According to a study published in the British Journal of Obstetrics and Gynaecologists, mums-to-be who sleep on their backs during the third trimester are more than twice as likely to suffer a stillbirth than those who nod off on their side.
And the exact reason why is inconclusive, previous research suggests that when a woman lies flat, the combined weight of the baby and womb puts pressure on the blood vessels, which then restricts blood and oxygen flowing freely.
So, what about those of us who wake up on our backs?
According to the study’s lead researcher Professor Alexander Heazell, it’s the position you start in that matters most.
“What I don’t want is for women to wake up flat on their back and think ‘oh my goodness, I’ve done something awful to my baby,” he said.
“The question that we asked was very specifically what position people went to sleep in and that’s important as you spend longer in that position than you do in any other.”
“And also, you can’t do anything about the position that you wake up in but you can do something about the position you go to sleep in.”
If you're struggling to catch the zzz's on your side, try placing some pillows behind you to prevent you rolling backwards. It's not a guaranteed way to stop you lying on your back, but it might help make it a little more comfortable.