P–607 luteal phase stimulation results in similar euploid blastocysts rate vs. conventional stimulation: donor-recipient cycles
Authors: Martazanova B , Lapina V , Mishieva N , Kirillova A , Abubakirov A 
Published: August 2021

Abstract

Study question
Does the luteal phase stimulation (LPS) impact the embryological outcomes, euploid blastocyst rate, and pregnancy rate compared to conventional stimulation in donor-recipient cycles?

Summary answer
LPS is associated with similar embryological outcomes, euploid blastocyst rate, and pregnancy rate among the corresponding recipients compared to stimulation in the follicular phase.

What is known already
LPS has been suggested for fertility preservation in cancer patients, but now it is a part of the new double-stimulation strategy applied to poor responders. Some studies found no difference in the number of oocytes retrieved with LPS compared to conventional stimulation. According to other data, LPS increased numbers of retrieved oocytes compared to follicular stimulation (FPS). Previous studies showed a similar euploid blastocyst formation rate after LPS using the DuoStim approach in poor prognosis patients. However, there is limited data about the embryological outcomes and IVF treatment success in patients with normal ovarian reserve undergoing the LPS.

Study design, size, duration
This prospective observational study included 25 oocyte donors. Group 1 (n = 12) received stimulation on day 2 follicular phase. In group 2 (n = 13) received the stimulation on 2–4 day after the ovulation. The definition of spontaneous ovulation included the presence of collapsed follicle/corpus luteum in an ultrasound examination, an increase in the serum P level ≥ 2.0 ng/mL. The blastocyst biopsy and aneuploidy screening were performed for 63 embryos.

Participants/materials, setting, methods
Inclusion criteria: age 18–35 years; basal FSH&lt;10 IU/ml; regular cycle; spontaneous ovulation; AFC&gt;10; normal karyotype; physically and mentally healthy. Exclusion criteria: uterine fibroids; deep endometriosis; PCOS; reduce ovarian reserve. Blastocysts were graded using the Gardner and Schoolcraft classification. Trophectoderm biopsy was performed using the Octax lazer (Sweden). Detection of aneuploidies was performed using the ReproSeq PGS Kit according to the manufactures instruction. Aneuploidy haplotyping was done using Applied Biosystems (4-capillary) Genetic Analyzer.

Main results and the role of chance
No statistically significant differences were found in the number of mature oocytes (20.1±5.58 vs. 21.00±6.1,p=1.0), in the number of donated oocytes (6.17±2.3 vs. 5.7±2.01,p=0.57), in an average number of the blastocyst (4.58 ± 2.2 vs. 3.84 ± 1.8, P = 0.43), in an average number of the euploid blastocyst (1.9 ±1.3 vs. 1.7 ± 1.2, P = 0.78) from FPS versus LPS stimulation, respectively. The euploid blastocyst rate calculated per donated oocytes (30.4% vs. 31.8%,p=1.0), the euploid blastocyst rate calculated per two-pronuclear zygote (31.8% vs. 38%,p=0.56), the euploid blastocyst rate calculated per biopsied blastocyst (63.6% vs. 70%, p = 0.78) also were similar after FPS and LPS stimulation. There were no differences between the groups of recipients in fertilization rate (95.7% vs. 83%, p = 0.13). Only one embryo was transferred in artificial frozen-thawed embryo transfer to corresponding recipients. The pregnancy rate per embryo transfer was comparable in both groups ((64% (7/11), 95%CI: 30.8–89.0 vs. 62.5% (5/8), 95%CI: 24.5–91.5, p = 1.0, in group I and II, respectively).

Limitations, reasons for caution
Our study was carried out in a relatively small subset of patients; therefore, obtained results cannot be extrapolated on other groups of patients and need to be confirmed in larger trials.
Wider implications of the findings: This study opens new possibilities for investigating the luteal. phase stimulation impact on oocyte competence and embryo development

Trial registration number
approved by the ethics committee and Institutional Review Board at 07.09.2017 protocol №10 of Kulakov National Medical Research Centre of Obstetrics, Gynecology and Perinatology. All participants provided written consent.