Artificial shrinkage before fresh blastocyst transfer and IVF outcomes: a pilot randomized controlled study.

RESEARCH QUESTION: Does artificial shrinkage before fresh blastocyst transfer improve clinical pregnancy rates in IVF? DESIGN: In this monocentric prospective, randomized, double-blind, controlled pilot study, 150 couples undergoing fresh single-blastocyst transfer were randomized between 20 May 2018 and 22 February 2022. In the artificial shrinkage group (AS group), a single laser pulse was directed to the cellular junction of the trophectoderm on the opposite side of the inner cell mass in each blastocyst. IVF outcomes were clinical pregnancy, multiple pregnancy and live birth rates. Cell-free DNA (cfDNA) concentration was also measured by quantitative real-time PCR in the blastocyst culture medium. RESULTS: In total, 142 couples underwent fresh single-blastocyst transfer: control group, no artificial shrinkage, n = 47; and AS group, artificial shrinkage, n = 95; An intention-to-treat (ITT) analysis was employed. After a reassessment and the exclusion of patients with major protocol deviations, 139 couples underwent fresh single-blastocyst transfer under optimal conditions: control group, n = 47; and AS group, n = 92; a per-protocol analysis was used here. The clinical and laboratory characteristics were not significantly different between the groups. The clinical pregnancy rate was similar in the control and AS groups (ITT: 48.9% versus 49.5%, P = 0.97; per protocol: 48.94% versus 51.1%, P = 0.89). The multiple pregnancy rate and the live birth rate were also similar between the groups. No significant differences in gestational age, birthweight or proportion of male/female newborns were observed. The concentration of cfDNA in the blastocyst culture medium was not associated with IVF outcome. CONCLUSIONS: Large-scale randomized controlled trials are required to confirm these preliminary results.

[The impact of oocyte cryopreservation time in oocyte donation on the clinical success rate]. / Impact de la durée de cryoconservation ovocytaire dans le cadre du don d'ovocytes sur le taux de succès clinique.

OBJECTIVES: To evaluate the impact of the cryopreservation time of vitrified oocytes on the success rates in oocyte donation cycles. METHODS: A retrospective study was carried out on 156 cycles with donated oocytes from January 2012 to September 2021. All the cycles were sorted according to the storage time of the oocytes (25 in the group 1:<3 months, 32 in the group 2: between 3 and 6 months, 39 in the group 3: between 6 and 12 months, 38 in the group 4: between 12 and 24 months and 22 in the group 5:>24 months). Clinical outcomes after ART, survival rates at thawing and oocyte fertilization rates were compared between the different cohorts stratified according to oocyte storage duration. A binary multivariate logistic regression was performed adjusting for the identified confounders. RESULTS: Prolonged storage time of vitrified oocytes had an effect on their survival post-thawing rates, but no significant effect was identified on fertilization rates or clinical outcomes. After adjusting for the confounders, the relationships between clinical outcomes and oocytes storage time did not reach statistical significance. Our study was characterized by a limited cohort with data from a single ART center. CONCLUSIONS: Our study doesn't highlight any significant difference in the use of long-stored vitrified oocytes (more than 2 years) on clinical issues in ART. The conclusion of our study needs to be verified in further studies with larger cohorts.

[Impact of SARS-CoV-2 on fertility, gametes' quality and Assisted Reproduction Technology]. / Impact du SARS-CoV-2 sur la fertilité, les gamètes et l'Assistance médicale à la procréation.

The current pandemic context raises questions about COVID-19 consequences on Assisted Reproduction Technology (ART). Indeed, according to the first Biomedicine Agency recommendations, ART centers suspended their activities in March 2020 during the first wave of Covid-19. However, SARS-CoV-2 direct and indirect effects on gametes, fertility, pregnancy and neonatal health are still debated. The aim of this review is to assess the available data on this subject, to inform patients in care and adapt daily practice. Most recent studies are based on the effects of the infectious syndrome, on hormonal factors as well as on the expression of viral entry proteins (ACE2 and TMPRSS2) in cells involved in gametogenesis, to assess the impact of COVID-19. So far, no effect on female gametes was highlighted. More studies are needed to confirm this hypothesis. Mother to children transmission couldn't be proven, yet neonatal infection remains possible. However, men are more susceptible to be infected by SARS-CoV-2, to be symptomatic, and spermatogenesis is likely to be affected. Presence of the virus in semen is infrequently reported, but all of these parameters should be taken into account in ART.

Biphasic (5-2%) oxygen concentration strategy significantly improves the usable blastocyst and cumulative live birth rates in in vitro fertilization.

Oxygen (O2) concentration is approximately 5% in the fallopian tube and 2% in the uterus in humans. A "back to nature" approach could increase in vitro fertilization (IVF) outcomes. This hypothesis was tested in this monocentric observational retrospective study that included 120 couples who underwent two IVF cycles between 2014 and 2019. Embryos were cultured at 5% from day 0 (D0) to D5/6 (monophasic O2 concentration strategy) in the first IVF cycle, and at 5% O2 from D0 to D3 and 2% O2 from D3 to D5/6 (biphasic O2 concentration strategy) in the second IVF cycle. The total and usable blastocyst rates (44.4% vs. 54.8%, p = 0.049 and 21.8% vs. 32.8%, p = 0.002, respectively) and the cumulative live birth rate (17.9% vs. 44.1%, p = 0.027) were significantly higher with the biphasic (5%-2%) O2 concentration strategy. Whole transcriptome analysis of blastocysts donated for research identified 707 RNAs that were differentially expressed in function of the O2 strategy (fold-change > 2, p value < 0.05). These genes are mainly involved in embryo development, DNA repair, embryonic stem cell pluripotency, and implantation potential. The biphasic (5-2%) O2 concentration strategy for preimplantation embryo culture could increase the "take home baby rate", thus improving IVF cost-effectiveness and infertility management.

