Evaluation of Early Frozen Blastocyst Transfer in A True Natural Cycle Protocol in Comparison to A Hormone Replacement Protocol: A Single-Center Cohort Study.

OBJECTIVE: Timing of frozen embryo transfer (FET) within a purported window of implantation is of increasing interest, and there is a paucity of evidence surrounding the transfer of frozen embryos early within these frozen embryo transfer protocols. This study aimed to evaluate whether live birth rates were equivalent after FET of blastocysts 4 days after luteinizing hormone (LH) surge in a true natural cycle protocol, compared to a hormone replacement (HR) protocol. MATERIALS AND METHODS: Single-centre, retrospective cohort study involving patients undergoing autologous frozen blastocyst transfer from January 1st, 2013, to December 31st, 2016. Cycles were grouped according to their protocol: true natural cycle (hormonal detection of LH surge with FET scheduled four days later) versus HR cycle (luteal phase gonadotropin-releasing hormone agonist suppression, oral or vaginal estradiol and intramuscular progesterone starting five days before FET). A total of 850 cycles were included, 501 true natural cycles and 349 HR cycles. The primary outcome was the live birth rate, secondary outcomes included clinical pregnancy rate and miscarriage. Logbinomial regression models were performed adjusting for a priori selected variables. RESULTS: Adjusted resulted in live birth rates of 38.7 and 40.4%, [adjusted risk ratio (aRR): 0.96, 95% confidence interval (CI): 0.76-1.22, P=0.729] in the natural cycle and HR groups, respectively. The secondary outcome analyses did not demonstrate any statistically significant difference in the rate of positive human chorionic gonadotropin (hCG), clinical intrauterine pregnancy rate, or miscarriage rate. CONCLUSION: The timing of the FET four days after LH surge in a true natural cycle protocol results in equivalent live birth rates compared to a HR protocol. Results of this study suggest that the window of implantation within the natural cycle may be less finite than currently believed and further prospective studies evaluating the timing of frozen embryo transfer are warranted.

Comparative Embryo Development Outcomes following Extending Embryo Culture to Day 6: A Retrospective Cohort Study.

BACKGROUND: Past studies have shown that culturing slow-growing embryos from day 5 to day 6 may increase vitrification yield. This study aims to evaluate if the proportion of embryos eligible for vitrification increases by growing embryos not vitrified by day 5 to day 6. MATERIALS AND METHODS: In this retrospective cohort study, a Canadian tertiary-care clinic-based cohort was identified between August 2019 and December 2020. In vitro fertilization (IVF) cycles involving autologous oocytes with at least one viable day 5 embryo were selected for inclusion. We compared embryo developmental outcomes of IVF cycles performed before and after an embryo cryopreservation policy change. Prior to March 2020, good-quality day 5 blastocysts of any stage were eligible for vitrification, and after that date, good-quality expanded blastocysts on either day 5 or day 6 were eligible. The primary outcome is the comparative proportion of embryos eligible for vitrification. The secondary outcome is to identify embryo, maternal and cycle factors that are predictive of day 6 vitrification. RESULTS: A total of 3,438 viable embryos across 679 consecutive IVF cycles were included in this study. After the policy change, we found similar mean proportions of blastocysts eligible for cryopreservation (46.9% per IVF cycle in group 2 vs. 44.4% in group 1, mean difference 0.025, 95% confidence interval -0.021 to 0.071, P=0.28). The mean number of cryopreserved embryos were significantly higher in group 2 (mean 2.2 vs. 1.7 embryos, P=0.007). Factors that predicated an embryo's progression to day 6 included: younger age of egg provider, presence of an early blastocyst on day 5, and cycles involving surgically-retrieved sperm. CONCLUSION: A cryopreservation policy change to include good-quality full and expanded day 6 blastocysts while avoiding to vitrify early blastocysts on day 5 yielded comparable proportions of embryos eligible for vitrification per IVF cycle.

