HRT is Contraindicated After Stroke
Hormone replacement therapy (HRT) should NOT be used in postmenopausal women with a history of stroke or TIA, regardless of the indication for treatment. This is a Class III recommendation (contraindicated) with Level A evidence from the American Heart Association/American Stroke Association 1.
Guideline-Based Absolute Contraindication
- The AHA/ASA explicitly states that postmenopausal hormone therapy (estrogen with or without progestin) is not recommended for women who have had ischemic stroke or TIA 1, 2
- This contraindication applies to all forms of systemic HRT, including oral estradiol, conjugated estrogens, and transdermal preparations 3
- The cardiovascular and cerebrovascular risks of estrogen apply regardless of the indication for its use—a history of stroke represents an absolute contraindication that supersedes any potential benefits 2
Evidence of Harm in Women with Prior Stroke
The Women's Estrogen for Stroke Trial (WEST) provides the most direct evidence for this population:
- No reduction in stroke recurrence or death over 2.8 years in women with prior stroke/TIA taking estradiol versus placebo 2, 4
- 2.9-fold increased risk of fatal stroke (HR 2.9; 95% CI 0.9-9.0) in the estrogen group 2, 5, 4
- Worse functional outcomes after recurrent strokes in women taking estrogen, with only 19% achieving complete recovery (NIHSS 0-1) compared to 33% in placebo group 6, 4
- Estradiol therapy should not be prescribed for secondary prevention of cerebrovascular disease 4
Additional Stroke Risk Data
- HRT may be harmful for secondary stroke prevention in postmenopausal women (Category 2 evidence) 1
- Meta-analysis of 28 trials showed a 29% increased rate of ischemic stroke with HRT (Number Needed to Harm = 147) 6
- Overall stroke risk increased by 24% (RR 1.24,95% CI 1.10-1.41) across primary and secondary prevention trials 7
- The absolute risk increase for stroke is 6 per 1000 women over approximately 4 years of treatment 7
Thromboembolic Risk Profile
Women with prior stroke face compounded risks on HRT:
- Venous thromboembolism risk nearly doubles (RR 1.92,95% CI 1.36-2.69) 7
- Pulmonary embolism risk increases 81% (RR 1.81,95% CI 1.32-2.48) 7
- Risk is highest in the first year of treatment 6
- FDA labeling explicitly warns that estrogens should be discontinued immediately if stroke or other arterial vascular events occur or are suspected 3
Critical Clinical Pitfalls to Avoid
- Do not assume vaginal estrogen is safe: While vaginal preparations have lower systemic absorption than oral formulations, some absorption still occurs and can increase circulating estradiol levels 5. The AHA/ASA contraindication applies to postmenopausal hormone therapy broadly 1, 2
- Do not be swayed by timing arguments: Even in women who start HRT less than 10 years after menopause (the "timing hypothesis"), those with prior stroke remain at increased risk of venous thromboembolism (RR 1.74,95% CI 1.11-2.73) 7
- Do not prescribe for any indication: The contraindication supersedes potential benefits for treating menopausal symptoms, osteoporosis prevention, or any other indication 2