Effect of controlled ovarian hyperstimulation in IVF on endometrial gene expression profiles

The impact of ovarian stimulation on the human endometrial microenvironment

STUDY QUESTION

How does ovarian stimulation (OS), which is used to mature multiple oocytes for ART procedures, impact the principal cellular compartments and transcriptome of the human endometrium in the periovulatory and mid-secretory phases?

SUMMARY ANSWER

During the mid-secretory window of implantation, OS alters the abundance of endometrial immune cells, whereas during the periovulatory period, OS substantially changes the endometrial transcriptome and impacts both endometrial glandular and immune cells.

WHAT IS KNOWN ALREADY

Pregnancies conceived in an OS cycle are at risk of complications reflective of abnormal placentation and placental function. OS can alter endometrial gene expression and immune cell populations. How OS impacts the glandular, stromal, immune, and vascular compartments of the endometrium, in the periovulatory period as compared to the window of implantation, is unknown.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study carried out between 2020 and 2022 included 25 subjects undergoing OS and 25 subjects in natural menstrual cycles. Endometrial biopsies were performed in the proliferative, periovulatory, and mid-secretory phases.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Blood samples were processed to determine serum estradiol and progesterone levels. Both the endometrial transcriptome and the principal cellular compartments of the endometrium, including glands, stroma, immune, and vasculature, were evaluated by examining endometrial dating, differential gene expression, protein expression, cell populations, and the three-dimensional structure in endometrial tissue. Mann-Whitney U tests, unpaired t-tests or one-way ANOVA and pairwise multiple comparison tests were used to statistically evaluate differences.

MAIN RESULTS AND THE ROLE OF CHANCE

In the periovulatory period, OS induced high levels of differential gene expression, glandular-stromal dyssynchrony, and an increase in both glandular epithelial volume and the frequency of endometrial monocytes/macrophages. In the window of implantation during the mid-secretory phase, OS induced changes in endometrial immune cells, with a greater frequency of B cells and a lower frequency of CD4 effector T cells.

LARGE SCALE DATA

The data underlying this article have been uploaded to the Genome Expression Omnibus/National Center for Biotechnology Information with accession number GSE220044.

LIMITATIONS, REASONS FOR CAUTION

A limited number of subjects were included in this study, although the subjects within each group, natural cycle or OS, were homogenous in their clinical characteristics. The number of subjects utilized was sufficient to identify significant differences; however, with a larger number of subjects and additional power, we may detect additional differences. Another limitation of the study is that proliferative phase biopsies were collected in natural cycles, but not in OS cycles. Given that the OS cycle subjects did not have known endometrial factor infertility, and the comparisons involved subjects who had a similar and robust response to stimulation, the findings are generalizable to women with a normal response to OS.

WIDER IMPLICATIONS OF THE FINDINGS

OS substantially altered the periovulatory phase endometrium, with fewer transcriptomic and cell type-specific changes in the mid-secretory phase. Our findings show that after OS, the endometrial microenvironment in the window of implantation possesses many more similarities to that of a natural cycle than does the periovulatory endometrium. Further investigation of the immune compartment and the functional significance of this cellular compartment under OS conditions is warranted.

STUDY FUNDING/COMPETING INTERESTS

Research reported in this publication was supported by the National Institute of Allergy and Infectious Diseases (R01AI148695 to A.M.B. and N.C.D.), Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01HD109152 to R.A.), and the March of Dimes (5-FY20-209 to R.A.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or March of Dimes. All authors declare no conflict of interest.

The "freeze-all" strategy seems to improve the chances of birth in adenomyosis-affected women

OBJECTIVE

To compare assisted reproductive technologies (ARTs) outcomes between fresh vs. freeze-all strategies in infertile women affected by adenomyosis.

DESIGN

A single-center observational study.

SETTINGS

University hospital-based research center.

PATIENTS

Adenomyosis-affected women undergoing blastocyst embryo transfer after in vitro fertilization and intracytoplasmic sperm injection between January 1, 2018, and November 31, 2021. The diagnosis of adenomyosis was based on imaging criteria (i.e., transvaginal ultrasound and/or magnetic resonance imaging).

INTERVENTION(S)

Women who underwent a freeze-all strategy were compared with those who underwent a fresh embryo transfer (ET) strategy.

MAIN OUTCOME MEASURE(S)

Cumulative live birth rate (LBR).

RESULTS

A total of 306 women were included in the analysis: 111 in the fresh ET group and 195 in the freeze-all group. The adenomyosis phenotype (internal diffuse adenomyosis, external focal adenomyosis, and adenomyoma) was not significantly different between the two groups. The cumulative LBR (86 [44.1%] vs. 34 [30.6%], respectively), and the cumulative ongoing pregnancy rate (88 [45.1%] vs. 36 [32.4%], respectively) were significantly higher in the freeze-all group compared with the fresh ET group. After multivariate logistic regression analysis, the freeze-all strategy in women with adenomyosis was associated with significantly higher odds of live birth compared with fresh ET (odds ratio = 1.80; 95% confidence interval = 1.02-3.16).

CONCLUSION

The freeze-all strategy in women afflicted with adenomyosis undergoing ART was associated with significantly higher cumulative LBRs. Our preliminary results suggest that the freeze-all strategy is an attractive option that increases ART success rates. Additional studies, with a randomized design, should be conducted to further test whether the freeze-all strategy enhances the pregnancy rate in adenomyosis-affected women.

Expression profile analysis of LncRNAs and mRNAs in pre-receptive endometrium of women with polycystic ovary syndrome undergoing in vitro fertilization-embryo transfer

BACKGROUND

To compare the expression levels of long non-coding RNA (lncRNA) and messenger RNA (mRNA) in pre-receptive endometrium between patients with Polycystic Ovary Syndrome (PCOS)and normal ovulation undergoing in vitro fertilization-embryo transfer (IVF-ET).

