Clinical scenario

Sue, a 50-year-old woman, attends her GP with unexplained shortness of breath. Her background includes an uncomplicated appendectomy three weeks earlier. She has been using transdermal hormone replacement therapy (HRT) for over three years (estradiol 50 mcg patch with cyclical oral progestin) to manage perimenopausal symptoms.

She is referred to the Emergency Department, where imaging confirms bilateral pulmonary emboli (PE). These are classified as provoked, associated with recent surgery and hospitalisation. Risk stratification identifies her as low risk, with no right heart strain or biomarker elevation.

She is discharged on anticoagulation:

• Apixaban 10 mg twice daily for seven days; and
• Followed by 5 mg twice daily for three months.

Haematology advice indicates that HRT could be continued.

However, two months later, Sue re-attends her GP with heavy menstrual bleeding, night sweats, and low mood. She reports significant flooding. Her HRT had been stopped during admission, and there is hesitation to restart it without specialist confirmation.

 

Why this scenario matters

Venous thromboembolism (VTE), encompassing deep vein thrombosis (DVT) and PE, is a major global health burden and the third most common cause of vascular death. A significant proportion of cases are hospital-acquired, occurring during admission or within 90 days of discharge. The healthcare costs directly associated with VTE and hospitalisation are estimated to be €1.5 to €2.2 billion in Europe. For GPs, VTE represents both an acute diagnostic challenge and a longer-term management issue, particularly in relation to medication review and ongoing risk factors. This scenario highlights a frequent clinical dilemma in primary care: Should HRT be stopped or continued following a VTE?  

Recognising VTE in primary care

Timely diagnosis is critical. Key features include:

DVT:

• Unilateral leg swelling;
• Pain or tenderness to calf or thigh;
• Warmth and erythema; and

• Dilated superficial veins maybe present on examination.

PE:

• Unexplained breathlessness;
• Pleuritic chest pain;
• Tachycardia;
• Haemoptysis (suggesting higher risk);
• Unexplained collapse (poor prognostic indicator).

Risk factors for DVT or PE include:

• Hospital admission greater than 48 hours;
• Recent surgery;
• Lower limb immobilisation; and
• Prolonged immobility.

If any of these risk factors have occurred in the previous 90 days along with symptoms suggested above VTE needs to be excluded.

Risk factors are often cumulative. In Sue’s case, recent surgery and hospitalisation were the dominant transient triggers.

Other risk factors include oestrogen (i.e. combined oral contraceptive pill (COCP), oral hormone replacement therapy, (HRT), IVF, selective oestrogen receptor modulators (tamoxifen)) and antiphospholipid syndrome. A cancer diagnosis can also increase the risk of VTE four-fold, compared with non-cancer patients.

The role of oestrogen

Oestrogen exposure is a recognised risk factor for VTE, but the route and dose matter significantly.

• Combined oral contraceptives and oral HRT are associated with increased VTE risk; and
• Transdermal HRT (≤50 mcg) has not been shown to significantly increase VTE risk and is generally preferred in women with additional risk factors.

This distinction is crucial in guiding safe prescribing.

Should HRT be stopped after VTE?

Historically, oestrogen therapy was routinely discontinued following VTE. However, emerging evidence supports a more nuanced approach.

Key considerations:

• In patients who are therapeutically anticoagulated, oestrogen does not necessarily need to be discontinued. Anticoagulation mitigates thrombotic risk;
• Continuing HRT may reduce complications such as heavy menstrual bleeding and the recurrence of menopausal symptoms;
• If anticoagulation is to be stopped, oral oestrogen should be discontinued at least one month beforehand; and
• Transdermal HRT may be continued or restarted following an individualised risk assessment.

Interpreting Sue’s symptoms

Sue’s current symptoms are highly consistent with the consequences of unnecessary discontinuation of HRT combined with anticoagulation:

• Heavy menstrual bleeding (HMB): Likely multifactorial, due to apixaban, hormonal withdrawal, and underlying perimenopause;
• Vasomotor symptoms (night sweats): Classic rebound symptoms following abrupt cessation of oestrogen; and
• Low mood: Frequently associated with menopausal symptom relapse.

Importantly, the PE was clearly provoked by surgery. The transdermal HRT can continue.

Practical guidance in primary care

GPs play a central role in both the prevention and follow-up care of VTE. This includes:

1. Risk assessment:

• Identify transient and persistent risk factors; and
• Recognise that hospital admission and recent surgery are major triggers.

2. Medication review:

• Evaluate the type and route of oestrogen therapy; and
• Avoid unnecessary discontinuation of transdermal HRT.

3. Patient counselling:

• Educate patients on signs and symptoms of VTE; and
• Discuss risks and benefits of continuing HRT.

4. Post-discharge continuity:

• Clarify discharge plans promptly; and
• Liaise with secondary care if uncertainty exists.

Key takeaway for practice

In anticoagulated patients with provoked VTE, transdermal HRT can usually be safely continued or restarted.

Failure to do so can result in avoidable morbidity, including heavy menstrual bleeding, distressing menopausal symptoms, and reduced quality of life.

Further resources

• HSE National Clinical Guideline on Venous Thromboembolism (NCG – VTE) Eve Protocol: Available at www2.healthservice.hse.ie/files/534;
• National Clinical Programme for VTE: Available at healthservice.hse.ie > Information for healthcare professionals > Clinical Design and Innovation (CDI) > National Clinical Programme in Venous Thromboembolism;
• Educational video series: Available at youtube.com and search HSE “Blood clot information videos”; and
• IPU Professional Academy webinar recordings (available at ipuacademy.ie):
  • VTE Awareness, Assessment, Prevention & Management Spring 2026;
  • Medicines in Pregnancy, Autumn 2025;
  • Venous Leg Ulcers, Spring 2024; and
  • Atrial Fibrillation and Arrhythmias 2019.