Let’s Talk About Blood Clot Risk: Dr Choong’s World Thrombosis Day Letter in the South China Morning Post

On World Thrombosis Day, 13 October 2026, the South China Morning Post published a letter from Dr Andrew Choong on blood clot risk in women. It appears as the second letter on this SCMP letters page, under the heading “Let’s talk about blood clot risk”. SCMP groups its letters under a single headline and the page may ask you to subscribe, so the letter is reproduced in full below, as published.

Let’s talk about blood clot risk

World Thrombosis Day falls on October 13. It is a good moment to talk about a risk most women are never told about clearly.

A clot in the deep veins of the leg, called deep vein thrombosis, can break off and lodge in the lungs as a pulmonary embolism, which can be fatal. It is less common in Asian than in Western populations, but reported rates across Asia have risen.

For women, the risk rises at specific, predictable points in life.

The first is contraception. Combined pills containing oestrogen raise the risk of a clot roughly three-fold. For a healthy young woman, the absolute risk remains small, so this is no reason to stop the pill. It is a reason for a proper conversation before starting it.

The second is pregnancy. Overall the risk is about four times higher than usual, and it peaks in the six weeks after birth. In Britain, blood clots are the leading cause of maternal death.

The third is menopause. Hormone therapy taken as tablets carries a raised clot risk; evidence suggests skin patches and gels do not carry the same risk.

At every stage the risk is raised further by a previous clot, a close relative who has had one, obesity, smoking, cancer, surgery or long periods of immobility such as a long-haul flight.

None of this should frighten women away from contraception, pregnancy or hormone therapy. It should prompt three things. Tell your doctor about any personal or family history of clots before starting hormones or when you become pregnant. Keep moving after childbirth or surgery and on long journeys.

And know the warning signs: swelling, pain, warmth or redness in one leg; sudden breathlessness; chest pain that is worse on breathing in; coughing up blood. A swollen, painful leg needs a doctor the same day. Breathlessness or chest pain is an emergency.

These symptoms are too easily dismissed, in pregnancy especially, as normal swelling or tiredness. A clot found early is very treatable. A clot missed can be fatal.

Dr Andrew Choong, vascular, endovascular and aortic surgeon

First published in the South China Morning Post, Letters, 13 October 2026. Reproduced by the author. Other media features and letters are collected on the In the Media page.

Where to read more

The deep vein thrombosis page explains how a clot in the leg is diagnosed with a duplex ultrasound scan, and the pulmonary embolism page covers what happens when a clot travels to the lungs. The DVT treatment page describes blood thinners, clot removal and when each is considered. For the two other World Thrombosis Day pieces this year, see Dr Choong’s Cambodianess article on clot prevention in hospital and the short video on DVT and PE warning signs.

Preparing for a vascular review

If you have had a swollen or painful leg, a clot in the past, or you are planning pregnancy or hormone therapy with a personal or family history of clots, a vascular review can establish whether the deep veins are affected and what, if anything, needs to be done. In Singapore, sudden breathlessness or chest pain means calling 995. To make an appointment, use the contact page; patients travelling from the region can read how to arrange a review on the international patients page.