P-602 Ovarian stimulation without LH suppression in the freeze-all era
Authors: Gurbuz A S , Gurbuz Z U 
Published: June 2023

Abstract

Study question
Can controlled ovarian stimulation be performed without LH suppression in the freeze-all era?

Summary answer
The oocyte and embryo quality in patients who were treated with freeze-all cycles is not affected without LH suppression.

What is known already
The LH suppression is a crucial part of the controlled ovarian stimulation in fresh IVF cycles. It is generally accepted that prolonged or premature exposure to LH can cause early progesterone secretion and abnormal oocyte maturation. Several agents such as GnRH agonists, antagonists and progestins have been used for LH suppression. Recently, different protocols such as duostim, luteal phase stimulation, random start stimulation have been developed in parallel with the widespread application of the freeze-all strategy. No decrease was observed in the quality, maturation and fertilization of oocytes obtained in these protocols.

Study design, size, duration
This study was retrospectively performed, with cycles extracted from freeze-all-IVF treatments performed between May 2022 and January 2023, to compare the efficacy of ovarian stimulations with or without LH suppression. LH suppression cycles were matched 1:1 with only gonadotropin cycles using age, BMI and antral follicle count, resulting in 160 matched foIIowed by IVF or ICSI with the freeze-aII strategy. The primary outcome of the triaI was the number of oocytes and mature oocytes retrieved.

Participants/materials, setting, methods
The patients were evaluated in 2 groups as the only gonadotropin (rec FSH- study group) or antagonist protocoI (rec FSH+cetroreIix- control group). The rec-FSH was administered at the second or third day of menstrual cycIe in both groups. The cetroreIix was started when the leading follicle was 13mm or more in the control group. Oocyte maturation was triggered by hcg or with GnRH agonist ( triptoreIin). AII viable embryos were cryopreserved for frozen embryo transfer.

Main results and the role of chance
Basic characteristics in both groups were simiIar. There was no significant difference in the number of oocytes (11.87±6.22.3 (mean±SD) for the study group versus 13.47±7.69 for the control group, (P = 0.14)) or the mature oocytes retrieved (8.46±4.8 for the study group versus 9.78±6.3 for the control group, (P = 0.13)) between the groups. The number of fertilized oocytes did not differ between the two groups (6.67±4.6 for the study group vs 7.56±5 for the control group). The mean progesterone LeveL at trigger day in the only rec FSH group was higher than that in the rec FSH+ Cetrorelix group (1.71±1.37 for the study group vs 1.35±0.5 for the control group P = 0.03). No patients experienced ovarian hyperstimuIation syndrome.

Limitations, reasons for caution
Main Iimitation of this study is, that it is retrospective. Another limitation is that this study includes number of oocytes, mature oocytes and fertilization rate solely. The cIinicaI pregnancy rates and Iive birth rates were not determinated in the freeze-all cycles due to the short duration of the study.

Wider implications of the findings
LH surge and elevation of progesterone do not have negative effects on oocyte quality and maturation. Ovulation induction can be performed without LH suppression in freeze-all cycles. Undoubtedly, there is a need for new studies investigating the effects of only gonadotropin administration on live birth rates in frozen-thawed embryo transfers.

Trial registration number
Not applicable