All the posts I've read talk about irregular periods being either the length of the period itself or the heaviness of it.

The days of my cycle were always consistent (27-28 days) until about 5 yrs. ago. Since that time, I've experienced bouts of "no period" (although this has only happened twice) and then "up and down" cycles. What I mean by this is that one month, my cycle will be 23 days, then the next it might be 37 days and then back down to 25 days the next month and so on.

I'm wondering if this variation is a result of perimenopause? I'm 37 and when undergoing fertility treatments a few years ago (with no luck I might add), the word "perimenopause" was mentioned.