P-636 Use of Desogestrel as an alternative to GnRH antagonists to inhibit the LH surge: a prospective randomized controlled observational study
Authors: Lorenzo F , Young Obejero E , Valcarcel A , Garcia Ojeda B , Luzuriaga M 
Published: June 2022

Abstract

Study question
To describe whether desogestrel is as effective as GnRH antagonists in inhibiting the LH surge during controlled ovarian stimulation.

Summary answer
We conclude that although we can obtain fewer oocytes,desogestrel is effective as GnRH antagonists to inhibit the LH surge during controlled ovarian stimulation.

What is known already
It is known that ovarian secretion of progesterone has the ability to modulate the secretory pattern of LH of a natural menstrual cycle. Because exposure to high levels of progesterone can generate a phase shift between embryonic development and endometrial receptivity, this was not an option when performing HOC in conventional IVF-ICSI. New technologies and constant advances in vitrification techniques for both gametes and embryos have allowed us to think of different strategies when performing a HOC. This is why a new concept, progestagen priming, was introduced as a safe and comparable alternative to conventional ovarian stimulation with GnRH antagonists.

Study design, size, duration
We conducted a prospective, observational, randomized, controlled study at our institution IFER affiliated with the University of Buenos Aires, from August 2020 to December 2021. A total of 74 patients were included. Our main objective was to evaluate the efficacy of desogestrel as an LH surge inhibitor in patients undergoing egg donation, medical and social fertility preservation, and controlled ovarian stimulation without fresh embryo transfer.

Participants/materials, setting, methods
Patients under 39 years of age who underwent controlled ovarian stimulation for egg donation cycles, fertility preservation for medical and social reasons, and IVF-ICSI cycles without fresh transfer (risk of OH,PGS) The patients were separated into two groups. Both groups received conventional HOC.In the DESOGESTREL group received 75mg/day from the start of stimulation to the day of CGH, in the control group, received antagonists 0.25mg/day with follicles 14 mm until the day of CGH.ther parameters

Main results and the role of chance
We divided the Desogestrel Goup : &gt; 35-35 y (GI) 32 p, 36-39 y (GII) 42p, Control Group : 35-35 y (GIII) 29 p,36-39 y (GIV) 45p. total dose of gonadotrophins used: GI: 1600 UI ± 300 UI, GIII: 1800 UI ± 400 UI ( NS) GII:1900 UI ± 400 UI, G IV : 2200 UI ± 400 UI (NS).Length of HOC: G I: 12 d ± 2 , G III: 13 d ± 2, G II: 14 d ± 2 , G IV: 15 d ± 2 ( NS). MII retrieved: GI: 10 ±3, GIII: 12± 3 (NS), GII : 7± 3, G IV: 7± 2 ( NS).The number of oocytes obtained may be a little lower than those obtained in the control group, but not statistically significant, the same as in the number of doses of gonadotrophins used, nor in the number of days of stimulation.

Limitations, reasons for caution
Size of study group

Wider implications of the findings
Although the study group is small, we have shown that the use of desogestrel is similar shown with the use of other gestagens during COH. We believe that desogestrel is a patient-friendly alternative due to its route of administration, price, and longer half-life, compared to antagonist analogs.

Trial registration number
NA