On the darn E for 4 years and 3 months, and while mine is not a cyclic dose, I will have two times, 14 days apart when I turn into a real puppy's mother, first one lasts a few hours to a day, the one at 14 + 14 (28 days) can last about 72 hours with leg edema and real monster attitude. My family and friends say they can tell what I am going to be like just by looking at the calendar.
In regard to my opening comment, its day 27.75 of this one.