METHODS

Endometrial tissues were collected with endometrial vacuum curette in pre-receptive phase (3 days after oocytes retrieval) from PCOS and control groups. LncRNAs and mRNAs of endometrium were identified via RNA sequencing and alignments. A subset of 9 differentially expressed lncRNAs and 11 mRNAs were validated by quantitative reverse transcription polymerase chain reaction(qRT-PCR)in 22 PCOS patients and 18 ovulation patients. The function of mRNAs with differential expression patterns were explored using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).

RESULTS

We found out 687 up-regulated and 680 down-regulated mRNAs, as well as 345 up-regulated and 63 down-regulated lncRNAs in the PCOS patients in contrast to normal ovulation patients. qRT-PCR was used to detect the expression of 11 mRNAs, and validated that the expression of these 6 mRNAs CXCR4, RABL6, OPN3, SYBU, IDH1, NOP10 were significantly elevated among PCOS patients, and the expression of ZEB1 was significantly decreased. qRT-PCR was performed to detect the expression of 9 lncRNAs, and validated that the expression of these 7 lncRNAs IDH1-AS1, PCAT14, FTX, DANCR, PRKCQ-AS1, SNHG8, TPT1-AS1 were significantly enhanced among PCOS patients. Bioinformatics analysis showed that differentially expressed genes (DEGs) involved KEGG pathway were tyrosine metabolism, PI3K-Akt pathway, metabolic pathway, Jak-STAT pathway, pyruvate metabolism, protein processing in endoplasmic reticulum, oxidative phosphorylation and proteasome. The up-regulation of GO classification was involved in ATP metabolic process, oxidative phosphorylation, RNA catabolic process, and down-regulation of GO classification was response to corticosteroid, steroid hormone, and T cell activation.

CONCLUSION

Our results determined the characteristics and expression profile of endometrial lncRNAs and mRNAs in PCOS patients in pre-receptive phase, which is the day 3 after oocytes retrival. The possible pathways and related genes of endometrial receptivity disorders were found, and those lncRNAs may be developed as a predictive biomarker of endometrium in pre-receptive phase.

Which transfer day results in the highest live birth rate for PCOS patients undergoing in vitro fertilization?

BACKGROUND

Polycystic ovary syndrome (PCOS) has unusual levels of hormones. The hormone receptors in the endometrium have a hostile effect and make the microenvironment unfavorable for embryo implantation. The use of gonadotropin stimulation during in vitro fertilization (IVF) may have an impact on embryo implantation and live birth rate. According to recent data, the clinical results of day 4 embryo transfer (D4 transfer) were on par with those of day 5 embryo transfer (D5 transfer) in IVF-ET. There are few studies comparing the outcomes of transplants with various etiologies and days. The purpose of this study was to determine which transfer day had the best result for PCOS patients undergoing IVF.

METHODS

This retrospective cohort study was conducted in the Xingtai Infertility Specialist Hospital between January 2017 and November 2021. A total of 1,664 fresh ART cycles met inclusion criteria, including 242 PCOS transfers and 1422 tubal factor infertility transfers.

CONCLUSIONS

PCOS individuals had the highest live birth rate on D4 transferred. It was not need to culture embryos to blastocysts to optimize embryo transfer for PCOS women. This could be a novel approach to transplantation for PCOS.

The molecular mechanism of naringin improving endometrial receptivity of OHSS rats

Controlling ovarian hyperstimulation syndrome (OHSS) in the controlled ovarian hyperstimulation treatment is necessary to increase the implantation success rate. This study aimed to explore the effect of naringin on the endometrial receptivity of OHSS rats. Female rats were randomly assigned to six groups: Blank, model, low-dose naringin (100 mg/kg/day), medium-dose naringin (200 mg/kg/day), high-dose naringin (400 mg/kg/day), and positive (0.18 mg/kg/day estradiol valerate) groups. Except for the blank group, rats established the OHSS model on Day 7, and their treatments were from Day 0 to 14, separately. Hematoxylin and eosin, immunohistochemical, and scanning electron microscopy were performed to detect the naringin effects on the endometrial receptivity of the OHSS model. Next, circRNAs transcriptome analysis was performed to screen circRNAs. Western blot analysis and real-time quantitative PCR were used to verify it. Our study showed that naringin treatments increased embryo number, endometrial thickness, pinopodes number, and Ki67 expression in the OHSS rats. Moreover, the result of circRNAs transcriptome sequencing showed that naringin significantly inhibited the rnocirc_008140 expression in the OHSS rats and significantly inhibited the changes of 28 gene ontology terms and three Kyoto Encyclopedia of Genes and Genomes pathways which were induced by OHSS. Abcc4 and Rps6ka5 genes were the enriched genes of those pathways. Finally, 24 miRNA target genes of rnocirc_008140 were predicted. Our study showed that naringin significantly improved the endometrial receptivity of OHSS rats to increase the embryo implantation success by reducing rnocirc_008140-adsorbed miRNAs to regulate Abcc4 and Rps6ka5 expression.

