It is generally recommended to stop lying on your back during pregnancy after about 20 weeks (mid-second trimester). At this point, the growing uterus can put pressure on major blood vessels like the inferior vena cava, which may reduce blood flow to your heart and the fetus. This can cause symptoms such as dizziness, nausea, and low blood pressure, and may affect fetal growth and increase risks like stillbirth. Instead, side sleeping, particularly on the left side, is considered safer for both you and your baby during the second and third trimesters of pregnancy.
Some research suggests it might be safe to sleep on the back up to about 28-30 weeks, but the safest guidance is to avoid back sleeping after 20 weeks whenever possible to promote better circulation and reduce risks.
If you wake up on your back occasionally, it is usually not a cause for alarm, but you should try to start sleep lying on your side. Listen to your body and stop lying on your back when it starts to feel uncomfortable or causes symptoms like dizziness or difficulty breathing.
In summary, to protect your health and your baby’s, stop lying on your back after around 20 weeks of pregnancy and prefer side sleeping for the remainder of your pregnancy.
