Hi, I'm a regular user but need some advice on an ob/gyn matter so have re-registered myself. I'm 22 and have always had regular periods (since the age of 15, I've had it ever 28 days - you coudl set a clock by it) but recently (over the past 7-8 months) have been getting my period every other month only, and only roughly every 56 days at that - the gaps have been more like 50, 64, that kind of thing. There's probably less bleeding every other month than I used to get every month. What could cause this? Could it be something serious which might affect my fertility? What are the 'trivial' causes it could have? Thanks.