Is a freeze-all policy the optimal solution to circumvent the effect of late follicular elevated progesterone? A multicentric matched-control retrospective study analysing cumulative live birth rate in 942 non-elective freeze-all cycles.

STUDY QUESTION: Is late follicular elevated progesterone (LFEP) in the fresh cycle hindering cumulative live birth rates (CLBRs) when a freeze only strategy is applied? SUMMARY ANSWER: LFEP in the fresh cycle does not affect the CLBR of the frozen transfers in a freeze only approach, nor the embryo freezing rate. WHAT IS KNOWN ALREADY: Ovarian stimulation promotes the production of progesterone (P) which has been demonstrated to have a deleterious effect on IVF outcomes. While there is robust evidence that this elevation produces impaired endometrial receptivity, the impact on embryo quality remains a matter of debate. In particular, previous studies have shown that LFEP is associated with a hindered CLBR. However, most clinical insight on the effect of progesterone on embryo quality in terms of CLBRs have focused on embryo transfers performed after the fresh transfer, thus excluding the first embryo of the cohort. To be really informative on the possible detrimental effects of LFEP, evidence should be derived from freeze-all cycles where no fresh embryo transfer is performed in the presence of progesterone elevation, and the entire cohort of embryos is cryopreserved. STUDY DESIGN, SIZE, DURATION: This was a matched case-control, multicentre (three centres), retrospective analysis including all GnRH antagonist ICSI cycles in which a freeze all (FA) policy of embryos on day 3/5/6 of embryonic development was applied between 2012 and 2018. A total of 942 patients (471 cases with elevated P and 471 matched controls with normal P values) were included in the analysis. Each patient was included only once. PARTICIPANTS/MATERIALS, SETTING, METHODS: The sample was divided according to the following P levels on the day of ovulation triggering: <1.50 ng/ml and ≥1.50 ng/ml. The matching of the controls was performed according to age (±1 year) and number of oocytes retrieved (±10%). The main outcome was CLBR defined as a live-born delivery after 24 weeks of gestation. MAIN RESULTS AND THE ROLE OF CHANCE: The baseline characteristics of the two groups were similar. Estradiol levels on the day of trigger were significantly higher in the elevated P group. There was no significant difference in terms of fertilisation rate between the two groups. The elevated P group had significantly more cleavage stage frozen embryos compared to the normal P group while the total number of cryopreserved blastocyst stage embryos was the same. The CLBR did not differ between the two study groups (29.3% and 28.2% in the normal versus LFEP respectively, P = 0.773), also following confounder adjustment using multivariable GEE regression analysis (accounting for age at oocyte retrieval, total dose of FSH, progesterone levels on the day of ovulation trigger, day of freezing, at least one top-quality embryo transferred and number of previous IVF cycles, as the independent variables). LIMITATIONS, REASONS FOR CAUTION: This is a multicentre observational study based on a retrospective data analysis. Better extrapolation of the results could be validated by performing a prospective analysis. WIDER IMPLICATIONS OF THE FINDINGS: This is the first study demonstrating that LFEP in the fresh cycle does not hinder CLBR of the subsequent frozen cycles in a FA approach. Thus, a FA strategy circumvents the issue of elevated P in the late follicular phase. STUDY FUNDING/COMPETING INTEREST(S): No funding was received for this study. Throughout the study period and manuscript preparation, authors were supported by departmental funds from: Centre for Reproductive Medicine, Brussels, Belgium; Infertility Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Centro Scienze Natalità, San Raffaele Scientific Institute, Milan, Italy; and IVI-RMA, Lisbon, Portugal. E.S. has competing interests with Ferring, Merck-Serono, Theramex and Gedeon-Richter outside the submitted work. E.P. reports grants from Ferring, grants and personal fees from Merck-Serono, grants and personal fees from MSD and grants from IBSA outside the submitted work. All the other authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: N/A.

Global transcriptomic changes occur in uterine fluid-derived extracellular vesicles during the endometrial window for embryo implantation.

