Leg Pain and Blood Clots After Birth

When to call

Call 999 or go to A&E if you have leg pain and swelling and you also feel short of breath or have chest pain. That is the NHS threshold. It says why: "DVT can be very serious because blood clots can travel to your lungs. This is called a pulmonary embolism. A pulmonary embolism can be life-threatening and needs treatment straight away." The NHS also says not to drive yourself.

Ask for an urgent GP appointment or get help from NHS 111 if you think you have a DVT. If you have a maternity unit number, the NHS says you can call that too. Do not wait for your next routine postnatal visit.

The HSE in Ireland lists it in the same urgent category: contact a GP, midwife or public health nurse immediately if "you have pain in your calf that does not go away — this could be a sign of a blood clot."

What a DVT feels like

The NHS symptom list for a DVT in the leg:

• throbbing pain in 1 leg (rarely both legs), usually in the calf or thigh;
• swelling in 1 leg (rarely both legs);
• red, blue or darkened skin around the painful area — the NHS notes this "may be harder to see on brown or black skin";
• swollen veins.

The word doing the work there is one. Both ankles puffing up after birth is extremely common and is not what this page is about. One calf that is sore, tight, warm and visibly bigger than the other is different.

The NHS adds a rarer presentation that matters after birth: "Sometimes the only symptom you may have is pain in your lower tummy. This is a symptom of pelvic vein thrombosis, but this is rare."

Why the risk peaks now, not in pregnancy

This is the fact that surprises people. The RCOG patient information on venous thrombosis states: "Pregnancy increases your risk of a DVT, with the highest risk being just after you have had your baby."

The same leaflet gives the scale honestly, and it is reassuring: "venous thrombosis is still uncommon in pregnancy or in the first 6 weeks after birth, occurring in only 1–2 in 1000 women."

The NHS lists "are pregnant or if you've had a baby in the previous 6 weeks" among the times when your chance of a DVT is higher, alongside recent surgery, a hospital stay where you could not move around much, being confined to bed for three days or more, dehydration, and long journeys over four hours.

What pushes your risk up further

The RCOG names factors including a very long labour of more than 24 hours, a caesarean section, losing a lot of blood after birth, or receiving a blood transfusion. Severe varicose veins that are painful or above the knee with redness and swelling are also on its list.

The NHS adds being over 60, overweight or obese, smoking, a previous DVT, thrombophilia, cancer, heart failure, inflammatory bowel disease and vasculitis. It also notes: "Sometimes DVT can happen for no obvious reason."

The heparin injections, and why they carry on at home

The RCOG explains that you will have a risk assessment after birth as well as during pregnancy: "Even if you weren't having injections in pregnancy, you may need to start heparin injections for the first time after birth. This will depend on what risk factors you have for a DVT. You may be advised to have heparin for 7-10 days after birth or sometimes for 6 weeks after birth."

If you were already on heparin before the birth, the RCOG says "you are likely to be advised to continue this for 6 weeks afterwards."

NICE NG194 points clinicians to the NICE venous thromboembolism guideline and the RCOG guideline for assessing and preventing clots in women who have given birth. If you were given injections and sent home with a sharps bin and no explanation, this is what they are for — and finishing the course matters more than it feels like it does when you are well.

If it is a pulmonary embolism

The NHS symptoms of a pulmonary embolism are difficulty breathing that comes on suddenly, chest pain that is worse when you breathe in, and coughing up blood. It adds that you may also have pain, redness and swelling in one leg.

Call 999 for severe difficulty breathing, pain in the chest or upper back, a very fast heartbeat, or if someone passes out. The NHS is direct about the outlook when it is caught: "You should make a full recovery from a pulmonary embolism if it's spotted and treated early."

NICE NG194 puts both on the list of things it tells midwives to warn you about at your first postnatal contact: "leg swelling and tenderness, or shortness of breath, which could indicate venous thromboembolism," and "chest pain, which could indicate venous thromboembolism or cardiac problems."

What actually lowers your risk

The RCOG's advice after birth is unglamorous: "It is important to be as mobile as possible after you have had your baby and to avoid becoming dehydrated." The NHS agrees — stay active, walk regularly, drink plenty of fluids. If you are recovering from a caesarean, that means short frequent moves around the house rather than a walk you have to be brave for.

What to say on the phone

"I gave birth [x] weeks ago, and one of my calves is painful and swollen." The postnatal detail changes the urgency of the answer, and after a birth it should. If breathlessness or chest pain is part of it, you are not ringing the GP — you are ringing 999.