The Ratio of Serum Progesterone (P4) to the Number of Follicles (P4/follicle) is a More Objective Parameter for Euploidy Rate as Compared to Systemic Progesterone Levels

Does the late follicular phase progesterone (P4) and the P4-to-follicle-ratio affect the ploidy state of the biopsied embryos? A retrospective observational study conducted at ART Fertility Clinics Abu Dhabi and Muscat, including all stimulation cycles performed between January 2015 and December 2019. In total, 975 cycles were considered for this study. Inclusion criteria were ovarian stimulation due to primary/secondary infertility, patient's age between 18 and 45 years, ICSI as fertilization method, and patients undergoing preimplantation genetic testing for aneuploidies (PGT-A). Patients with testicular sperm extraction (TESE) and warmed oocytes were excluded. Our results have shown that progesterone had no effect on the euploid rate (p = 0.371). However, when adding the ratio of P4 to the number of follicles that were bigger than 10 mm in the last scan, a negative effect on the euploid rate (p < 0.05) was observed. This study was able to show that the use of only P4 is unable to predict ploidy outcomes. However, by including the number of follicles > 10 mm, a clear association was observed between P4/Foll ratio and euploid rate per cycle. The use of both parameters could aid clinicians in their decision to trigger a patient or continue stimulation. Further prospective studies are warranted to confirm those results.

Effect of Chinese patent medicine Kunling Pill on endometrial receptivity: A clinical trial, network pharmacology, and animal-based study

Although pregnancy success rates are raised with assisted reproductive technology, it still cannot meet clinical demands. Kunling Pill (KLP), a traditional Chinese medicine, is widely used in various gynecological disorders, particularly in improving fertility and pregnancy rates. However, the underlying mechanism of how KLP affects pregnancy outcomes remains unclear. This study aimed to explore the effects and mechanisms of KLP on endometrial receptivity. Firstly, a retrospective trial was conducted to validate the efficacy of KLP on repeated implantation failure (RIF) patients. The result indicated a significant increase in the proportion of live birth in KLP group (30.56%) compared to the control group (16.89%). Secondly, network pharmacology methods predicted the active components and network targets of KLP. Endometrial receptivity is closely associated with the activation of inflammatory factors, predicting the function of KLP on the immune system. The estrogen and apoptotic signaling pathways were also highlighted in the gene ontology enrichment analysis. Thirdly, a decreased endometrial receptivity model was established by controlled ovarian hyperstimulation (COH) in female C57BL/6 mice, divided into the COH and KLP groups. Normal female mice are as control group. In vivo, KLP administration could increase endometrial thickness and the number of endometrial glands and pinopodes. In the endometrium, KLP supplementation upregulated the expressions of estrogen receptor α, progesterone receptor, endothelial nitric oxide synthase, and integrin αVβ3 in the murine uterus and reduced serum levels of estrogen and progesterone. KLP regulated the uterine immune cells and inhibited cell apoptosis in the ovary via Bcl-2/Bax/caspase-3 pathway. In conclusion, KLP administration raised the live birth rate in RIF patients to optimize medication regimens, mainly because KLP ameliorated impaired endometrial receptivity.

Transcriptomic patterns in early-secretory and mid-secretory endometrium in a natural menstrual cycle immediately before in vitro fertilization and embryo transfer

OBJECTIVE

This study aimed to evaluate the endometrial transcriptomic patterns in the early secretory phase (ESP) and mid-secretory phase (MSP) of the natural menstrual cycle before in vitro fertilization and embryo transfer (IVF-ET).

METHODS

Thirty patients whose endometrial tissues were obtained from the ESP or MSP of a natural menstrual cycle immediately before IVF-ET were included. Endometrial dating was histologically confirmed as ESP (cycle days 16-18) or MSP (cycle days 19-21), according to the noyes criteria. The patients were divided into two groups depending on the IVF-ET outcome: pregnant (n=14; 7 in ESP and 7 in MSP) or non-pregnant (n=16; 8 in ESP and 8 in MSP). Differentially expressed genes (DEGs) in the MSP, compared to the ESP, were identified using NanoString nCounter (NanoString Technologies, Seattle, WA, USA) data for both the pregnant and non-pregnant groups.

RESULTS

Thirteen DEGs in the pregnant group and 11 DEGs in the non-pregnant group were identified in the MSP compared to those in the ESP. In both groups, adrenoceptor alpha 2A, interleukin 1 receptor-associated kinase 2, a disintegrin and metalloproteinase with thrombospondin repeats 15 (ADAMTS15), serpin family E member 1, integrin subunit beta 3, transmembrane protein 252 (TMEM252), huntingtin associated protein 1, C2 calcium-dependent domain containing 4A, and integrin subunit alpha 2 were upregulated in the MSP, compared to the ESP. TMEM37, galactosidase beta 1 like 2, Rho family GTPase 3, and cytochrome P450 family 24 subfamily A member 1 were upregulated in the MSP only in the pregnant group. ADAMTS8 was downregulated and monoamine oxidase A was upregulated in the MSP only in the non-pregnant group.

CONCLUSION

Transcriptomic patterns in the endometrium immediately before IVF-ET appear to differ according to the IVF-ET outcome. These novel DEGs, which have not been previously studied, may have functional significance during the window of implantation and serve as potential biomarkers of endometrial receptivity.

Chromosomal analysis of 262 miscarried conceptuses: a retrospective study

BACKGROUND

Embryonic chromosomal abnormality is one of the significant causative factors of pregnancy loss. Our goal was to investigate the differences of chromosomal abnormality between different conception modes in miscarried products of conception (POCs).

METHODS

A retrospective study included 262 miscarried POCs from 167 women undergoing assisted reproductive treatment (ART) and 95 spontaneous pregnant (SP) women during March 2019 to March 2022 in Renmin Hospital of Wuhan University. Subgroups were divided according to age, fertilization method, types and stages of embryo transfer. The profiles of cytogenetic abnormalities in the miscarried POCs were measured via next-generation sequencing.