Time-lapse KIDScoreD5 for prediction of embryo pregnancy potential in fresh and vitrified-warmed single-embryo transfers.

RESEARCH QUESTION: Can KIDScoreD5 predict which blastocysts have the highest potential for achieving pregnancy? DESIGN: A retrospective cohort study of 670 single fresh or frozen (FET) embryo transfer cycles was conducted between May 2019 and June 2021 at the Ottawa Fertility Centre, Canada. Blastocysts obtained from stimulated eligible cycles and cultured in a time-lapse incubator were selected for transfer or cryopreservation based on Gardner morphological scoring. Implantation and viable pregnancy rates were analysed retrospectively using KIDScoreD5 and Gardner scores associated with the transferred embryos. The predictive power of the KIDScoreD5 and Gardner assessment was evaluated using the average area under the curve (AUC) of the receiver operating characteristic curve. RESULTS: KIDScoreD5 was positively correlated with implantation (r = 0.96, P = 0.002) and viable pregnancy (r = 0.96, P  = 0.0001) rates. In fresh embryo transfer cycles, the AUC for implantation rate was significantly higher for KIDScoreD5 compared with Gardner scoring (0.70 versus 0.63, P  = 0.03). For FET, significantly higher AUC were calculated for KIDScoreD5 than for Gardner scoring, for both implantation (0.64 versus 0.54, P  = 0.002) and viable pregnancy (0.63 versus 0.53, P  = 0.002) rates. When the ranking of cryopreserved embryos was based on KIDScoreD5, 46.2% of the FET cycles had at least one unused sibling embryo with a better KIDScoreD5 than the one selected for FET based on Gardner assessment. CONCLUSIONS: KIDScoreD5 predicts implantation and viable pregnancy rates of blastocysts better than Gardner morphological assessment in single fresh or cryopreserved embryo transfer cycles.

Patients who failed to conceive following an in vitro fertilization cycle can be clustered into different failure causes using gene expression hierarchical analysis†.

The patient's response to an IVF stimulation protocol is highly variable and thus difficult to predict. When a cycle fails, there are often no apparent or obvious reasons to explain the failure. Having clues on what went wrong during stimulation could serve as a basis to improve and personalize the next protocol. This exploratory study aimed to investigate if it is possible to distinguish different failure causes or different follicular responses in a population of nonpregnant IVF patients. Using qRT-PCR, we analyzed a panel of genes indicative of different failure causes in patients who did not achieve pregnancy following an IVF cycle. For each patient, a pool of follicular cells from all aspirated follicles was used as a sample which gives a global picture of the patient's ovary and not a specific picture of each follicle. We performed hierarchical clustering analysis to split the patients according to the gene expression pattern. Hierarchical analysis showed that the population of nonpregnant IVF patients could be divided into three clusters. Gene expression was significantly different, and each cluster displayed a particular gene expression pattern. Follicular cells from patients in clusters 1, 2 and 3 displayed respectively a pattern of gene expression related to large incompetent follicles with a higher apoptosis (over matured), to follicles not ready to ovulate (under mature) and to an excess of inflammation with no visible symptoms. This study reinforces the idea that women often have different response to the same protocol and would benefit from more personalized treatments.

Does omitting teratospermia as a selection criterion for ICSI change pregnancy rates?

