Hi,

I dont know what it is, thats just what ive been told over the years, that its to do with pressure on the major arteries in your body and left side or sitting up is the way to sleep, but like i said that is mainly apparent for women in the 3rd trimester.

Considering you are still early on i would say go ahead and lay whatever way you want to until you get heavier.

It does get confusing how they always change their "theories" every couple of years with so many pregnancy and baby related things.

Do what you you feel most comfortable doing, you know you best