Combined down-regulation by aromatase inhibitor and GnRH-agonist in IVF patients with endometriomas—A pilot study

Abstract 

Objective

The key enzyme in the biosynthesis of estradiol, aromatase, has been demonstrated within endometriosis. Combined administration of aromatase inhibitor and GnRH-agonist may efficiently suppress estrogen biosynthesis through a combined pituitary, ovarian, peripheral and “in situ” action. The aim of this study was to test the concept of combined down-regulation prior to IVF in patients with endometriomas.

Study design

Prospective pilot study in a university-based tertiary fertility clinic including 20 infertile patients with endometriomas undergoing IVF/ICSI. The patients received goserelin 3.6mg sc on treatment Days 1, 28 and 56, and one daily tablet of anastrozole 1mg from Day 1 to Day 69. Controlled ovarian stimulation was initiated from Day 70. Outcome measures were change in endometriomal volume and serum CA125 during down-regulation, standard IVF parameters including pregnancy and delivery rate, and endocrine response. The paired T test and Wilcoxon Signed Rank test were used to analyse paired differences.

Results

During the combined down-regulation, the endometriomal volume and the serum CA125 level decreased by 29% (3–39%) and 61% (21–74%), respectively (median (95%CI), P=0.007 and P=0.001). In the IVF/ICSI cycle, the number of oocytes retrieved was 7.5 (6.0–10.0) and the fertilization rate was 0.78 (0.38–1.0). Nine patients (45%) conceived, five (25%) had a clinical pregnancy, and three (15%) delivered healthy children (two singletons and one twin).

Conclusions

Prolonged combined anastrozole and goserelin down-regulation significantly reduces endometriomal volume and serum CA125, and is compatible with IVF pregnancy and delivery. However, a high pregnancy loss was noted.

Keywords: Aromatase inhibitor, Down-regulation, Endometrioma, GnRH-agonist, IVF