PURPOSE: There is controversy whether teratospermia is associated with poorer IVF outcomes and if ICSI may overcome this deficit. The debate likely lies in study heterogeneity, poor adjustment for confounders, and inter-observer variation in sperm morphology assessment. Given the current literature, a shift in practice was implemented at our center in February 2017, whereby teratospermia was no longer a criterion for ICSI. We hypothesized that, despite decreasing ICSI rates, we would see no change in ART outcomes. METHODS: A retrospective study was performed including 1821 couples undergoing IVF/ICSI at a single center from January 2016 to December 2018, divided into cohorts before and after the practice change. The primary outcome of clinical pregnancy and secondary outcomes of fertilization, fertilization failure, good quality blastocyst formation, embryo utilization, positive hCG, and miscarriage rates was compared, adjusting for potential confounders. Subgroup analysis was performed evaluating teratospermia as the only reason for a male factor infertility diagnosis. RESULTS: Despite a decrease in ICSI rate of 30.3%, we found no significant difference in clinical intrauterine pregnancy rate, with an adjusted relative risk of 0.93 (0.81, 1.07, P = 0.3008). There were no significant differences in other secondary outcomes after multivariate adjustment. Subgroup analysis for those with male factor infertility due to teratospermia showed no difference in outcomes. CONCLUSION: This study concurs with the recent data suggesting that employing ICSI solely for teratospermia is unnecessary. This may allow clinics to decrease ICSI rates without sacrificing success rates, leading to lower cost and risk associated with treatment.

Human sperm vitrification: the state of the art.

Sperm cryopreservation has been widely used in assisted reproductive technology (ART) and has resulted in millions of live births. Two principal approaches have been adopted: conventional (slow) freezing and vitrification. As a traditional technique, slow freezing has been successfully employed and widely used at ART clinics whereas the latter, a process to solidify liquid into an amorphous or glassy state, may become a faster alternative method of sperm cryopreservation with significant benefits in regard to simple equipment and applicability to fertility centers. Sperm vitrification has its own limitations. Firstly, small volume of load is usually plunged to liquid nitrogen to achieve high cooling rate, which makes large volume sample cryopreservation less feasible. Secondly, direct contact with liquid nitrogen increases the potential risk of contamination. Recently, new carriers have been developed to facilitate improved control over the volume and speed, and new strategies have been implemented to minimize the contamination risk. In summary, although sperm vitrification has not yet been applied in routine sperm cryopreservation, its potential as a standard procedure is growing.

Gene expression analysis of follicular cells revealed inflammation as a potential IVF failure cause.

PURPOSE: Hormonal stimulation prior to IVF influences the ovarian environment and therefore impacts oocytes and subsequent embryo quality. Not every patient has the same response to the same treatment and many fail for unknown reasons. Knowing why a cycle has failed and how the follicles were affected would allow clinicians to adapt the treatment accordingly and improve success rate. This study examines the hypothesis that transcriptomic analysis of follicular cells from failed IVF cycles reveals potential reasons for failure and provides new information on the physiological mechanisms related to IVF failure. METHODS: Follicular cells (granulosa cells) were obtained from IVF patients of four Canadian fertility clinics. Using microarray analysis, patients that did not become pregnant following the IVF cycle were compared to those that did. Functional analysis was performed using ingenuity pathway analysis and qRT-PCR was used to validate the microarray results in a larger cohort of patients. RESULTS: The microarray showed 165 differentially expressed genes (DEGs) in the negative group compared to the pregnancy group. DEGs include many pro-inflammatory cytokines and other factors related to inflammation, suggesting that this process might be altered when IVF fails. Overexpression of several factors, some of which act upstream from vascular endothelial growth factor (VEGF), also indicates increased permeability and vasodilation. Some DEGs were related to abnormal differentiation and increased apoptosis. CONCLUSIONS: Our results suggest that failure to conceive following IVF cycles could be associated with an imbalance between pro-inflammatory and anti-inflammatory mediators. The findings of this study identify potential failure causes and pathways for further investigation. Stimulatory protocols personalized according to patient response could improve the chances of later success.

Can peri-ovulatory putrescine supplementation improve egg quality in older infertile women?

