DEFINING OPTIMAL CRITERIA TO INITIATE GNRH ANTAGONIST IN FLEXIBLE ANTAGONIST ICSI CYCLES

Background: This study was on infertile women who were experiencing ICSI procedure with flexible antagonist protocol aiming to help in determining optimal criteria to start antagonist inhibition for patients having rapid growth of follicles, or those with increased levels of estradiol E2, since, criteria when to initiate GnRH antagonist administration differ usually, The criteria chosen in this study were based on a collected information about reproductive physiology and also records from previous researches, hence, size of leading follicle, level of serum estradiol and also, serum LH level were used in current study to start antagonist administration, pregnancy rates were evaluated according to these various criteria. Materials and Methods: One hundred twenty infertile females were subjected to ICSI flexible antagonist protocol at the High Institute for Infertility Diagnosis and Assisted Reproductive Technologies/Al-Nahrain University from October 2020 to April 2022, inclusion standards were fresh transfer cycles and frozen cycles excluded also. Those patients were randomized in to three groups according to the criterion they justified to begin the antagonist, Group A: 40 patients where the antagonist was started when the leading follicle size was (12-14). Group B: 40 patients where the antagonist was started when the serum E2 was exceeding 500pg/ml and group C: 40 patients where the antagonist was started when the serum LH level > 5 IU/l. those patients were subjected to controlled ovarian hyper-stimulation using the flexible GnRH-antagonist protocol. Data were analyzed by (SPSS) version 26.0 using χ2, t-test, ANOVA, Fisher exact tests. Results: no significant difference in mean age among the three studied groups (p = 0.275), No significant difference among the three groups concerning the duration of infertility p value equal to (0.899). Regarding the type of infertility there were no significant differences among the three studied groups (p=0.163), there was also no statistical difference among the study groups concerning the cause of infertility (p=0.064). while there was significant difference in body mass index (BMI) among group A, B and C groups with p value equal to (0.022) with lowest value in group B (25.30± 2.93).. comparable basal hormonal levels of the study groups except for LH level, there was significant difference (p=0.049), also, a highly significant difference in LH levels among study groups at starting day of antagonist p< 0.001, furthermore, concerning data obtained at antagonist starting day, the difference was significant regarding the E2 levels P= 0.017, with higher levels of E2 and LH in group C, total gonadotropin dose among the three studied groups did not reach statistical significance, there was significant difference in the cycle day of antagonist initiation (p= 0.022) and the initiation was earlier in group A 6.65 ± 1.33, There was no significant difference in the duration of stimulation (days) and in number of antagonist ampoules total number of follicles at antagonist time was comparable a highly significant difference seen when the leading follicle size (LFS= 15) and (LFS= 16). While regarding day of ovulation trigger, the mean serum concentration of E2 and progesterone were comparable between the three time, However, mean serum concentration of LH was higher in group C with highly significant value (p value= 0.001), no significant difference among the three study groups regarding other stimulation characteristics. The difference was highly significant (P= >0.001) in pregnancy rate among the three different groups seen with highest percentage being in the B group 22(55%).