STUDY QUESTION: Are uterine fluid-derived extracellular vesicles (UF-EVs) a 'liquid biopsy' reservoir of biomarkers for real-time monitoring of endometrial status? SUMMARY ANSWER: The transcriptomic cargo of UF-EVs reflects the RNA profile of the endometrial tissue as well as changes between the non-receptive and the receptive phase, possibly supporting its use for a novel endometrial receptivity test. WHAT IS KNOWN ALREADY: EVs have been previously isolated from uterine fluid, where they likely contribute to the embryo-endometrium crosstalk during implantation. Based on a meta-analysis of studies on endometrial tissue implantation-associated genes and the human exosomes database, 28 of the 57 transcripts considered as receptivity markers refer to proteins present in human exosomes. However, the specific transcriptomic content of receptive phase UF-EVs has yet to be defined. STUDY DESIGN, SIZE, DURATION: Two experimental series were set up. First, we simultaneously sequenced RNA species derived from paired UF-EVs and endometrial tissue samples collected from physiologically cycling women. Second, we analyzed RNA species of UF-EVs collected during the non-receptive (LH + 2) and receptive (LH + 7) phase of proven fertile women and from the receptive (LH + 7) phase of a population of women undergoing ART and transfer of euploid blastocysts. PARTICIPANTS/MATERIALS, SETTING, METHODS: For paired UF-endometrial tissue sampling, endometrial tissue biopsies were obtained with the use of a Pipelle immediately after UF collection performed by lavage of the endometrial cavity. Overall, n = 87 UF samples were collected and fresh-processed for EV isolation and total RNA extraction, while western blotting was used to confirm the expression of EV protein markers of the isolated vesicles. Physical characterization of UF-EVs was performed by Nanoparticle Tracking Analysis. To define the transcriptomic cargo of UF-EV samples, RNA-seq libraries were successfully prepared from n = 83 UF-EVs samples and analyzed by RNA-seq analysis. Differential gene expression (DGE) analysis was used to compare RNA-seq results between different groups of samples. Functional enrichment analysis was performed by gene set enrichment analysis with g:Profiler. Pre-ranked gene set enrichment analysis (GSEA) with WebGestalt was used to compare RNA-seq results with the gene-set evaluated in a commercially available endometrial receptivity array. MAIN RESULTS AND THE ROLE OF CHANCE: A highly significant correlation was found between transcriptional profiles of endometrial biopsies and pairwise UF-EV samples (Pearson's r = 0.70 P < 0.0001; Spearman's ρ = 0.65 P < 0.0001). In UF-EVs from fertile controls, 942 gene transcripts were more abundant and 1305 transcripts less abundant in the LH + 7 receptive versus the LH + 2 non-receptive phase. GSEA performed to evaluate concordance in transcriptional profile between the n = 238 genes included in the commercially available endometrial receptivity array and the LH + 7 versus LH + 2 UF-EV comparison demonstrated an extremely significant and consistent enrichment, with a normalized enrichment score (NES)=9.38 (P < 0.001) for transcripts up-regulated in LH + 7 in the commercial array and enriched in LH + 7 UF-EVs, and a NES = -5.40 (P < 0.001) for transcripts down-regulated in LH + 7 in the commercial array and depleted in LH + 7 UF-EVs. When analyzing LH + 7 UF-EVs of patients with successful versus failed implantation after transfer of one euploid blastocyst in the following cycle, we found 97 genes whose transcript levels were increased and 64 genes whose transcript levels were decreased in the group of women who achieved a pregnancy. GSEA performed to evaluate concordance in transcriptional profile between the commercially available endometrial receptivity array genes and the comparison of LH + 7 UF-EVs of women with successful versus failed implantation, demonstrated a significant enrichment with a NES = 2.14 (P = 0.001) for transcripts up-regulated in the commercial array in the receptive phase and enriched in UF-EVs of women who conceived, and a not significant NES = -1.18 (P = 0.3) for transcripts down-regulated in the commercial array and depleted in UF-EVs. In terms of physical features, UF-EVs showed a homogeneity among the different groups analyzed except for a slight but significant difference in EV size, being smaller in women with a successful implantation compared to patients who failed to conceive after euploid blastocyst transfer (mean diameter ± SD 205.5± 22.97 nm vs 221.5 ± 20.57 nm, respectively, P = 0.014). LARGE SCALE DATA: Transcriptomic data were deposited in NCBI Gene Expression Omnibus (GEO) and can be retrieved using GEO series accession number: GSE158958. LIMITATIONS, REASONS FOR CAUTION: Separation of RNA species associated with EV membranes might have been incomplete, and membrane-bound RNA species-rather than the internal RNA content of EVs-might have contributed to our RNA-seq results. Also, we cannot definitely distinguish the relative contribution of exosomes, microvesicles and apoptotic bodies to our findings. When considering patients undergoing ART, we did not collect UFs in the same cycle of the euploid embryo transfer but in the one immediately preceding. We considered this approach as the most appropriate in relation to the novel, explorative nature of our study. Based on our results, a validation of UF-EV RNA-seq analyses in the same cycle in which embryo transfer is performed could be hypothesized. WIDER IMPLICATIONS OF THE FINDINGS: On the largest sample size of human EVs ever analyzed with RNA-seq, this study establishes a gene signature to use for less-invasive endometrial receptivity tests. This report is indeed the first to show that the transcriptome of UF-EVs correlates with the endometrial tissue transcriptome, that RNA signatures in UF-EVs change with endometrial status, and that UF-EVs could serve as a reservoir for potential less-invasive collection of receptivity markers. This article thus represents a step forward in the design of less-invasive approaches for real-time monitoring of endometrial status, necessary for advancing the field of reproductive medicine. STUDY FUNDING/COMPETING INTEREST(S): The study was funded by a competitive grant from European Society of Human Reproduction and Embryology (ESHRE Research Grant 2016-1). The authors have no financial or non-financial competing interests to disclose. TRIAL REGISTRATION NUMBER: NA.