RESULTS

The rate of chromosomal abnormality in the fresh embryo transfer group and the cleavage embryo transfer group was significantly higher than that in the frozen embryo transfer group (79.2% vs. 36%, P = 0.0001) and the blastocyst transfer group (66.7% vs. 32.1%, P = 0.0001) respectively. There was no significant difference in the rate of chromosomal abnormalities when compared by maternal age (49.2% vs. 62%, P = 0.066), types of conception (49.7% vs. 57.9%, P = 0.202), fertilization method (49.6% vs. 48.7%, P = 0.927) and frequency of abortion (56% vs. 47.6%, P = 0.183). However, the women aged ≥ 35 years had more frequent numerical abnormality (P = 0.002); patients using assisted reproductive technology had more rate of chromosomal structural abnormalities (26.5% vs. 7.3%, P = 0.005); the ICSI fertilization group has more frequency of deletion/microdeletion than the IVF fertilization group (80% vs. 31.3%, P = 0.019).

CONCLUSION

Blastocyst transfer might help to reduce the incidence of miscarriage. In addition, "freezing all" should be considered if encountered hyper ovarian stimulation, to avoid the negative effect of high estrogen environment on embryo development. The higher incidence of structural abnormalities in miscarried POCs from assisted reproductive patients reminds us to pay attention to the safety of the technology for offspring.

The association between embryo storage time and treatment success in women undergoing freeze-all embryo transfer

OBJECTIVE

To investigate the relationship between the embryo frozen time and live birth rate (LBR) in women having a freeze-all cycle.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PATIENT(S)

Women who underwent their first vitrified-warmed cycles from January 2013 to December 2019.

INTERVENTION(S)

Embryo storage time.

MAIN OUTCOME MEASURE(S)

The primary outcome was the LBR.

RESULT(S)

A total of 14,928 women were eligible for the analysis. Women with the frozen time of transferred embryos for 2-5 months were associated with a higher LBR compared with other groups. The results were confirmed by an inverted U curve in the restricted cubic splines before as well as after adjustment for covariables, which suggested that an embryo storage time of 3-4 months was associated with the highest LBR. Subgroup analyses demonstrated that the inverted U curve relationship between embryo storage time and LBR was only observed in women with the high response. Sensitivity analyses in women with at least one good-quality embryo for transfer, in women aged <36 years at embryo transfer, or in women with double cleavage embryo transfer showed that the association remained valid. The association was weakened in women with single blastocyst transfer probably because of the small sample size in these women.

CONCLUSION(S)

An inverted U-shaped relationship was found between embryo storage time and treatment success in women with high ovarian response in freeze-all embryo transfer cycles. Prolonged storage time of >6 months was associated with reduced pregnancy rates.

Association of embryo transfer type with infertility in endometriosis: a systematic review and meta-analysis

PURPOSE

The study aims to evaluate whether frozen embryo transfer can restore optimal receptivity leading to better assisted reproductive technology outcomes in women with endometriosis.

METHODS

This systematic review and meta-analysis, conducted from January 10, 2021 to July 1, 2021, searched the Cochrane Library, PubMed, Embase, Web of Science, OVID, and Clinicaltrials.gov databases from inception to January 10, 2021. The search strategy combined search terms as follows: ("endometriosis" OR "deep endometriosis" OR "endometrioma") AND ("frozen-thawed embryo transfer" OR "frozen embryo transfer" OR "freeze-all strategy") AND ("pregnancy outcome" OR "live birth rate" OR "clinical pregnancy rate" OR "miscarriage rate"). No publication time or language limits were set during the searches. In addition, references of the related articles were searched by hand. Patients were included if they had a history of endometriosis and had received fresh or frozen embryo transfer. Only the first transfer cycle was included. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to express outcomes, and data synthesis was conducted using RevMan, version 5.4 software.

RESULTS

A total of six studies with moderate methodologic quality were retrieved in the meta-analysis. The studies included 3010 women with endometriosis who wanted to conceive; 1777 (59.0%) had frozen embryo transfer, and 1233 (41.0%) had fresh embryo transfer. There was a significantly higher frequency of live births in the frozen embryo group than in the fresh embryo group (OR, 1.53; 95% CI, 1.13-2.08; P = .007). Despite a similar clinical pregnancy rate in the two groups (OR, 1.26; 95% CI, 0.95-1.69; P = .11), the difference in miscarriage rate was significant (OR, 0.70; 95% CI, 0.50-0.97; P = .03). Evidence quality was considered moderate.

CONCLUSION

Cryopreserved embryo transfer has resulted in preferable reproduction outcomes when compared with fresh embryo transfer in patients with endometriosis, but the evidence is not yet abundant. More strictly designed research is needed to evaluate whether frozen embryo transfer leads to better reproductive outcomes in women with endometriosis compared with those receiving fresh embryo transfer.

REGISTRATION NUMBER

PROSPERO CRD42021248313.

Towards an Improved Understanding of the Effects of Elevated Progesterone Levels on Human Endometrial Receptivity and Oocyte/Embryo Quality during Assisted Reproductive Technologies

Ovarian stimulation is an indispensable part of IVF and is employed to produce multiple ovarian follicles. In women who undergo ovarian stimulation with gonadotropins, supraphysiological levels of estradiol, as well as a premature rise in progesterone levels, can be seen on the day of hCG administration. These alterations in hormone levels are associated with reduced embryo implantation and pregnancy rates in IVF cycles with a fresh embryo transfer. This article aims to improve the reader’s understanding of the effects of elevated progesterone levels on human endometrial receptivity and oocyte/embryo quality. Based on current clinical data, it appears that the premature rise in progesterone levels exerts minimal or no effects on oocyte/embryo quality, while advancing the histological development of the secretory endometrium and displacing the window of implantation. These clinical findings strongly suggest that reduced implantation and pregnancy rates are the result of a negatively affected endometrium rather than poor oocyte/embryo quality. Understanding the potential negative impact of elevated progesterone levels on the endometrium is crucial to improving implantation rates following a fresh embryo transfer. Clinical studies conducted over the past three decades, many of which have been reviewed here, have greatly advanced our knowledge in this important area.

