P-646 The effect of profound LH suppression in GnRH antagonist cycles on IVF/ICSI outcomes-A retrospective study of 400 cycles

Abstract Study question Does low pretrigger LH in GnRH antagonist cycles affect the blastulation rates and cumulative live birth rates? Summary answer Low pretrigger LH in GnRH antagonist cycles does not affect the blastulation rates and cumulative live birth rates in frozen embryo transfer cycles. What is known already • There is conflicting evidence that in GnRH antagonist cycles stimulated with recombinant FSH, low serum LH may effect negatively the pregnancy outcomes in fresh embryo transfer.(Benmachiche et al 2019). • Whether the observed effect of low LH is on the embryo or on the endometrial receptivity is not clear. Study design, size, duration • Retrospective observational single centre study with a study population of 400 undergoing IVF/ICSI in between December 2018- December 2021. • Controlled ovarian stimulation in GnRH Antagonist protocol in unselected population > 21yrs old undergoing IVF/ICSI. • Exclusion Criteria- • Long protocol • Flare protocol • Oocyte cryopreservation cycle • Donor oocyte cycle Participants/materials, setting, methods • Controlled ovarian stimulation is done according to the hospital’s standard operations of practice in flexible antagonist cycle with human menopausal gonadotropins and recombinant/urinary follicle stimulating hormone. • When 3 or more follicles >/=17mm, triggered with GnRH Agonist or dual trigger. • Oocyte pick up scheduled at 35-36hrs following trigger. • Serum LH measured at baseline and at trigger. • Clinical and embryological outcomes are assessed in between low serum LH i.e., <1.5MIU/ML and normal serum LH >/= 1.5 MIU/ML. Main results and the role of chance Demographic variables were comparable between both the arms, except that baseline LH is low in subjects with low pretrigger LH. Mean dose of gonadotropins although not statistically significant, is slightly higher in the low pretrigger LH group. Mean duration of stimulation is higher in low pretrigger LH group and is statistically significant. Mean number of oocytes retrieved, mature oocytes, fertilisation rate, number of blastocysts, day5 and day6 blastocyts, good quality blastocysts and cumulative live birth rates are similar between low pretrigger LH and normal pretrigger LH group. Outcomes between low pretrigger LH and normal pretrigger LH- Mean number of blastocysts- 5.02 +/-3.84 vs 4.72 +/-3.82 (p = 0.44) Mean number of day5 blastocysts- 4 (0-14) vs 3.5(0-20) (p = 0.86) Mean number of day6 blastocysts- 1 (0-8) vs 1 (0-9) (p = 0.4) Mean number of good quality blastocysts- 2(0-19) vs 2 (0-17) (p = 0.68 ) Number of cycles with no blastocysts- 11.1 vs 16.1% (p = 0.35) Cumulative live birth rate 47 vs 48% (p = 0.99) SECONDARY OUTCOMES- Mean dose of gonadotropins- 3282+/- 913 iu vs 3119 vs 926iu (p = 0.07) Mean duration of stimulation- 11.67 +/- 1.87days vs 11.09 +/- 2days (p = 0.01) Mean number of oocytes retrieved-14.98+/- 7.14 vs 13.9+/-7.9 (p = 0.15) Mean number of mature oocytes-11.19+/- 5.64 vs 10.43+/-6.44 (p + 0.21) Mean fertilisation rate-10.7+/- 5.47 vs 9.81+/-6.08 (p = 0.12) Limitations, reasons for caution Retrospective design. Outcomes are assessed in frozen embryo transfer cycles, bur are not compared with fresh embryo transfer cycles. Wider implications of the findings The study provides reassuring data that low serum LH on the day of trigger does not affect the blastulation rates, quality of blastocysts and cumulative live birth rates in frozen embryo transfer cycles. Whether frozen embryo transfer can negate the effect of low pretrigger LH, further studies are needed. Trial registration number Not applicable