Do we trust scientific evidence? A multicentre retrospective analysis of first IVF/ICSI cycles before and after the OPTIMIST trial.

STUDY QUESTION: Has the practice of individualizing the recombinant-FSH starting dose been superseded after the largest randomized controlled trial (RCT) in assisted reproduction technology (ART), the OPTIMIST trial? SUMMARY ANSWER: The OPTIMIST trial has influenced our ART daily practice to a limited degree, but adherence is still generally poor. WHAT IS KNOWN ALREADY: Although the 'one size fits all' approach has been discouraged for decades by most authors, the OPTIMIST study group demonstrated in a large prospective RCT that, in general, dosage individualization does not improve the prospects for live birth, although it may decrease ovarian hyperstimulation syndrome (OHSS) risk in expected high responders. STUDY DESIGN, SIZE, DURATION: Retrospective analysis of all first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles from 1st January 2017 to 31st December 2018, before and after the OPTIMIST publication on November 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two thousand six hundred and seventy-seven patients, between 18 and 42 years old, undergoing their first IVF-ICSI cycle in seven Italian fertility centres, were included. Patients were allocated to three groups according to their ovarian reserve markers: predicted poor ovarian responders (POR), predicted normo-responders (NR) and expected hyper-responders (HRs). MAIN RESULTS AND THE ROLE OF CHANCE: Between 2017 and 2018, there was an overall increase in prescription of the standard 150 IU dose proposed by the OPTIMIST trial and a reduction in the use of a starting dose >300 IU. After subgroup analysis, the decrease in doses >300 IU remained significant in the POR and NR sub-groups. LIMITATIONS, REASONS FOR CAUTION: The retrospective nature of the study. Physicians need time to adapt to new scientific evidence and a comparison between 2017 and 2019 may have found a greater impact of the Optimist trial, although other changes over the longer time span might have increased confounding. We cannot be sure that the observed changes can be attributed to knowledge of the OPTIMIST trial. WIDER IMPLICATIONS OF THE FINDINGS: Clinicians may be slow to adopt recommendations based on RCTs; more attention should be given to how these are disseminated and promoted. STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for this study. E.P. reports grants and personal fees from MSD, grants from Ferring, from IBSA, grants and personal fees from Merck, grants from TEVA, grants from Gedeon Richter, outside the submitted work. E.S. reports grants from Ferring, grants and personal fees from Merck-Serono, grants and personal fees from Theramex, outside the submitted work. All other authors do not have conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.

Prospective longitudinal cohort study of uterine arteries Doppler in singleton pregnancies obtained by IVF/ICSI with oocyte donation or natural conception.

