P–609 The chances of one live birth rates after first ART cycle in minimal stimulation cycle IVF with letrozole only and natural cycle IVF

Study question Are one live birth rates (LBRs) similar in minimal stimulation cycle IVF with letrozole only and natural cycle IVF for the first ART cycle? Summary answer LBRs after first ART cycle in minimal stimulation cycle IVF with letrozole only are superior to natural cycle IVF. What is known already The addition of letrozole to gonadotropins in ovarian stimulation (OS) may reduce the risk of OHSS, but there is no significant difference were reported in ongoing pregnancy rate or number of oocytes retrieved in the letrozole + FSH group compared to the FSH only. No differences were also reported in clinical pregnancy rates or number of mature oocytes in the additional of letrozole in an GnRH antagonist protocol group compared to the GnRH antagonist group. There are no previous study comparing LBRs after first ART cycle in minimal stimulation cycle IVF with letrozole and natural cycle IVF. Study design, size, duration Data for this retrospective cohort study were obtained 643 women, 30–39 years of age started their first ART cycle at one private fertility clinic between January 2016- December 2019. Participants/materials, setting, methods A total of 643 women were scheduled their first oocyte retrieval cycle. 118 women started with letrozole (LE) and 525 women started natural cycle (NC). The main strategy for OS in our center is minimal stimulation and natural cycle IVF. Patients consulted with gynecologists to determine their treatment plan based on patients’ preference or their menstrual cycle. All pregnancies generated from oocyte retrieval during the first IVF cycle including fresh and frozen-thaw cycles were registered. Main results and the role of chance The number of retrieved oocytes and the normal fertilization rates were significantly higher in the LE than NC (4.4 vs 3.4, 77.6% vs 71.1%), p < 0.05 respectively). There was no significant difference in the clinical pregnancy rates (CPRs) per embryo transfer (ET) (fresh cleavage stage ET: 32.9% vs 28.0%, frozen-thaw blastocyst ET: 39.4% vs 44.9% ns). However, the CPRs and LBRs per oocyte retrieval (OR) were significantly higher in the LE group (39.0% vs 28.6, 33.9% vs 21.9%, p < 0.05 respectively). In a subsequent regression analyses, LBRs per OR of LE was significantly higher than NC as well. (adjusted OR = 1.63 (95% CI: 1.02–2.58, p = 0.041). Limitations, reasons for caution The strength of the present study was the use of a large cohort of women who underwent minimal stimulation IVF with letrozole only. Although our results are promising, limited by retrospective cohort study. These interpretations prompted the need for a perspective cohort study to evaluate the efficacy of letrozole. Wider implications of the findings: When comparing minimal stimulation IVF with letrozole only and natural cycle IVF, we found significantly higher LBRs per OR in minimal stimulation IVF with letrozole only, despite similar CPRs per ET. Trial registration number none

Diclofenac Administered After the Initiation of Luteinizing Hormone Surge Increases Live Births in Natural-Cycle IVF-ET: A Cohort Study

Background: Diclofenac inhibits follicle rupture and its use in natural-cycle in vitro fertilization and embryo transfer (IVF-ET) has been reported to increase oocyte retrieval chances but has not been reported to improve the therapeutic outcome (live birth). The question is whether the therapeutic utility of diclofenac is demonstrable when administered to a subgroup of women with an imminent LH surge, a higher risk group for premature ovulation.Methods: Infertile women indicated for the natural-cycle IVF-ET between September 2014 and February 2015 (n=183) were recruited in a private infertility clinic and diclofenac use (50 mg suppositories, thrice every 8 h before oocyte retrieval) was offered when their serum LH level was ≥14.0 IU/L on an LH-triggering day (n=137). Of the 137 women, 108 electively used diclofenac and 29 did not. Oocytes were retrieved from both dominant and subordinate nondominant follicles and were fertilized. The resulting blastocysts were frozen, thawed, and transferred one by one in the following spontaneous ovulatory or hormone replacement cycles. Results: Cumulative live birth rate (after the single oocyte retrieval) was calculated from the dominant and nondominant follicles. The live birth rate from dominant follicles was higher in the diclofenac group (21/108, 19%) than in the no diclofenac group (1/29, 3%) (P < .05). Conversely, the live birth rate from nondominant follicles, which had no potential for ovulation, was not different between the diclofenac group (13/108, 12%) and the no diclofenac group (3/29, 10%). Conclusion: Diclofenac improved the live birth rate from dominant follicles when it was administered to women with an imminent LH surge. However, diclofenac did not affect the live birth rate from non-dominant follicles which were not at risk of follicle rupture.