Cryopreservation of Oocytes Retrieved from Ovarian Tissue to Optimize Fertility Preservation in Prepubertal Girls and Women.

Human ovarian tissue cryopreservation (OTC) is increasingly used worldwide to preserve female fertility in prepubertal girls and women at risk of premature ovarian insufficiency (POI) in the context of urgent gonadotoxic treatments or ovarian surgery. Fertility preservation is challenging because there is no consensus regarding patient management, preservation fertility strategies, or even technical laboratory protocols, which implies that each procedure must be adapted to the characteristics of the patient profile and its own risk-benefit ratio. During OTC, mature/immature oocytes can be aspirated directly from large/small antral follicles within ovarian tissue samples and/or be released into culture media from growing follicles during ovarian tissue dissection in prepubertal girls and women. In this manuscript, we present a protocol that combines ovarian tissue freezing with the cryopreservation of mature/immature oocytes retrieved from ovarian tissue samples, improving the reproductive potential of fertility preservation. Appropriate collection, handling, and storage of ovarian tissue and oocytes before, during, and after the cryopreservation will be described. The subsequent use and safety of cryopreserved/thawed ovarian tissue samples and oocytes will also be discussed, as well as the optimal timing for in vitro maturation of immature oocytes. We recommend the systematic use of this protocol in fertility preservation of prepubertal girls and women as it increases the whole reproductive potential of fertility preservation (i.e., oocyte vitrification in addition of OTC) and also improves the safety and use of fertility preservation (i.e., thawing of oocytes versus ovarian graft), maximizing the chance of successful childbirth for the patients at risk of POI.

Obesity does not adversely affect results in patients who are undergoing in vitro fertilization and embryo transfer.

OBJECTIVE: To examine the outcome of in vitro fertilization according to the body mass index of infertile patients. STUDY DESIGN: Between September 2003 and May 2005, 573 patients underwent 789 in vitro fertilization cycles or ICSI because of male factor, tubal factor, and unexplained infertility were retrospectively included from our IVF database. The patients were classified in four groups: BMI<20 kg/m2 (264 cycles), 20< or = BMI<25 (394 cycles), 25< or = BMI < 30 (83 cycles), and BMI> or = 30 (48 cycles). All patients had a long protocol for IVF with a combination of the GnRH agonist and recombinant FSH. RESULTS: All parameters of ovarian response were comparable except the total required r-FSH dose. This dose was statistically higher in the group of BMI> or = 30 compared to the other groups (p = 0.0003). All parameters of IVF outcome were comparable, including the cancellation rate, the implantation rate, and pregnancy rates. CONCLUSION: Obese patients require a higher r-FSH dose to achieve follicular maturation than normal weight patients. Obesity does not affect negatively results of in vitro fertilization.

Identifying new human oocyte marker genes: a microarray approach.

The efficacy of classical IVF techniques is still impaired by poor implantation and pregnancy rates after embryo transfer. This is mainly due to a lack of reliable criteria for the selection of embryos with sufficient development potential. Several studies have provided evidence that some gene expression levels could be used as objective markers of oocyte and embryo competence and capacity to sustain a successful pregnancy. These analyses usually use reverse transcription-polymerase chain reaction to look at small sets of pre-selected genes. However, microarray approaches allow the identification of a wider range of cellular marker genes which could include additional and perhaps more suitable genes that could serve as embryo selection markers. Microarray screenings of around 30,000 genes on U133P Affymetrix gene chips made it possible to establish the expression profile of these genes as well as other related genes in human oocytes and cumulus cells. This study identifies new potential regulators and marker genes such as BARD1, RBL2, RBBP7, BUB3 or BUB1B, which are involved in oocyte maturation.

Comparative protein expression profiling in human cumulus cells in relation to oocyte fertilization and ovarian stimulation protocol.

Comparative profiling was performed on proteins synthesized in human cumulus cells (CC) from individual oocytes recovered after two different ovarian stimulation protocols for classical IVF (cIVF). Using high-resolution two-dimensional protein electrophoresis after metabolic labelling with [35S]-methionine, protein expression was profiled in CC of metaphase II oocytes obtained after two different ovarian stimulation protocols (rFSH versus human menopausal gonadotrophin). Analysis was done on CC from two cIVF cycles in the same patient and then extended to CC from individual oocytes from two groups of patients. CC from single oocytes have robust levels of protein expression into 600-800 protein spots. Comparison of CC protein expression from oocytes obtained from the same patient but after two different stimulation protocols shows that the type of hormonal treatment influences CC protein expression. In contrast, CC from oocytes obtained under the same stimulation protocol but with different fertilization outcome show a high profile similarity with differences in only a few spots. Comparison of two groups of patients indicates that dissimilarities in protein pattern between patients become very high, even when comparing the same stimulation protocol and oocyte fertilization outcome. Thus protein expression profiling of human CC may provide a correlation between the synthesis of specific cumulus proteins and maturity and fecundity.