Placental pathology of term singleton live births conceived with fresh embryo transfer compared with those conceived without assisted reproductive technology

OBJECTIVE

To compare placental pathology from term singleton live births conceived with fresh embryo transfer vs. those conceived without assisted reproductive technology (ART).

DESIGN

Retrospective cohort study.

SETTING

Academic fertility center.

PATIENT(S)

Women with a term singleton live birth who conceived after fresh autologous in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles (ART group) and those who conceived without ART.

INTERVENTION(S)

An experienced placental pathologist categorized placental pathology as anatomic, inflammatory, or vascular. Patient characteristics were compared by chi-squared tests, Student's t-test, or nonparametric tests. Multivariate logistic regression models were used to compare placental pathology between pregnancies conceived with and without ART.

MAIN OUTCOME MEASURE(S)

Incidence of anatomic, inflammatory, and vascular placental pathology.

RESULT(S)

There was a higher incidence of placental pathology in the ART group (n = 511) than in the non-ART group (n = 121), specifically anatomic (adjusted odds ratio [aOR] 2.50, 95% confidence interval [CI] 1.42-4.40) and vascular (aOR 2.00, 95% CI 1.13-3.53) pathology. These findings were driven primarily by the significantly higher odds of anatomic (aOR 2.97, 95% CI 1.55-5.66) and vascular (aOR 1.98, 95% CI 1.04-3.75) pathology observed in ICSI pregnancies. Single blastocyst transfers remained associated with increased anatomic pathology (ART: aOR 4.89, 95% CI 2.28-10.49; ICSI: aOR 3.38, 95% CI 1.49-7.71).

CONCLUSION(S)

Fresh embryo transfer is associated with increased anatomic and vascular placental pathology in term singleton live births compared with conception without ART. This finding should be investigated prospectively in a larger cohort of patients.

Basic aspects of endometrial receptivity in PCOS patients

Polycystic Ovarian Syndrome (PCOS) is an endocrine disorder commonly affecting the reproductive capacity of women leading to infertility. PCOS-related infertility is majorly due to anovulation; however, it is not the only cause. The defective endometrium causing recurrent miscarriage and implantation failure can also be accountable for infertility in PCOS women. The unusual levels of hormones and their receptors in the PCOS endometrium have a hostile effect during WOI, making the microenvironment unfavorable for embryo implantation. To date, many studies have been performed to determine the role of candidate genes in endometrial receptivity but very limited data is available using whole genome approach. This review aims at summarizing the existing studies on the basic aspects of endometrial receptivity in PCOS. The review focuses on aberrant levels of hormones and their receptors in the endometrium, affecting the receptivity. Additionally, it explores the novel approach reviewing the effect on treatment options administered for ovulation induction in PCOS on their endometrial receptivity. Overall, this review will help us to understand the molecular milieu in PCOS endometrium and its effect on the receptivity potential. However, to have a thorough understanding of the mechanistic approach of hormonal imbalance in PCOS on endometrial receptivity, there is a need to give more weightage to genome-wide studies in the future. The current review will further guide us to formulate future studies using whole genome technologies for the assessment of endometrial receptivity in different cohorts of PCOS women, which may have future diagnostic implementations.

Pregnancy Outcomes of Different Endometrial Preparation in Patients With a History of Cesarean Section

OBJECTIVE

To investigate the efficacies of three cycle regimens in women receiving frozen embryo transfer with a history of cesarean section: natural cycle treatment, hormone replacement therapy and treatment with gonadotropin-releasing hormone agonist.

DESIGN

Retrospective cohort study.

METHODS

patients (N = 6,159) with a history of caesarean section who fulfilled the inclusion criteria were enrolled in the study from January 2014 to December 2019 at the CITIC-Xiangya Hospital of Reproduction and Genetics. Reproductive outcomes of patients in the natural cycle (n = 4,306) versus hormone replacement therapy (n = 1,007) versus gonadotropin-releasing hormone agonist + hormone replacement therapy groups (n = 846) were compared. Continuous data were analyzed using Student's t-test, and categorical variables were analyzed using the χ2 test. Multivariable logistic regression was used to evaluate the possible relationships between the types of endometrial preparation and pregnancy outcomes after adjusting for confounding factors.

RESULTS

The unadjusted odds of the miscarriage rate of singleton pregnancies were significantly higher in the hormone replacement therapy compared with the natural cycle (25.5% versus 20.4%, respectively). After adjusting for possible confounding factors, the early miscarriage rate and the miscarriage rate of singleton pregnancies remained significantly higher in the hormone replacement therapy than the natural cycle. The clinical pregnancy rates in the natural cycle, hormone replacement therapy and gonadotropin- releasing hormone agonist + hormone replacement therapy of women with a history of cesarean section was 48.8%, 48% and 47.1%, respectively, and the live birth rates were 37%, 34.1% and 35.7%, respectively.

CONCLUSIONS

In women undergoing frozen embryo transfer with a history of cesarean section, hormone replacement therapy for endometrial preparation was associated with a higher early miscarriage rate, albeit after statistical adjustment for confounding factors. However, the risk observed was little and did not influence the overall reproductive performances.