The aging-related decline in fertility is an increasingly pressing medical and economic issue in modern society where women are delaying family building. Increasingly sophisticated, costly, and often increasingly invasive, assisted reproductive clinical protocols and laboratory technologies (ART) have helped many older women achieve their reproductive goals. Current ART procedures have not been able to address the fundamental problem of oocyte aging, the increased rate of egg aneuploidy, and the decline of developmental potential of the eggs. Oocyte maturation, which is triggered by luteinizing hormone (LH) in vivo or by injection of human chorionic gonadotropin (hCG) in an in vitro fertilization (IVF) clinic, is the critical stage at which the majority of egg aneuploidies arise and when much of an egg's developmental potential is established. Our proposed strategy focuses on improving egg quality in older women by restoring a robust oocyte maturation process. We have identified putrescine deficiency as one of the causes of poor egg quality in an aged mouse model. Putrescine is a biogenic polyamine naturally produced in peri-ovulatory ovaries. Peri-ovulatory putrescine supplementation has reduced egg aneuploidy, improved embryo quality, and reduced miscarriage rates in aged mice. In this paper, we review the literature on putrescine, its occurrence and physiology in living organisms, and its unique role in oocyte maturation. Preliminary human data demonstrates that there is a maternal aging-related deficiency in ovarian ornithine decarboxylase (ODC), the enzyme responsible for putrescine production. We argue that peri-ovulatory putrescine supplementation holds great promise as a natural and effective therapy for infertility in women of advanced maternal age, applicable in natural conception and in combination with current ART therapies.

Does ovarian reserve predict egg quality in unstimulated therapeutic donor insemination cycles?

OBJECTIVE: To compare reproductive outcomes of patients with very low, low, normal, and high antral follicle counts undergoing unstimulated therapeutic donor insemination (TDI) cycles. DESIGN: Retrospective cohort study. SETTING: University-affiliated regional fertility clinic. PATIENT(S): Four hundred fifty-nine patients who had 1,107 TDI treatment cycles from January 2006 to December 2013. INTERVENTION(S): Unstimulated therapeutic donor insemination. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates and miscarriage rates as surrogate markers for oocyte quality. RESULT(S): The overall pregnancy rate per cycle start was 12.46% in the study population. There was no difference in per-cycle or cumulative pregnancy rates among patients with very low, low, average, or high antral follicle counts within each patient age group of ≤35, 36-39, and ≥40 years. The overall miscarriage rate per pregnancy was 13.61%. When stratified by patient age, there was no correlation between miscarriage rate and antral follicle count. CONCLUSION(S): AFC is not a predictor of pregnancy or miscarriage rates in patients undergoing unstimulated TDI.

Personalized prediction of first-cycle in vitro fertilization success.

OBJECTIVE: To test whether the probability of having a live birth (LB) with the first IVF cycle (C1) can be predicted and personalized for patients in diverse environments. DESIGN: Retrospective validation of multicenter prediction model. SETTING: Three university-affiliated outpatient IVF clinics located in different countries. PATIENT(S): Using primary models aggregated from >13,000 C1s, we applied the boosted tree method to train a preIVF-diversity model (PreIVF-D) with 1,061 C1s from 2008 to 2009, and validated predicted LB probabilities with an independent dataset comprising 1,058 C1s from 2008 to 2009. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Predictive power, reclassification, receiver operator characteristic analysis, calibration, dynamic range. RESULT(S): Overall, with PreIVF-D, 86% of cases had significantly different LB probabilities compared with age control, and more than one-half had higher LB probabilities. Specifically, 42% of patients could have been identified by PreIVF-D to have a personalized predicted success rate >45%, whereas an age-control model could not differentiate them from others. Furthermore, PreIVF-D showed improved predictive power, with 36% improved log-likelihood (or 9.0-fold by log-scale; >1,000-fold linear scale), and prediction errors for subgroups ranged from 0.9% to 3.7%. CONCLUSION(S): Validated prediction of personalized LB probabilities from diverse multiple sources identify excellent prognoses in more than one-half of patients.

Evolutionary conservation of the oocyte transcriptome among vertebrates and its implications for understanding human reproductive function.

