I am 51 and definitely in the throws of perimenopause. My periods have been about every 3 to 3 1/2 weeks for the past half year. I am on my second period since starting keto. I didn’t even know it was coming. Usually I spot a few days before and I get very tender breasts. This time, no spotting, no breast tenderness, and 28 days since my last one. I did have some cramps but not too bad. So, keto or my stage in life? Don’t know. I am already curious to see what happens next month.