It is not worth postponing frozen embryo transfers after oocyte pickup: A retrospective cohort study based on propensity score matching

This study was to explore whether postponing frozen embryo transfers (FET) after oocyte pickup (OPU) improves clinical and neonatal outcomes. From May 2018 to Dec 2020, a total of 1109 patients underwent their first OPU cycles adopting a non-selective freeze-all policy were included in this retrospective cohort study. In the immediate group (n=219), patients underwent FET in the first menstrual cycle after OPU, and patients in the postponed group (n=890) waited for more than 1 menstrual cycle after OPU to perform FET. A propensity score matching (PSM) model was used to evaluate the clinical outcomes and neonatal outcomes between the two groups. There were 209 patients in the immediate group and 499 patients in the postponed one after PSM. Patients waited for a significantly shorter period for FET in the immediate group (30.74 ± 3.85 days) compared with the postponed group (80.39 ± 26.25 days, P<0.01). The clinical pregnancy rate (CPR) and live birth rate (LBR) in the immediate group were 58.4% and 48.3%, respectively, which were comparable to those of the postponed one (58.1%, 49.7%, P > 0.05). No statistical significance was found in the average birth weight (3088.82 ± 565.35 g vs 3038.64 ± 625.78 g, P > 0.05) and height (49.08 ± 1.87 cm vs 49.30 ± 2.52 cm) of neonates between the two groups. The gender ratio, the incidence of macrosomia and low birth weight did not differ significantly between the two groups. In conclusion, postponing FET does not improve clinical and neonatal outcomes. If patients have no contraindications, FETs should be carried out immediately after OPU.

Histopathological profile of women who had previously failed IVF and the association to the outcome in the subsequent IVF cycle

Objective

To evaluate the endometrial histopathological profile of patients undergoing curettage and the association of the histopathological profile with the pregnancy outcome during the subsequent IVF cycle.

Methods

In this retrospective cohort study, a total of 248 women with at least one failed attempt of IVF and who underwent curettage and a subsequent IVF were included. Demographic data, endometrial histopathological records, stimulation information, and pregnancy outcomes were collected and analyzed.

Results

The histopathological analysis of endometrial tissues showed that 130 women (52.4%) had endometrial pathologies. Of these women, 103 (41.5%) had endometrial polyps, 22 (8.9%) had chronic endometritis, and five (2.0%) had both polyps and endometritis. No statistical difference was observed between the normal histopathology group and the abnormal histopathology group in the outcome of the subsequent IVF cycle. Subgroup analyses were performed to further characterize and compare women with normal histopathology and women with endometrial polyps (polyp subgroup) or chronic endometritis (endometritis subgroup). No statistical differences were found among the three groups in the rates of pregnancy (44.1% vs. 49.5% vs. 45.5%, P=0.72), biochemical pregnancy loss (13.5% vs. 15.7% vs. 20.0%, P=0.86), clinical pregnancy loss (25.0% vs. 31.4% vs. 30.0%, P=0.77), and live birth (27.1% vs. 26.2% vs. 22.7%, P=0.91) during the subsequent IVF cycle.

Conclusion

Women with previously failed IVF and abnormal endometrial histopathology treated with curettage had the same outcome in the subsequent IVF cycle as women with normal endometrial histopathology.

A review of the pathophysiology of recurrent implantation failure

Implantation is a critical step in human reproduction. The success of this step is dependent on a competent blastocyst, receptive endometrium, and successful cross talk between the embryonic and maternal interfaces. Recurrent implantation failure is the lack of implantation after the transfer of several embryo transfers. As the success of in vitro fertilization has increased and failures have become more unacceptable for patients and providers, the literature on recurrent implantation failure has increased. While this clinical phenomenon is often encountered, there is not a universally agreed-on definition-something addressed in an earlier portion of this Views and Reviews. Implantation failure can result from several different factors. In this review, we discuss factors including the maternal immune system, genetics of the embryo and parents, anatomic factors, hematologic factors, reproductive tract microbiome, and endocrine milieu, which factors into embryo and endometrial synchrony. These potential causes are at various stages of research and not all have clear implications or immediately apparent treatment.

Freeze-all policy for in vitro fertilization in women with normal response to ovarian stimulation

Objective

To answer the question if the freeze-all strategy and subsequent frozen embryo transfer is preferable to fresh embryo transfer for patients with normal response to ovarian stimulation (4 to 15 oocytes recovered) during in vitro fertilization treatments.

Methods

A retrospective cohort from two human reproduction centers between 2013 and 2017. A total of 471 frozen embryo transfers from freeze-all cycles, and 3,208 fresh transfers were included.

Results

After propensity score matching adjustment for age and number of eggs, 467 freeze-all cycles and 934 fresh cycles were analyzed, revealing no statistically significant difference between groups in relation to clinical pregnancy rate (32.5% in the Freeze-all Group and 32.3% in the Fresh Group, p=0.936). For women aged 40 years and older, we observed a statistically significant higher clinical pregnancy rate when freeze-all strategy was used (29.3% in the Freeze-all Group and 19.8% in the Fresh Group, p=0.04).

Conclusion

Freeze-all strategy was not superior to fresh transfer for all patients with normal response to ovarian stimulation. However, women aged 40 years and older could benefit from this strategy. This deserves further investigation in future research, preferable in a prospective randomized study.

Endometrial Expression of Cell Adhesion Genes in Recurrent Implantation Failure Patients in Ongoing IVF Cycle

Recurrent implantation failure (RIF) is one of the major obstacles in IVF. Transcriptomic literature has revealed the various biological processes involved in endometrial receptivity (ER) under different physiological circumstances, especially in natural cycle. We intended to determine the function-specific ER profile under controlled ovarian stimulation (COS) cycle. This can help to back trace the genomic impairment in RIF patients during the IVF cycle and to validate the genes involved in enriched pathways. In our study, retrospective gene expression microarray dataset was reanalysed after the follow-up, in classic non pregnant RIF (cases) vs fertile women (controls) under COS (n = 5/group). Reanalysis of microarray revealed significant downregulation of cell adhesion function (P:3.11E-05) with the maximum gene count. For validation purpose, downregulation of eight genes (COMP, HABP2, ITGAD, CDH3, COL22A1, MFAP4, THBS1and CD300A) involved in enriched cell adhesion pathway having fold change > 3 were assessed by real-time PCR in independent cohorts of cases and controls (n = 24, each). Downregulation of six out of eight genes (COMP, HABP2, ITGAD, CDH3, MFAP4 and THBS1) were confirmed by real-time PCR (P < 0.05) with fold change > 2. This indicates the importance of analysed genes in the ER mechanism under COS, thus mimicking the fresh embryo transfer. The further analysis in larger cohorts would substantiate the study findings in RIF patients undergoing IVF cycle.

