Written by Monique Maitland (Registered Midwife/Nurse & Founder of The Middee Society)
Achieving a peaceful night's sleep in pregnancy is challenging for many expecting Mum’s especially as your baby and belly continues to grow. From pregnancy insomnia, frequent toilet breaks and tossing and turning to find a comfortable position add having to sleep on your side into the mix and a full night's rest seems pretty much impossible. Side sleeping in pregnancy is so important for both the health of you and your baby. By allowing your uterus and placenta to continue to deliver oxygen to your baby. Research suggests that sleeping on your side during pregnancy reduces the risk of late-term stillbirth by 50% when compared to sleeping on your back. Knowing how to implement safe sleep habits throughout your pregnancy is essential.
Why do midwives recommend pregnant women to sleep on their side?
By now you’ve probably heard your midwife ask you 100 times if you are sleeping on your side. But have you ever understood why this is? In particular, why do we recommend sleeping on your left side? Here’s why:
The uterus: Your baby’s home throughout pregnancy.
In a non pregnant woman, the uterus has a blood flow of approximately 60 milliliters per minute. Compared to a pregnant woman at term (from 37 weeks) the uterus now has a 10 fold increase, requiring roughly 600 milliliters of blood per minute. (Krywko & King, 2023). So ensuring adequate blood flow to the uterus is essential for your baby’s well being, as even a small decrease in blood flow to this major organ can have negative effects on both maternal and fetal circulation. You can read more about these incredible body changes in our guide on second trimester body preparation.
Inferior Vena Cava:
Along your spine there is a major blood vessels known as the inferior vena cava (IVC). This vessel is responsible for transporting deoxygenated blood from the lower extremities and abdomen back to the right atrium of the heart (William, Tucker, Shrestha & Burns, 2023). Throughout pregnancy especially in the later trimesters, when in a supine position (on your back) the pressure of the uterus and your growing baby can compress this major blood vessel and therefore prevent blood flow back to the heart which can have negative effects on both you and your baby. When compared to an upright or sitting position, gravity prevents the uterus and baby pushing on the inferior vena cava. If this vessel is constricted it can cause a drop in your blood pressure leaving you with feelings of dizziness and nausea and limiting blood flow to the placenta to your baby which will ultimately reduce their oxygen levels. To understand the medical specifics of this, The Royal Australian College of General Practice provides a deep dive into how position impacts stillbirth risks.
The Placenta: Your baby’s oxygen tank.
The placenta is responsible for delivering nutrients and oxygen to your baby. It is also responsible for removing waste products. Ensuring optimal blood flow to the placenta is essential for adequate fetal oxygenation & growth.
So why is it encouraged to sleep on your left side?
It is recommended to sleep on your left side as the IVC is to the right of our spine and therefore laying on your left side prevents a reduction in blood flow to the uterus and placenta, encouraging optimal circulation for both you and your baby and reducing your risk of complications.
When should you be sleeping on your side?
It’s recommended to be sleeping on your side from 28 weeks pregnant. This includes naps during the day, whilst laying on the couch watching netflix and when sleeping overnight. This recommendation is emphasized as your pregnancy progresses especially in the third trimester. Typically it is safe to sleep on your back within the first and second trimester as your uterus & baby is not yet at a weight which could impede blood flow. However as your uterus continues to grow and the weight increases so does the risk of the uterus compromising blood circulation to your baby. Sleeping on your side, in particular your left side, is a proactive measure to support a healthy pregnancy.
Does it mean you always have to sleep on your left side?
While left side sleeping is generally recommended due to its positive impact on blood circulation, we are realistic in the way that for many women maintaining this position throughout the night may not be possible. If sleeping exclusively on the left side becomes uncomfortable, it’s okay if you find yourself on your right side. Utilising a pregnancy pillow to support your back and bump is beneficial to help achieve a restful night sleep, allowing you to comfortably change positions between left and right whilst preventing you from rolling onto your back.
What happens if you wake up on your back?
Don’t panic. It's not uncommon for pregnant individuals to wake up in a different position than how they fell asleep. This is normal. If you find yourself on your back all you need to do is roll over onto either your left or right side to resume the recommended position. Be reassured that our bodies are pretty amazing at recognizing if there is a decrease in circulation. For example a drop in blood pressure would make you wake up, which would then prompt you to change your position.
How can you safely sleep on your side?
Ensuring a safe and comfortable side sleeping experience involves implementing one simple thing…. investing in a Sleepybelly pregnancy pillow. Highly recommended by midwives and other women’s health experts, the Sleepybelly pregnancy pillow was designed to ensure safe sleep for pregnant mama’s. This versatile 3 piece pillow was created to support your bump, back & pelvis. With a long pillow designed to be placed behind your back this will take the worry away of waking up flat on your back, by providing support to assist you to sleep comfortably on your side. As well as having an adjustable pillow to tuck under your growing bump and an option to place a pillow between your knees this will help to provide relief to not only your abdomen but also your pelvis to help align the hips and reduce pressure to your lower back.
Embracing the practice of safe side sleeping from 28 weeks of pregnancy, particularly on the left side, will contribute to a healthier and more comfortable pregnancy for both you and your baby. If you ever have any concerns regarding your sleep, consulting your healthcare provider for personalised advice is essential to address individual circumstances and ensure the best possible care during this time.
Remember whilst the baby’s inside, sleep on your side.
If you're looking for a pregnancy pillow designed to prevent you from rolling onto your back you can take a look at the Sleepybelly here.
References:
Warland, J. (2017) Back to basics: avoiding the supine position in pregnancy. The Journal of Physiology. 595(4):1017-1018. doi: 10.1113/JP273705. PMID: 28198017; PMCID: PMC5309362.
Krywko, D., King, K.(2023) Aortocaval Compression Syndrome. https://www.ncbi.nlm.nih.gov/books/NBK430759/
