When a blood clot breaks loose and travels in the blood, this is called a venous thromboembolism (VTE).
An embolism is a condition where the blood flow in an artery is blocked by a foreign body, such as a blood clot or an air bubble.
To function properly, the body's tissues and organs need oxygen, which is transported around the body in the bloodstream. If the blood supply to a major organ - such as the brain, heart or lungs - is blocked, the organ will lose some or all of its function.
HRT tablets (but not patches or gels) are linked with a higher risk of developing a blood clot.
If you are already at higher risk of blood clots (for example, you are obese) and you are considering HRT, you may be offered patches or gel rather than tablets.
If you have a strong family history of blood clots or if there's another reason why you are at high risk of blood clots, you may be referred to a haematologist (a doctor who specialises in blood conditions) before considering HRT.
Not all HRTs have the same effect on your body. Speak to your healthcare professional about the risks and benefits of taking HRT, and which one would be most suitable for you as an individual.