Cross-phylum and cross-species comparative transcriptomic analyses provide an evolutionary perspective on how specific tissues use genomic information. A significant mRNA subset present in the oocytes of most vertebrates is stabilized or stored for post-LH surge use. Since transcription is arrested in the oocyte before ovulation, this RNA is important for completing maturation and sustaining embryo development until zygotic genome activation. We compared the human oocyte transcriptome with an oocyte-enriched subset of mouse, bovine and frog (Xenopus laevis) genes in order to evaluate similarities between species. Graded temperature stringency hybridization on a multi-species oocyte cDNA array was used to measure the similarity of preferentially expressed sequences to the human oocyte library. Identity analysis of 679 human orthologs compared with each identified official gene symbol found in the subtractive (somatic-oocyte) libraries comprising our array revealed that bovine/human similarity was greater than mouse/human or frog/human similarity. However, based on protein sequence, mouse/human similarity was greater than bovine/human similarity. Among the genes over-expressed in oocytes relative to somatic tissue in Xenopus, Mus and Bos, a high level of conservation was found relative to humans, especially for genes involved in early embryonic development.

Identification of follicular marker genes as pregnancy predictors for human IVF: new evidence for the involvement of luteinization process.

Multiple pregnancy represents an important health risk to both mother and child in fertility treatment. To reduce a high twin rate, restriction to one embryo transfer is needed. Morphological evaluation methods for predicting embryo viability has significant limitations. Tight communication exists between the follicular cells (FCs) and the oocyte; therefore, developmental competence may be determined by markers expressed in the surrounding FCs. In this study, cells were recovered on a per-follicle basis by individual follicle puncture. Hybridization analysis using a custom-made complementary DNA microarray containing FC transcripts was performed. Genes expressed in FCs associated with good morphological transferred embryos were identified from follicles associated with a pregnancy outcome (pregnancy group) or no pregnancy (non-pregnancy group). Ten candidates from the Pregnancy group and three from the Non-pregnancy group were validated by quantitative RT-PCR. The best predictors associated with pregnancy were UDP-glucose pyrophosphorylase-2 and pleckstrin homology-like domain, family A, member 1. Genes assessment showed no significant candidate genes associated with non-pregnancy outcome, but GA-binding protein transcription factor beta1 showed a tendency to be potentially more expressed in the non-pregnancy group. These markers could be related to granulosa luteinization process and could be used to improve embryo selection for successful single embryo transfer.

A comprehensive assessment of outcomes in pregnancies conceived by in vitro fertilization/intracytoplasmic sperm injection.

OBJECTIVE: To assess the association between in vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI) and adverse birth outcomes. STUDY DESIGN: Retrospective cohort study involved IVF/ICSI patients who were treated in the Ottawa Fertility Centre from 1996 to 2005 with a viable pregnancy (>20 weeks of gestation) and mothers who conceived naturally. RESULTS: Eleven of the 1044 infants conceived with IVF/ICSI (1.1%) and 7 of the 1910 naturally conceived infants (0.4%) had congenital heart defects (P<0.01). Five of the 138 infants (3.6%) born to mothers with a body mass index>30 and conceived by IVF/ICSI had congenital heart defects, compared with none in the 240 infants born to mothers with a body mass index>30 and conceived naturally (P<0.01). CONCLUSION: Infants conceived with use of IVF/ICSI have three times as high a risk of a congenital heart defect as naturally conceived infants.

Genomic assessment of follicular marker genes as pregnancy predictors for human IVF.

