I researched it on the internet when I was pregnant with either Bean or Fish. There is no one cure: from all the differing sources I read I found that what helps one person doesn't do anything for someone else. In fact, it seems that sometimes the thing that makes it a lot worse for one person is what cures it for another.
When I was pregnant with Fish, my friend clued me in to a natural remedy for those horrible painful leg cramps I also sometimes get when I am pregnant. I started taking it and discovered that not only did the leg cramps completely stop but the restless leg syndrome disappeared as well.
It's called A to B Calm and it's basically calcium and magnesium in a format that is assimilated by your body very quickly. You mix the powder with boiling water. Once it's dissolved I cool it down with ice cubes and add a little juice. I make it up at bedtime and if I forget and go to bed without it and can't sleep because of the RLS, I go make myself a cup and I'm asleep in minutes.
I bought this jar when I was pregnant with Fish and it's only now almost gone. Yeah, it lasted me awhile.
Calcium/magnesium really seems to be the ticket for me with RLS. I have discovered in more recent years that if I am diligent in taking a good cal/mag supplement daily I don't get the RLS and I don't need to make a cup of Calm at bedtime. But I often forget, or run out, or whatever, and my jar of Calm is always there to help me out.
There are so many discomforts of pregnancy and so many times it is hard to find a solution that even eases the discomfort, let alone takes it away entirely. I am so grateful that this malady is so easily cured in my case.