You're fine. In third trimester lying flat on your back puts pressure on an artery but you'll find yourself avoiding doing that intuitively as it feels uncomfortable. Until then don't worry, and there's not much difference between being on your left/right. Officially being on your left means the least pressure on your artery but there's not enough of a difference to worry about it. Whatever you need to get comfy!
It really doesn't matter until your over 20 weeks. Being on your back after this time could put pressure on the inferior vena cava which is a vein that carries deoxygenated blood back to heart. Try a long pillow down the right side of your back
I'd sleep however you are comfortable. You will move during the night anyway. I tried to sleep on my left side, but I got uncomfortable after a while and turned over. I sleep on my back mostly and I did that even at the end of my pregnancy.
Thingyma, sorry but whether that is true or not (I believe it is), can you point to the research that shows the damaged or dead babies from their mums sleeping on their backs? This sort of scaremongering makes pregnancy miserable for unconfident and anxious people.
OP YOU will feel uncomfortable when something isn't working well. If you are happy on your back for a couple of hours at 30 weeks etc. then do that. I used to occasionally as it was comfortable but then would wake uncomfortable and plop over.
I'm almost 23 weeks pregnant and always wake up on my back (mainly because DH is poking me because I'm snoring!). There is advice that says left side sleeping increases blood flow to your pelvis but if you're uncomfortable and not sleeping then sleep how ever you need to.
@YoureNotASausage It's not scaremongering, women from approximately 20 weeks are advised to lie in the left lateral position because of the risk of inferior vena cava syndrome. I really do not appreciate your tone. I am a HCP and was giving advice based on medical fact that was related to the question that the OP asked.
Glad you backed it up a little. There is no reference to damage to baby (in the wiki note, can't access the other reference) and for the mother just pain, reduced blood pressure, muscle twitching and fluid retention. All of which probably happen when heavily pregnant and sitting in a chair the wrong way and we end up repositioning ourselves because it gets uncomfortable or we feel dizzy. Just like we do at night when we wake up while heavily pregnant. Your post indicated clearly that the OP should only sleep on her left side from 20 weeks and as she asked about damage, you indicated that yes she could cause damage with your post. I think that's irresponsible as you could have left the OP terrified to sleep comfortably for 20 weeks.
So my point was that yes, baby can put pressure on blood supply when sleeping on your back and right side but if it's comfortable it's likely not interfering with your blood supply (you'll know about it when it does) and as far as I've ever heard (contradict me if you have evidence), there's no indication of harm to your baby.
It's important that people understand what's behind guidelines rather than just being told don't do this and spending time scared and uncomfortable.
That's interesting Six. I must admit that I never felt right about sleeping on my back once I got to the last few weeks, hugely uncomfortable and just feels yuck. I think I personally wouldn't sleep on my back and would maybe make a little effort (not the the detriment of my sleep) to lie on my left as much as possible for the last 4 weeks or so. It's important to understand the reasons behind these things and judge the risk fairly. Nothing should lead to massive anxiety and I've seen so many people on here in a blind panic because they are a deli sandwich or had a bath without knowing they were pregnant or slept on their back) I think our bodies are pretty smart and instinct goes a long way in pregnancy.
I read that you're meant to sleep on your left hand side and asked my midwife at my last appt. She said, sleep in whichever position you feel the most comfortable. I'm curr 21 weeks and sometimes feel sleeping on my back the most comfy. A couple of weeks ago I was sleeping on my left but not comfy, I switched to my right and definately felt my baby 'turn' - I felt her head pressing inside me as she moved around... at my 20 week scan last week, they confirmed she's now with her head facing my left side (where at a 17 wk scan her head faced my right side). With her this way around, I feel most comfortable sleeping on my right hand side - so I decided to follow my midwife's advice and just go with what feels the most comfortable. (She also said that sleeping on your back could cut off/reduce circulation but that you would feel very uncomfortable... sounds silly but I was told my womb is 'anteverted' and so I think this may be why I still feel comfortable sleeping on my back sometimes)