At nearly 18 weeks, I've been making a real effort for several weeks to start sleeping on my side, but without fail I end up flat on my back. How much of a problem is this? I've only put on 2 pounds so far, so don't believe my bump weighs much yet to be pressing on blood vessels etc. Surely in years gone by, before all the medical advice, ladies were sleeping on their backs all the time. I've read about these special long pillows to keep you on your side, but to be honest, there's no room for it in a standard double bed! Anyone else having this problem? And are there any ladies who've slept on their backs all the way through?