a week. A few months ago I was feeling bored with this same old routine, so decided to see if I could run longer. And I could. So for about the past two months, I've increased my mileage to about 7-10 miles a day, though I only do this about 3-4 days a week; the other days I lift weights or something different.
Anyway, I've noticed that my cycle has gotten weird. It used to be around 30-32 days, but last month it was 32 days, and this month I think it's going to be MUCH shorter, like around 25 or 26 days (I have those "your period is going to come at any minute" cramps currently). I'm wondering if the increase in my running mileage could have something to do with this. Does anyone out there exercise a lot and had a weird change in the length of your menstrual cycle as a result?
And, for the record, though I don't think this should make much of a difference: I have a paragard (i.e. copper, non-hormonal) IUD, which is about 2.5 years old now. It hasn't interfered with the length of my cycles before, though I guess anything is possible...
Thanks in advance for your help!