Hi Kristen, I started ferning a second time (small ferns mixed with pebbles) five days before AF arrived. I got very excited as I had the idea that you can get ferning as a result of increased oestrogen levels when pregnant, but no such luck. The other thing that occured to me is that the ferning results from a higher salt content in your saliva so possibly I had been on a salty food jag (being premenstrual my diet gets very very baaaaaad).
:-)