STUDY QUESTION: Do uterine arteries Doppler studies show different pulsatility index (UtA-PI) measurements in IVF/ICSI pregnancies with oocyte donation (OD) as compared to natural conceptions? SUMMARY ANSWER: In IVF/ICSI pregnancies with OD, UtA-PI is reduced by an average of about 40% as compared to pregnancies with natural conception. WHAT IS KNOWN ALREADY: OD pregnancies present worse pregnancy outcomes as compared to natural conception, particularly for increased incidence of pre-eclampsia (PE). Recent evidence shows that IVF/ICSI pregnancies with frozen blastocyst transfer also present higher prevalence of PE and 15% lower UtA-PI as compared to pregnancies after fresh blastocyst transfers. STUDY DESIGN, SIZE, DURATION: Prospective, longitudinal matched cohort study performed in the Fetal Medicine and Obstetric Departments of San Raffaele Hospital in Milan, between 2013 and 2018. The analysis is based on 584 Doppler observations collected from 296 women with different method of conception (OD n = 122; natural conception n = 174). PARTICIPANTS/MATERIALS, SETTING, METHODS: IVF/ICSI viable singleton pregnancies with OD and natural conception control pregnancies matched for BMI and smoking, performing repeated UtA-PI measurements at 11-34 weeks. Miscarriages, abnormalities, twins, significant maternal diseases and other types of ARTs were excluded. Log mean left-right UtA-PI was used for analysis with linear mixed model (LMM) and correction for significant confounders. Pregnancy outcome was also analyzed. MAIN RESULTS AND THE ROLE OF CHANCE: Participants after OD were older and more frequently nulliparous (mean age: OD 43.4, 95% CI from 42.3 to 44.6; natural conception 35.1, 95% CI from 34.5 to 35.7; P-value < 0.001; nulliparous: OD 96.6%; natural conception 56.2%; P-value < 0.001). Mean pulsatility index was lower in OD (UtA-PI: natural conception 1.22; 95% CI from 1.11 to 1.28; OD 1.04; 95% CI from 0.96 to 1.12; P-value < 0.001). A significant effect of parity, gestational age (GA) modeled with a cubic polynomial and BMI was described in the LMM. The mean Log UtA-PI was on average 37% lower in OD as compared to natural conception pregnancies at LMM (P-value < 0.001). We also found a significant interaction between longitudinal UtA-PI Doppler and GA. Therefore, at 11 weeks' gestation the Log UtA-PI was 42% lower and, at 34 weeks, the differences reduced to 32%. GA at delivery and birth weight were statistically lower in OD group; however, birthweight centile was not statistically different. Preeclampsia was 11-fold more common in the OD group (0.6% and 6.6%, P-value = 0.003). No other significant difference in pregnancy outcome was shown in the study groups (gestational diabetes mellitus, small or large for GA). LIMITATIONS, REASONS FOR CAUTION: It was not possible to properly match for maternal age and to blind the assessment given the major differences between cohorts; however, we did not find significant within-groups effects related to maternal age. Future research is needed to reassess outcomes and correct them for maternal characteristics (e.g. cardiovascular function). WIDER IMPLICATIONS OF THE FINDINGS: This finding reproduces our previous discovery of lower UtA-PI in frozen as compared to fresh blastocyst transfer. The vast majority of OD is obtained by the use of cryopreservation. We speculate that increased uterine perfusion may be the physiological response to compensate dysfunctions both in the mother and in the placenta. STUDY FUNDING/COMPETING INTEREST(S): This is a non-funded study. The authors do not declare competing interest. TRIAL REGISTRATION NUMBER: N/A.

Safety of fertility treatments in women with systemic autoimmune diseases (SADs).

Introduction: Systemic Autoimmune Diseases (SADs) include systemic lupus erythematosus, antiphospholipid antibody syndrome, rheumatoid arthritis, systemic sclerosis, Sjogren's syndrome, mixed connective tissue disease, idiopathic inflammatory myopathies and vasculitis. SADs often occur in women of childbearing age and can affect fertility. Both infertility treatments and fertility preservation techniques are thus often indicated. Areas covered: The literature regarding the safety of fertility-related drugs for both fertility preservation and infertility treatment in patients affected by SADs was reviewed. Based on current knowledge, all the options for fertility preservation should be contemplated in patients with SADs who are at risk for fertility loss, including GnRH analogue administration, oocyte/embryo vitrification and ovarian tissue cryopreservation. Similarly, if pregnancy is not contraindicated in a patient with a SAD, neither should be any fertility treatment. Expert opinion: Women with SADs should postpone conception until a stable disease has been achieved for at least 6 months. When infertility treatments are needed, women with antiphospholipid antibodies should receive concomitant anticoagulation. If in vitro fertilization/intra-cytoplasmic sperm injection and embryo transfer is required, ovarian hyperstimulation and the inherent risk of thrombosis should be eliminated by GnRH-agonist trigger and cycle segmentation. Counselling about adherence to anti-rheumatic therapy to prevent disease exacerbations is also critical.

Embryonic extracellular vesicles as informers to the immune cells at the maternal-fetal interface.

