I feel sure it's due to hormones. I never knew what restless legs was, only had seen pharmaceutical ads for it, until I started hrt. I have had two spells of it, once on my first run of the progesterone phase of my hrt, and again on progesterone a few days ago. For several months in between the progesterone didn't do that to me, so I don't know why it happened again, but I don't think it's coincidence. It has to be due to the hormonal changes. This time I found that if I held my legs tense, I could stop the feeling and was able to get to sleep. It is a horrible thing to deal with.