The effect of late-follicular phase progesterone elevation on embryo ploidy and cumulative live birth rates

RESEARCH QUESTION

Does late-follicular phase progesterone elevation have a deleterious effect on embryo euploidy, blastocyst formation rate and cumulative live birth rates (CLBR)?

DESIGN

A multicentre retrospective cross-sectional study including infertile patients aged 18-40 years who underwent ovarian stimulation in a gonadotrophin-releasing hormone antagonist protocol and preimplantation genetic testing for aneuploidies (PGT-A) followed by a freeze-all strategy and euploid embryo transfer between August 2017 and December 2019. The sample was stratified according to the progesterone concentrations on the day of trigger: normal (≤1.50 ng/ml) and high (>1.50 ng/ml). Moreover, sensitivity analyses were performed to determine whether different conclusions would have been drawn if different cut-offs had been adopted. The primary outcome was the embryo euploidy rate. Secondary outcomes were the blastocyst formation rate, the number of euploid blastocysts and CLBR.

RESULTS

Overall 1495 intracytoplasmic sperm injection PGT-A cycles were analysed. Late-follicular phase progesterone elevation was associated with significantly higher late-follicular oestradiol concentrations (2847.56 ± 1091.10 versus 2240.94 ± 996.37 pg/ml, P < 0.001) and significantly more oocytes retrieved (17.67 ± 8.86 versus 12.70 ± 7.00, P < 0.001). The number of euploid embryos was significantly higher in the progesterone elevation group (2.32 ± 1.74 versus 1.86 ± 1.42, P = 0.001), whereas the blastocyst formation rate (47.1% [43.7-50.5%] versus 51.0% [49.7-52.4%]), the embryo euploidy rate (48.3% [44.9-51.7%] versus 49.1% [47.7-50.6%], the live birth rate in the first frozen embryo transfer (34.1% versus 31.1%, P = 0.427) and CLBR (38.9% versus 37.0%, P = 0.637) were not significantly different between the two groups.

CONCLUSIONS

Euploidy rate and CLBR do not significantly differ among PGT-A cycles with and without late-follicular progesterone elevation in a freeze-all approach.

Effect of Endometrial Thickness and duration of Estrogen Supplementation on In Vitro Fertilization-Intracytoplasmic Sperm Injection Outcomes in Fresh Ovum/Embryo Donation Cycles

Background:

There is no consensus regarding optimal endometrial thickness and duration of estrogen supplementation in embryo transfer cycles, at present.

Aims:

To observe the effect of endometrial thickness and/or duration of estrogen supplementation on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) outcomes in fresh ovum/embryo donation cycles.

Settings and Design:

This was a retrospective observational study. The study was conducted from January 2015 to November 2017.

Subjects and Methods:

Nine hundred and fifty seven fresh blastocyst transfer cycles in the recipients of oocyte/embryo donation regardless of reproductive history and diagnosis conducted at Nova IVF Fertility, Ahmedabad, Gujarat, India. Of these, 315 women had single embryo transfer (SET), while 642 had double embryo transfer (DET). Only fresh blastocysts derived from oocytes of young donors (≤30 years) and transferred in a uniform hormone replacement therapy (HRT) cycle were included. The effect of endometrial thickness and duration of estrogen on live birth rate (LBR) and other IVF/ICSI outcomes were analyzed.

Statistical Analysis:

Univariate logistic regression.

Results:

A significant improvement in LBR was noted in the recipients with each millimeter increase in endometrial thickness starting from 6 mm after transfer of either single (odds ratio [OR] = 1.3, P = 0.003) or double (OR = 1.14, P = 0.0218) blastocysts. Lower LBR was observed in recipients having SET and who received estrogen supplementation of <10 days (OR = 0.72; P = 0.02). Implantation rate and clinical pregnancy rate also improved significantly with endometrial thickness, but there was no change in clinical abortion rate and ectopic pregnancy rate.

Conclusions:

After minimizing the possible oocyte factor by including only donor oocytes and that of COH using a uniform HRT protocol, LBR improved with each millimeter increase in endometrial thickness starting from 6 mm. Shorter duration of estrogen supplementation (<10 days) reduced the chances of live birth in recipients after transfer of a single blastocyst.

Lower chromosomal abnormality frequencies in miscarried conceptuses from frozen blastocyst transfers in ART

STUDY QUESTION

Are blastocyst culture and cryopreservation in ART associated with chromosomal abnormalities in miscarried products of conception (POC)?

SUMMARY ANSWER

Frozen blastocyst transfer in women aged 35 years or older and frozen embryo transfer (ET) (including both cleavage-stage embryo and blastocyst) in women aged <35 years are associated with decreased frequencies of embryonic chromosomal abnormalities in miscarried POC.

WHAT IS KNOWN ALREADY

Blastocyst culture and embryo cryopreservation have been previously associated with favorable ART treatment outcomes and widely applied in clinical practice. However, the association between these embryo manipulation procedures and embryonic chromosomal abnormalities has not been evaluated to the best of our knowledge.

