As your pregnancy progresses, your blood volume increases by up to 50% and the weight of your uterus presses on the pelvic veins that return blood from your legs. The combination causes fluid retention, swelling (oedema), and the heavy, achy leg feeling that hits hardest in the third trimester.
It also raises the risk of deep vein thrombosis (DVT), which is why graduated compression is recommended for many pregnancies. Compression socks are a staple recommendation for managing this, but when it comes to choosing between knee-high and thigh-high lengths, many women find themselves stuck on which provides the best balance of comfort and relief.
Here is the breakdown of why each length serves a different purpose and how to decide which one is right for you.
1. Knee-High Compression Socks: The Daily Essential
Knee-high socks are the most common choice for pregnant women, and for good reason; they are generally the easiest to put on and the most comfortable for long-term wear.
The Pros: They focus on the area where gravity causes the most significant fluid pooling (the lower calf and ankle). They are less likely to roll down, they don't interfere with your bump, and they are much simpler to pull on as your flexibility decreases in the third trimester.
The Cons: They only provide compression up to the calf. If you experience significant swelling in your thighs or have visible varicose veins above the knee, these may not provide the full coverage you need.
2. Thigh-High Compression Socks: The Heavy-Duty Solution
Thigh-high compression socks provide support along the entire leg, which can be essential for women with more severe swelling or circulation issues.
The Pros: These socks address the entire venous system from the ankle to the upper thigh, which is particularly helpful if you suffer from thigh-level varicose veins or significant fluid accumulation in the upper leg.
The Cons: They are notoriously difficult to get on when your belly is growing. They also have a tendency to "roll" at the top band if the fit isn't perfect, which can create a tourniquet effect that actually restricts blood flow rather than improving it.
Which Should You Choose?
According to guidelines from Pregnancy, Birth and Baby, the "best" sock is the one that you will actually wear consistently.
Choose Knee-High if: You have mild swelling, you are struggling with the physical act of getting dressed, or you want a discreet option to wear under work clothes.
Choose Thigh-High if: You have been specifically advised by your midwife or a doctor to manage severe varicose veins that extend above your knee, or if you notice significant swelling in your quads and hamstrings.
A Note on "The Roll": The biggest complaint with thigh-high socks is the top band digging into the skin. If you choose this style, ensure you purchase a high-quality maternity-specific brand that features a "stay-up" silicone grip that is gentle on sensitive skin.
How Sleepybelly Can Help
At Sleepybelly, we focus on the total physical comfort of your pregnancy. Our Maternity Compression Socks are TGA-listed (ARTG 521641) and offer 15-25 mmHg graduated compression, tightest at the ankle and loosening as they move up the leg. This gradient is the gold standard for promoting venous return without feeling overly restrictive.
To maximise your comfort, we suggest a simple nightly wind-down routine:
Elevate & Recover: After a long day, spend 10–15 minutes with your legs elevated above the level of your heart to help drain fluid.
Soothe: Massage the Sleepybelly Magnesium Body Cream to your calves and feet to relax the muscles and soothe the skin after a day of compression wear.
Supportive Sleep: When you head to bed, remove your socks and shift into your Sleepybelly Pregnancy Pillow. Using the three-piece modular system to keep your legs slightly elevated while you sleep on your side can help prevent fluid from pooling overnight.
The Bottom Line
For most pregnant women, knee-high compression socks are the practical sweet spot. They provide the necessary support to combat ankle swelling without the struggle of fitting them over a growing bump or dealing with the discomfort of a band at the thigh. However, if your swelling or varicose veins are moving upward, thigh-highs are a valuable medical tool that, when fitted correctly, can make a world of difference.
The information in this article is general in nature and intended as comfort support only. It is not medical advice. Always consult your midwife, GP, or a qualified Australian healthcare professional before deciding on the level of compression that is right for your specific condition.
Why Compression Socks Are Recommended in Pregnancy
Pregnancy increases the risk of deep vein thrombosis (DVT) by roughly 4-5 times compared to non-pregnant women, with the risk staying elevated for around 6 weeks postpartum. The combination of higher blood volume, slower venous return, and the hormonal shifts that thicken the blood (a useful adaptation for childbirth, less useful for circulation) creates the conditions for clots to form, particularly in the calf veins.
Graduated compression socks help by physically supporting the venous walls and accelerating the return of blood from the legs to the heart. They're not a substitute for medical advice, especially if you have a personal or family history of clotting disorders, but for most women they're a low-risk, evidence-backed daily tool for managing the swelling and circulation challenges of pregnancy.
For more on DVT in pregnancy, HealthDirect has a comprehensive overview.
Compression Socks for Flying While Pregnant
Long flights amplify the same circulation challenges pregnancy already creates. Sitting still for hours in a low-cabin-pressure environment slows venous return, and pregnancy-related clotting risk compounds the effect. Most airlines and most obstetricians recommend graduated compression socks for any flight over 4 hours during pregnancy, ideally combined with regular aisle walks and good hydration.
Knee-high socks are usually the sensible choice for travel: easier to put on at the gate, comfortable for a full flight, and discreet under work clothes if you're flying for business. If you're flying long-haul (over 8 hours) and have a personal history of swelling or clotting, it's worth speaking to your midwife or GP about whether thigh-high is more appropriate for your specific journey.
Frequently Asked Questions
Are compression socks safe during pregnancy?
For most women, yes. Graduated compression socks (the kind that are tightest at the ankle and loosen up the leg) are widely recommended in pregnancy, including by HealthDirect. They're not advised for women with certain circulation conditions, so if you have peripheral artery disease or any clotting disorder, check with your GP or midwife before starting.
When should I start wearing compression socks during pregnancy?
Many women find them most useful from the second trimester onwards, especially if swelling has started. If you're flying, on your feet a lot, or have a family history of varicose veins or DVT, starting earlier is reasonable. There's no specific "correct" week to begin.
Can I sleep in compression socks during pregnancy?
Generally no. Compression socks are designed for upright wear when gravity is creating the venous return challenge. At night, lying flat already helps drain fluid back from your legs, and wearing compression for prolonged horizontal periods can be uncomfortable without adding benefit. The exception is if your healthcare provider has specifically recommended overnight wear for a clinical reason.
What level of compression is best for pregnancy?
For most pregnancy-related swelling, 15-25 mmHg (sometimes labelled "moderate" compression) is the standard recommendation. Higher compression should be fitted by a healthcare professional. Sleepybelly's Maternity Compression Socks are TGA-listed (ARTG 521641) at 15-25 mmHg, which sits squarely in this range.
Should I wear compression socks when flying while pregnant?
Yes, especially for flights over 4 hours. The combination of pregnancy-related clotting risk and prolonged sitting makes long flights one of the highest-risk circulation moments in a pregnancy. Pair compression socks with hydration, regular aisle walks, and ankle pumps in your seat.
