I'm 4 months pregnant, and they advise that you start sleeping on your side at that time, to ensure optimal blood flow to the uterus (apparently, lying on the back can restrict flow). Well, I tried this and it is HORRIBLE! If I sleep on my left side, I wake up in the middle of the night with my left leg asleep! If I turn over to my right side, the same thing happens to that leg!!! I've tried putting a pillow between my legs, under my waist to support my belly, even going commando (to make sure it wasn't my undies too tight!! lol) but nothing is helping!! Can this lack of blood flow to my legs hurt my baby? I'm not overweight at all, I've gained about 6 lbs so far.... should I call my doctor??