Estradiol Pretreatment in an Ultrashort GnRH Combined with a GnRH Antagonist Protocol in A Cohort of Poor Responders Undergoing IVF/ICSI: A Case-control Study.

AIM To provide results of the use of estradiol pretreatment in a combination of an ultrashort gonadotropin-releasing hormone (GnRH) agonist and antagonist protocol, in an attempt to improve the clinical outcomes in "poor responders", according to the Bologna criteria, undergoing in vitro fertilization (IVF). PATIENTS AND METHODS We applied estradiol pretreatment to 20 participants before the initiation of a combination of an ultrashort GnRH agonist plus an GnRH antagonist protocol followed by high doses of gonadotropins; the control group consisted of 20 subfertile participants with matching age, body mass index (BMI), basal follicle-stimulating hormone (FSH) and anti-Müllerian hormone (AMH), antral follicle count (AFC) and cause of subfertility, conforming with the same inclusion criteria and treated with a fixed GnRH antagonist protocol. The primary outcome measure was live birth, while the secondary outcomes included embryological and cycle parameters. RESULTS Live birth was determined in reduced rates in the study compared to the control group (0/20 vs. 3/20, p=0.231) as also in the respective number of clinical pregnancies (2/20 vs. 5/20, p=0.407) and cancellations (10/20 vs. 6/20, p=0.197), but none of these differences reached statistical significance. Also, most of the secondary parameters studied were similar for both groups. CONCLUSION The study protocol does not seem to constitute an equally effective method compared to the GnRH antagonist protocol in the selected study population. The presented dissimilar results with those reported so far in the literature are possibly attributed to the small sample size and the strict criteria applied when labeling participants as "poor responders".