If you have been searching for ways to manage swollen ankles or prevent varicose veins, you’ve likely come across the term "mmHg." This stands for millimetres of mercury, and it is the standard unit used to measure the pressure level of compression garments.
Choosing the right level is essential; too little and you won't feel the benefits, too much and you could restrict your circulation. For the vast majority of healthy pregnancies, mild to moderate compression is the safe and recommended standard.
A quick note before we get into the numbers. Deciding which level is right for you, especially if you're considering stepping up to a firmer pressure, is the kind of conversation worth having with your midwife. We often point our community to Amber at Body Birth and Baby (https://www.instagram.com/bodybirthandbaby), whose practice sits at the intersection of pregnancy comfort and everyday wellness, exactly the territory compression socks live in.
Understanding the Compression Scale
Compression levels are categorised into "Classes" based on the amount of pressure they apply at the ankle.
1. 15-20 mmHg (Mild / Over-the-Counter)
This is the most common and widely recommended level for expectant mothers. Many women find this level provides gentle, supportive pressure throughout the day, and it doesn't require a medical prescription.
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Best for: Daily wear to prevent "heavy legs," reducing minor evening swelling, and long-distance travel.
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Safety: Very high. This level is generally considered safe for all healthy pregnant women.
2. 20-30 mmHg (Moderate / Medical Grade)
This is a firmer level of compression often used when symptoms are more pronounced.
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Best for: Managing existing varicose veins, significant oedema (swelling), or as directed by an Australian healthcare professional to prevent Deep Vein Thrombosis (DVT).
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Safety: High, but it is best to consult your midwife or GP before moving up to this level to ensure your blood pressure and arterial health are optimal.
3. 30-40 mmHg+ (Firm / Prescription Only)
Levels above 30 mmHg are generally reserved for severe medical conditions such as chronic venous insufficiency or active blood clots. These should only be worn under strict medical supervision.
Why Graduated Compression is Key
It isn't just about the mmHg number; it’s about how that pressure is distributed. Safe maternity socks must be graduated. This means the pressure is strongest at the ankle (where gravity causes blood to pool) and gradually decreases as the sock moves up the leg.
Pregnancy, Birth and Baby (https://www.pregnancybirthbaby.org.au/varicose-veins) notes that compression stockings are part of the standard recommendation for managing the venous changes that come with pregnancy. Without this gradient, a sock could actually "trap" blood in the lower leg, which is exactly what we want to avoid.
How Sleepybelly Supports Your Circulation
At Sleepybelly, we designed our Maternity Compression Socks with a safe, effective 15-20 mmHg graduated pressure, and they're TGA-listed as a Class I medical device (ARTG 521641). This level is suited to the daily demands of pregnancy, providing relief whether you're on your feet all day or sitting at a desk.
To maximise your leg health, we suggest a holistic approach:
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Wear Early: Put your socks on first thing in the morning before swelling has a chance to start. For more tips on what to pack for the big day, check our What to Take to Hospital Checklist.
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Combine with Magnesium: At the end of the day, remove your socks and massage Sleepybelly Magnesium Body Cream into your calves. This helps relax the muscles that have been working hard all day.
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Sleep Aligned: Use the Sleepybelly Pregnancy Pillow to settle into side-lying for the night. Daytime compression keeps fluid moving while you're upright; overnight, the pillow does a different job, holding you in a position that doesn't kink the pelvic veins, so circulation has the easiest possible route while you rest.
For more information on managing vein health, Healthdirect Australia offers comprehensive advice on identifying and treating varicose veins. For a deeper dive into how compression socks fit into pregnancy and postpartum, our Compression Socks for Pregnancy & Postpartum 2026 Guide is worth a read.
Frequently Asked Questions (FAQ)
Q: Can I wear compression socks to sleep?
A: Generally, no. Compression socks are designed for use when you are upright and fighting gravity. When you are lying flat, your circulation doesn't need the same assistance. Use the Sleepybelly Pregnancy Pillow to elevate your legs slightly instead.
Q: How do I know if my socks are too tight?
A: If you experience numbness, tingling, or a change in the colour of your toes, remove the socks immediately. They should feel like a "firm hug," not a painful squeeze.
Q: Are they safe for air travel?
A: Yes, they are highly recommended! We've detailed the benefits in our guide to Maternity Travel Essentials.
The Bottom Line
For most pregnant women, a 15-20 mmHg graduated compression sock is the "sweet spot" for safety and effectiveness. It provides the necessary support to combat swelling and prevent vein issues while remaining comfortable enough for all-day wear.
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 healthcare provider for guidance specific to your situation.
