What should I do if I experience vaginal bleeding after starting Hormone Replacement Therapy (HRT)?

Management of Vaginal Bleeding After Starting HRT

If you experience vaginal bleeding while on aromatase inhibitors (AIs) as part of your HRT, contact your physician immediately as this could indicate stimulation of ovarian function or other underlying issues requiring prompt evaluation. 1

Causes and Significance of Vaginal Bleeding on HRT

Vaginal bleeding after starting HRT is a common occurrence that often deters women from continuing or initiating therapy 2. The causes include:

• Normal breakthrough bleeding (especially during first months of therapy)
• Stimulation of ovarian function (particularly with aromatase inhibitors)
• Endometrial hyperplasia or carcinoma (requires exclusion)
• Structural abnormalities of the uterus

Evaluation Algorithm

1. Immediate Assessment:

   • Contact your physician immediately for any vaginal bleeding while on AIs 1
   • For other HRT regimens, report persistent or recurrent bleeding

2. Diagnostic Workup:

   • Physical examination with special reference to blood pressure, breasts, abdomen, and pelvic organs 3
   • Transvaginal ultrasonography to evaluate structural abnormalities 4
   • Endometrial biopsy if indicated (99.6% sensitive for detecting endometrial carcinoma) 4

3. Risk Stratification:

   • Higher risk: Persistent/heavy bleeding, risk factors for endometrial cancer
   • Lower risk: Light spotting in first few months of continuous combined HRT

Management Based on HRT Type

For Continuous Combined HRT:

• Expect some irregular bleeding/spotting during first year of therapy 5
• Bleeding typically decreases after 2 years of use 6
• Continue regimen if bleeding is light and evaluation is negative

For Cyclic/Sequential HRT:

• Bleeding should occur predictably during the progestogen phase
• Unexpected bleeding requires evaluation 3
• Monthly progestogen regimens have lower risk of endometrial hyperplasia than quarterly regimens 5

For Aromatase Inhibitors:

• Any bleeding requires immediate medical attention 1
• May indicate return of ovarian function in younger women

Important Considerations

• Unopposed estrogen significantly increases risk of endometrial hyperplasia (OR 5.4-15.0 depending on duration) 5
• Addition of progestogens (continuous or sequential) reduces hyperplasia risk 5
• Continuous combined therapy may cause more irregular bleeding in first year but less in subsequent years compared to sequential regimens 5, 6

Prevention Strategies

• Ensure adequate progestogen component in HRT regimen
• For non-hysterectomized women, never use unopposed estrogen
• Consider continuous combined HRT for long-term therapy as it has lower rates of unexpected bleeding after 2 years (22.3 vs 37.8 events per 100 patient-years) 6

When to Seek Urgent Care

• Heavy, persistent bleeding
• Bleeding that occurs after a period of amenorrhea on HRT
• Any bleeding while on aromatase inhibitors
• Bleeding accompanied by pain or other concerning symptoms

Remember that while breakthrough bleeding is common with HRT, it should never be assumed benign without appropriate evaluation to rule out serious underlying conditions.