Endometrial Biopsy Timing: Avoid Heavy Bleeding—Optimal Days 7–11 for Accurate Sampling

Endometrial biopsy samples the uterine lining to diagnose hyperplasia, cancer, or assess receptivity. Timing critically affects accuracy.

Why Avoid Heavy Bleeding

• Heavy menses = disordered, fragmented endometrium (breakdown phase).
• Sample may be insufficient, diluted with blood/clots, or show only necrotic debris.
• Increased procedural difficulty, pain, bleeding risk, and infection risk.
• Pathologist cannot reliably assess architecture or hormone effect.

Optimal Timing

• Proliferative Phase (Days 7–11 of 28-day cycle): Estrogen-driven growth; uniform glands, minimal stroma. Ideal for baseline architecture.
• Secretory Phase (Days 19–23): Progesterone effect; assesses ovulatory quality, dating (Noyes criteria), receptivity (IVF).

Clinical Workflow

1. Confirm patient not pregnant (urine hCG).
2. Schedule in early proliferative phase (post-menses, pre-ovulation).
3. If irregular cycles, use progesterone challenge or ovulation tracking to time.
4. Pre-procedure NSAID for cramping.

Proper timing ensures diagnostic yield and patient comfort.