Acute changes in endometrial thickness after aspiration of functional ovarian cysts

Objective: To evaluate the influence of aspiration of functional ovarian cysts on endometrial thickness. Design: Prospective study. Setting: An IVF Unit of an academic medical center. Patient(s): Twenty-two patients from our IVF program, in whom administration of a gonadotropin-releasing hormone agonist preparation in the 'long protocol' failed to induce pituitary desensitization, as evidenced by a serum E₂ concentration of >55 pg/mL and the presence of an ovarian cyst of >20 mm in diameter. Intervention(s): Transvaginal ultrasonographic-guided cyst aspiration was performed, and 2 days later, serum E₂ concentration and endometrial thickness were reassessed. Main Outcome Measure(s): The values of serum E₂ concentration and endometrial thickness before and after cyst aspiration were compared. Result(s): Two days after ovarian cyst aspiration, the serum E₂ concentration dropped from a mean (±SD) of 203 ± 93 to 37 ± 34 pg/mL. The mean (±SD) endometrial thickness was 9.6 ± 2.0 mm before cyst aspiration and decreased to 5.9 ± 2.4 mm after the procedure. Conclusion(s): Within 48 hours after ovarian cyst aspiration, a significant reduction in endometrial thickness occurs concomitant with a sharp decline in serum E₂ levels. The phenomenon of acute reduction in endometrial thickness in response to acute estrogen withdrawal has not been described previously. The exact mechanism and eadometrial component involved in the 'shrinking' process should be further investigated.