Extracellular vesicle (EV) exchange is emerging as a novel method of communication at the maternal-fetal interface. The presence of the EVs has been demonstrated in the preimplantation embryo culture medium from different species, such as bovines, porcines and humans. Preimplantation embryo-derived EVs have been shown to carry molecules potentially able to modulate the local endometrial immune system. The non-classical major histocompatibility complex (MHC) class I molecule human leucocyte antigen (HLA)-G, the immunomodulatory molecule progesterone-induced blocking factor and some regulatory miRNAs species are contained in embryo-derived EV cargo. The implanted syncytiotrophoblasts are also well known to secrete EVs, with microvesicles exerting a mainly proinflammatory effect while exosomes in general mediate local immunotolerance. This review focuses on the current knowledge on the potential role of EVs released by the embryo in the first weeks of pregnancy on the maternal immune cells. Collectively, the data warrant further exploration of the dialogue between the mother and the embryo via EVs.

Top quality blastocyst formation rates in relation to progesterone levels on the day of oocyte maturation in GnRH antagonist IVF/ICSI cycles.

Cycles with progesterone elevation during controlled ovarian stimulation (COS) for IVF/ICSI are commonly managed with a "freeze-all" strategy, due to a well-recognized detrimental effect of high progesterone levels on endometrial receptivity. However, also a detrimental effect of elevated progesterone on day-3 embryo quality has recently been found with regards to top quality embryo formation rate. Because blastocyst culture and cryopreservation are largely adopted, we deemed relevant to determine whether this detrimental effect is also seen on blastocyst quality on day 5-6. This issue was investigated through a large two-center retrospective study including 986 GnRH antagonist IVF/ICSI cycles and using top quality blastocyst formation rate as the main outcome. Results showed that on multivariate analysis sperm motility (p<0.01) and progesterone levels at ovulation triggering (p = 0.01) were the only two variables that significantly predicted top quality blastocyst formation rate after adjusting for relevant factors including female age, BMI, basal AMH and total dose of FSH used for COS. More specifically, progesterone levels at induction showed an inverse relation with top quality blastocyst formation (correlation coefficient B = -1.08, 95% CI -1.9 to -0.02) and ROC curve analysis identified P level >1.49 ng/ml as the best cut-off for identification of patients at risk for the absence of top quality blastocysts (AUC 0.55, p<0.01). Our study is the first to investigate the top quality blastocyst formation rate in relation to progesterone levels in IVF/ICSI cycles, showing that increasing progesterone is associated with lower rates of top quality blastocyst. Hence, the advantages of prolonging COS to maximize the number of collected oocytes might eventually be hindered by a decrease in top quality blastocysts available for transfer, if increasing progesterone levels are observed. This observation extends the results of two recent studies focused on day-3 embryos and deserves further research.

Are extremely high progesterone levels still an issue in IVF?

BACKGROUND: Premature luteinization of one or more developing follicles complicates 1-2 % of controlled ovarian stimulation cycles for assisted reproduction. The management of this complication is controversial, with cycle cancellation likely representing the most commonly used strategy. The aim of this study was to evaluate the efficacy of the "freeze-all" policy-where the entire cohort of blastocysts is cryopreserved for subsequent frozen-thawed embryo transfer-in treating cases of premature luteinization. METHODS: Patients experiencing premature luteinization during controlled ovarian stimulation-identified by extremely high progesterone levels at induction (P levels ≥3.0 ng/ml and/or P/estradiol ratio ≥1, n = 42)-were included in a "freeze-all" program and compared to controls undergoing a "freeze-all" program with normal progesterone levels at induction (P < 1.5 ng/ml, n = 67). RESULTS: Blastulation rate was comparable between patients with premature luteinization and controls (48.1 ± 20.5 % in Cases vs. 52.3 ± 24.9 % in Controls, p = 0.36). Ongoing pregnancy rates after the first frozen-thawed embryo transfer (38.1 % in Cases and 41.0 % in Controls, p = 0.83) and cumulative ongoing pregnancy rates after three frozen-thawed embryo transfer cycles (40.5 % in Cases vs. 47.8 % in Controls, p = 0.55) were also similar. CONCLUSIONS: These results show that extremely marked progesterone elevation throughout controlled ovarian stimulation does not impair blastocyst development and implantation potential in the context of a "freeze-all" strategy. Based on this, adoption of the "freeze-all" strategy represents a valuable tool in treating premature luteinization. In contrast, cycle cancellation-likely the most frequently used method for management of this complication-currently represents a misconduct.