Embryo selection efficiency in human IVF procedure is still suboptimal as shown by low pregnancy rates with single embryo transfer (SET). Bidirectional communication between the oocyte and follicular cells (FC) is essential to achieve developmental competence of the oocyte. Differences in the gene expression profile of FCs from follicles leading to pregnancy could provide useful markers of oocyte developmental competence. FCs were recovered by individual follicle puncture. FC expression levels of potential markers were assessed by Q-PCR with an intra-patient and an inter-patient analysis approach. Using gene expression, a predictive model of ongoing pregnancy was investigated. Using intra-patient analysis, four candidate genes, phosphoglycerate kinase 1 (PGK1), regulator of G-protein signalling 2 (RGS2), regulator of G-protein signalling 3 (RGS3) and cell division cycle 42 (CDC42) showed a difference between FCs from follicles leading to a pregnancy or developmental failure. The best predictors for ongoing pregnancy were PGK1 and RGS2. Additionally, inter-patient analysis revealed differences in FC expression for PGK1 and CDC42 between follicles leading to a transferred embryo with positive pregnancy results and those with negative results. Both inter-patient and intra-patient approaches must be taken into consideration to delineate gene expression variations in the context of follicular competence. A predictor model using biomarkers could improve the efficiency of predicting developmental competence of oocytes. These new approaches provide useful tools in the context of embryo selection and in the improvement of pregnancy rates with SET.

Identification of differentially expressed markers in human follicular cells associated with competent oocytes.

BACKGROUND: The development of an accurate method for selection of high-quality embryos is essential to achieve high pregnancy rates with single embryo transfer in human IVF. The developmental competence of the oocyte is acquired during follicle maturation and strong communication also exists between the follicular cells (FCs) and the oocytes; thus oocyte developmental competence may be determined by markers expressed in the surrounding FCs. METHODS: From consenting patients (n = 40), FCs were recovered on a per follicle basis by individual follicle puncture. Hybridization analyses using a custom-made complementary DNA microarray containing granulosa/cumulus expressed sequence tags (ESTs) from subtracted libraries and an Affymetrix GeneChip were performed to identify specific genes expressed in follicles leading to a pregnancy. The selected candidate genes were validated by quantitative-PCR (Q-PCR). RESULTS: Subtractive libraries prepared from pooled samples representing pregnant versus non-pregnant patients produced 1694 ESTs. Hybridization data analysis discriminated 115 genes associated with competent follicles. Selected candidates were confirmed by Q-PCR: 3-beta-hydroxysteroid dehydrogenase 1 (P = 0.0078), Ferredoxin 1 (P = 0.0203), Serine (or cysteine) proteinase inhibitor clade E member 2 (P = 0.0499), Cytochrome P450 aromatase (P = 0.0359) and Cell division cycle 42 (P = 0.0396). CONCLUSIONS: Microarray technologies are useful to mine the transcriptome of FCs expressed in follicles associated with competent oocytes and could be used to improve embryo selection with the objective of successful single embryo transfer.

Towards a more precise assay of sperm function in egg binding.

Historically, the treatment of severe male factor infertility has relied on donor sperm insemination. A decade ago the option of treating severe male factor infertility with partner sperm became a viable alternative. With the introduction of intracytoplasmic sperm injection (ICSI) in conjunction with in vitro fertilization (IVF), only men who produce no sperm are denied the option of fathering their own children. The use of ICSI has been extended to couples with mild male factors. Despite the known genetic risks (both inherent and de novo) of ICSI to offspring, couples with male factors as part of their infertility problem often prefer ICSI to standard IVF, due to apprehension that their sperm might not otherwise succeed in fertilization. This apprehension would be alleviated if an assay for the egg binding capability of human sperm were available. We examine here the possibility that recombinant human zona pellucida 3 (rec hZP3), the primary sperm receptor sulfoglycoprotein of the egg zona pellucida (ZP), be used as a human ZP surrogate for assessing sperm ability to bind to the ZP. Unlike human eggs, which cannot be obtained for this purpose, rec hZP3 can be produced in quantity. An efficient assay can be established by incubating sperm with rec hZP3 coated to a microwell plate. Infertile men with sperm having ability to bind to rec hZP3 can be advised to select standard IVF or intrauterine insemination, which have fewer genetic and medical risks.