I just finished my 4th since starting Atkins and the first one was the same day that I started, so I'm not going to count that one, so 3...the first 1 was late by almost a week and the 2nd one started about 5 days early, but this last one started exactly 4 weeks after the last one, so I'm hoping it stays that way. I've always been lucky with TOM--every 4 weeks, lasts 3 days, no cramps, backache, etc. I've noticed that my TOMs are a bit heavier and I can have some cramping and achiness now, but it's a good tradeoff (pounds lost for a bit of discomfort 1 day a month ). My TOMs are so regular that when it didn't come on the morning it was due I went and bought a pregnancy test and sure enough, I was pregnant with my third son (now 6). How's that for accuracy???