Somewhere around week 30, most women stop being able to wear their normal shoes. Feet and ankles swell, socks leave a ring, rings stop coming off, and by evening your feet look like they belong to someone else. Swelling — oedema — is one of the most common things pregnancy does to the body, and the overwhelming majority of it is harmless plumbing.
The catch is that swelling is also the visible edge of two conditions that are not harmless at all. This guide covers why it happens, what genuinely reduces it, the advice that gets repeated but does not work, and the three patterns that mean you stop reading and pick up the phone.
The short answer: gradual swelling of both feet and ankles that is worst in the evening and better by morning is normal pregnancy oedema. Reduce it by lying on your left side with your feet above heart level, wearing graduated compression stockings from first thing in the morning, moving regularly rather than standing or sitting still, and staying well hydrated. Call your midwife the same day if swelling appears suddenly, involves your face or hands, comes with a headache or vision changes, or affects one calf that is painful, warm or red.
Why pregnancy swells your feet
1. There is far more fluid in you
Blood volume rises by roughly 40–50% during pregnancy, and the plasma component rises more than the red cell component. Your body is also holding onto more sodium and water overall. That extra fluid has to go somewhere, and some of it sits in the tissues.
2. The return journey is blocked
Blood gets back to the heart from your legs against gravity, helped by the calf muscles squeezing the veins. By the third trimester the uterus is pressing on the inferior vena cava and the pelvic veins, raising the pressure downstream. Fluid leaks out of the capillaries into the surrounding tissue and pools at the lowest point available, which is your feet.
3. Your blood vessels are deliberately leakier
Progesterone and relaxin loosen smooth muscle throughout the body, including vessel walls, and the concentration of protein in your blood falls slightly during pregnancy. Both make it easier for fluid to cross out of the bloodstream. This is normal physiology, not a fault.
Heat, long days on your feet, long-haul flights, standing jobs and sitting still all make it worse, which is why late-pregnancy summer is nobody's favourite.
What normal swelling looks like
✅ Reassuring signs
- It came on gradually, over weeks, not overnight
- Both feet and ankles are affected roughly equally
- It is worst in the evening and much better after a night's sleep
- It gets worse in heat and after standing
- Your face and hands are unaffected, or only mildly so
- There is no pain, redness or warmth
- Your blood pressure is normal at your antenatal checks
A dent that stays for a few seconds when you press your thumb into your shin — pitting — is normal in pregnancy and does not by itself mean anything is wrong.
What actually reduces it
Try this first: lie on your left side with your feet propped above the level of your heart for 20 minutes, two or three times a day. Left-side lying moves the uterus off the vena cava; elevation lets gravity do the draining. Together they outperform every other measure on this page.
Compression stockings, put on at the right time
Graduated compression stockings are the intervention with the best evidence, and the timing is the part people get wrong. Put them on before you get out of bed in the morning, when your feet are at their smallest — pulling them onto already-swollen feet is both harder and much less effective. Class 1 compression is the normal starting point. Take them off at night.
Water immersion
Standing or gently walking in a swimming pool for 20–30 minutes reduces swelling more than most people expect. The water pressure pushes fluid out of the tissues and back into circulation, and it does it without any effort from you. Swimming is also one of the best exercises left available in late pregnancy — see our safe exercise guide.
🦶 Everyday habits that help
- Ankle circles and foot flexes — 10 each way, every hour you are sitting
- Never stand still for long — walking is much better for swelling than standing
- Do not cross your legs when sitting
- Sleep on your left side — the same principle, applied for eight hours
- Drink 2–2.5 litres a day — dehydration makes the body retain more, not less
- Wider, flatter shoes with a proper sole; go up a size without guilt
- Take rings off early, before they stop coming off at all
- Keep cool — cool foot baths, and avoid the hottest part of the day
- On flights and long drives, walk every hour and wear compression
Sleeping position does double duty here, since left-side lying also helps reflux and back pain. Our pregnancy sleep positions guide covers the pillow arrangement that makes it sustainable.
Advice that does not work
- Cutting salt drastically. Old advice, now reversed. Severe sodium restriction does not reduce pregnancy oedema and can be counterproductive. Normal seasoning is fine; cutting heavily processed food is worth doing for other reasons.
- Drinking less. Backwards. A dehydrated body holds onto fluid harder.
- Water tablets (diuretics). Not appropriate for physiological pregnancy swelling, and potentially harmful by reducing the plasma volume the placenta depends on. Only ever on a doctor's specific prescription.
- Tight socks or non-graduated compression. A tight band at the ankle or calf traps fluid below it. Graduated stockings are tightest at the ankle and loosen upward, which is the opposite design.
- Vigorous massage of a swollen calf. Gentle upward stroking is fine for general puffiness, but never massage a calf that is painful, warm or swollen on one side — see below.
The three patterns that need a call
Call your midwife, maternity triage or your emergency number the same day if: swelling comes on suddenly or affects your face and hands; one calf is swollen, painful, warm or red; or swelling comes with breathlessness or chest pain.
1. Sudden swelling of face and hands — possible pre-eclampsia
Pre-eclampsia affects a small but significant minority of pregnancies and is a leading cause of serious complications for both mother and baby. Swelling is not how it is diagnosed — that needs a blood pressure reading and a urine test — but a sudden change in the pattern of your swelling is a recognised warning. Get checked the same day if you notice:
- Swelling that appears suddenly rather than building over weeks
- Puffiness of the face, around the eyes, or the hands rather than just the feet
- A severe headache that paracetamol does not touch
- Visual disturbance — flashing lights, blurring, spots
- Pain just below the ribs on the right side
- Sudden weight gain of more than about 1kg in a week
- Vomiting in late pregnancy
2. One swollen calf — possible deep vein thrombosis
Pregnancy raises the risk of a deep vein thrombosis (DVT) roughly four to five times, and the risk stays elevated for six weeks after birth. The distinguishing feature is asymmetry: normal pregnancy swelling affects both legs, a clot affects one. Treat as urgent, do not massage it, and do not wait until morning if:
- One calf or thigh is noticeably more swollen than the other
- Pain or tenderness in one calf, often worse when standing or walking
- Warmth or redness over the area
- The skin looks stretched, shiny or discoloured
3. Swelling with breathlessness or chest pain — emergency
Call 999, 911 or your local emergency number immediately for sudden breathlessness, chest pain, coughing up blood, or a racing heart alongside leg swelling. This can indicate a clot that has travelled to the lungs. Breathlessness on climbing stairs in late pregnancy is common and not what this means; sudden breathlessness at rest is.
Our pregnancy symptoms A–Z lists which other late-pregnancy changes are routine and which are not.
Swelling after the birth
Most women are surprised that swelling often gets worse for the first three to five days postpartum. Fluid given during labour, the sudden release of pressure on the vena cava, and hormonal shifts all contribute. It then resolves over one to two weeks as your body sheds the excess, usually with heavy night sweats and a lot of urination.
What can persist is shoe size. Relaxin loosens the ligaments supporting the arch of the foot, and for some women the arch stays slightly flattened afterwards, leaving them permanently half a size larger. Our postpartum recovery guide covers the full six-week picture, including why the DVT warning signs still apply after delivery.
FAQ — Swollen feet in pregnancy
When do swollen feet usually start in pregnancy?
Most women first notice it from around week 22, and it builds through the third trimester as blood volume peaks and the uterus presses harder on the pelvic veins. It is typically worst in the evening, in hot weather, and after a long day of standing or sitting. Swelling that appears suddenly, rather than building gradually, is the version that needs checking.
How can I reduce swollen feet during pregnancy fast?
Lie on your left side with your feet raised above heart level for 20 minutes. That combination takes the weight of the uterus off the vena cava and lets gravity drain the fluid, and it works faster than anything else. Compression stockings put on before you get out of bed prevent the swelling building in the first place, and 20 minutes standing in a swimming pool is remarkably effective.
Should I cut down on salt or drink less water?
No to both. Severely restricting salt does not reduce pregnancy swelling and is no longer advised. Drinking less water makes it worse, because a dehydrated body retains more fluid, not less. Aim for normal seasoning and 2 to 2.5 litres of fluid a day. Cutting back on heavily processed food is worth doing, but that is about the food, not the salt shaker.
Is swelling in one leg only a problem?
Yes, treat it as urgent. Normal pregnancy swelling is symmetrical. One calf that is swollen, painful, warm or red can be a deep vein thrombosis, and pregnancy raises clot risk about four to five times. Do not massage it, do not wait to see if it settles overnight, and contact maternity triage or your emergency number the same day.
When does swelling mean pre-eclampsia?
When it comes on suddenly, affects the face, around the eyes or the hands rather than just the feet, and comes with a headache, visual disturbance, upper-right abdominal pain or a sudden weight jump. Pre-eclampsia is diagnosed by blood pressure and urine protein, not by swelling itself, so the action is always to get checked rather than to judge it yourself.
Will my feet go back to their old size after birth?
The swelling does, usually over one to two weeks as your body sheds the extra fluid, often with a few nights of heavy sweating and frequent urination. Swelling can briefly get worse in the first few days after delivery, which surprises most people. Shoe size, though, sometimes stays permanently up by half a size, because relaxin loosens the ligaments in the arch of the foot.
Are compression stockings safe in pregnancy?
Yes, and they are one of the few things with good evidence behind them. Class 1 graduated compression is the usual starting point. Put them on before you get out of bed, while the swelling is at its lowest, and take them off at night. If you need a firmer class or have varicose veins, ask your midwife to measure and advise.
Can I take anything for swelling in pregnancy?
Diuretics, or water tablets, are not appropriate for ordinary pregnancy swelling and should never be taken unless a doctor has prescribed them for a specific condition. There is no safe over-the-counter treatment. Elevation, compression, movement and water immersion are the interventions that work, and paracetamol is fine for aching feet, though ibuprofen and other NSAIDs are not after 20 weeks.
Swollen feet in pregnancy — at a glance
Swollen feet and ankles are caused by a 40–50% rise in blood volume, a uterus pressing on the veins that drain your legs, and blood vessels that are deliberately leakier during pregnancy. Gradual, symmetrical swelling that is worst in the evening and better by morning is normal. Bring it down by lying on your left side with your feet above heart level, wearing graduated compression stockings put on before you get out of bed, moving regularly, spending time in a pool, and drinking properly rather than less. Do not cut salt drastically and never take water tablets. Sudden swelling, facial or hand puffiness, one painful calf, or swelling with breathlessness all need a same-day call. Most swelling resolves within two weeks of birth, though shoe size sometimes does not.
Inside Baby Novum: the swelling tracker rates hands, feet and face separately with optional photos so you can see the pattern change over time, and the blood pressure log sits alongside it — the two readings your midwife will ask about together.