STUDY DESIGN, SIZE, DURATION

This retrospective study included a total of 720 patients who underwent IVF/ICSI, and the retained POC were obtained. A single-nucleotide polymorphism (SNP)-based chromosomal microarray analysis (CMA) of all miscarried conceptuses was performed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was based on the Clinical Reproductive Medicine Management System/Electronic Medical Record Cohort Database (CCRM/EMRCD) at our center. In total, 720 miscarried POCs were collected from patients undergoing ART (including fresh cleavage-stage ET, fresh blastocyst transfer, frozen cleavage-stage ET and frozen blastocyst transfer), and the incidences and profiles of cytogenetic abnormalities in the miscarried conceptuses were measured via SNP-based CMA.

MAIN RESULTS AND THE ROLE OF CHANCE

The chromosomal abnormality rate in POC varied from 33.7% to 66.7% among the different ET strategies. In the patients aged ≥35 years, frozen blastocyst transfer was significantly associated with a lower incidence of chromosomal aberrations in the POCs (adjusted odds ratio (aOR): 0.171 (95% CI: 0.040-0.738); P = 0.018) than fresh blastocyst transfer. In the patients aged <35 years, frozen ET was significantly associated with a lower incidence of chromosomal aberrations than fresh ET in both cleavage-stage ET cycles and blastocyst transfers cycles (aOR: 0.545 (0.338-0.879), P = 0.013; and aOR: 0.357 (0.175-0.730), P = 0.005, respectively). Trisomy was the most frequent abnormal embryonic karyotype in the different ET strategies, and its frequency significantly differed among strategies (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study was retrospectively designed, and we cannot draw any definite conclusions from our results regarding the adequate safety of embryo cryopreservation in ongoing pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first study assessing the associations of ET strategies with the probability of miscarriage associated with embryonic chromosomal abnormalities. However, the underlying mechanism of these associations is unknown; this study may promote research concerning ET strategies and promote comprehensive consultations and recommendations for patients.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Natural Science Foundation of China (Grant No.81571409), Science and Technology Research Project of Henan (Grant No. 172102310009) and Medical Science and Technology Research Project of Henan (Grant No. 201701005). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Association between serum estradiol levels prior to progesterone administration in artificial frozen-thawed blastocyst transfer cycles and live birth rate: a retrospective study

OBJECTIVE

To study whether serum estradiol (E2) levels prior to progesterone administration in the artificial endometrial preparation (AEP) of frozen-thawed blastocyst transfer affect the live birth rate.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical centre.

POPULATION

A total of 3857 frozen-thawed blastocyst transfer cycles were divided into three groups: <200 pg/ml (n = 1676); 200-399 pg/ml (n = 1296); and ≥400 pg/ml (n = 885), based on the 25th (182.3 pg/ml) and 75th percentile (390.2 pg/ml) of serum E2 level prior to progesterone administration.

METHODS

Univariable and multivariable logistic regression analysis was performed.

MAIN OUTCOME MEASURES

The primary outcome of the study was the live birth rate and the secondary outcomes included clinical pregnancy rate, pregnancy loss rate, neonatal birthweight, Z-score, and small for gestational age (SGA).

RESULTS

Compared with the reference group, accounting for major covariates, the live birth rate significantly decreased in the '≥400 pg/ml' group (adjusted OR 0.71, 95% CI 0.59-0.85). Compared with the reference group, there was an association between the E2 level in the '≥400 pg/ml' group and a decrease in the clinical pregnancy rate (adjusted OR 0.74, 95% CI 0.61-0.89). Compared with the reference group, the pregnancy loss rate significantly increased in the '≥400 pg/ml' group (adjusted OR 1.45, 95% CI 1.08-1.93). The E2 levels did not affect neonatal birthweight, Z-score, and SGA among singletons.

CONCLUSIONS

High serum E2 levels prior to progesterone administration in AEP are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

TWEETABLE ABSTRACT

High serum E2 levels prior to progesterone administration in artificial FET are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

Effect of gonadotropins and endometrial thickness on pregnancy outcome in patients with unexplained infertility or polycystic ovarian syndrome undergoing intrauterine insemination

Objective

The purpose of this study was to investigate the effect of gonadotropin dose and endometrial thickness (EMT) on pregnancy outcome in patients undergoing intrauterine insemination (IUI).

Methods

We retrospectively analyzed data from 361 patients with unexplained infertility or polycystic ovarian syndrome (PCOS) who underwent 930 IUI cycles treated with gonadotropins. Then, we measured the effects of gonadotropins and EMT on the clinical pregnancy rate. Finally, we assessed the association of various doses of gonadotropins on EMT.

Results

The dose of gonadotropins given and thickness of the endometrium were higher in the pregnancy group than in the nonpregnancy group (636.0 vs. 600.0 IU for gonadotropin dose; 9.15 vs. 8.70 mm for EMT). Clinical pregnancy rates were significantly improved by increasing the dose of gonadotropins (9.1%, <450 IU; 16.2%, 450–599 IU; 18.6%, 600–749 IU, and 17.3%, ≥750 IU), or by increased EMT (0%, <5.0 mm; 12.2%, 5.0–6.9 mm; 15.5%, 7.0–14.0 mm; and 33.3%, >14.0 mm).

Conclusion

Increasing the dose of gonadotropins to stimulate one follicle to develop may benefit endometrial proliferation and improve IUI outcomes.

Supraphysiological estradiol levels on the hCG trigger day are associated with SGA for singletons born from fresh embryo transfer

The effects of supraphysiological estradiol (E2) on neonatal outcomes and the significance of specific E2 concentrations remain unclear. The purpose of this study was to investigate whether supraphysiological E2 levels on the human chorionic gonadotropin (hCG) trigger day are associated with small size for gestational age (SGA) in singletons born from fresh embryo transfer (ET) cycles. Patients with singleton pregnancies who delivered after the transfer of fresh embryos, during the period from July 2012 to December 2017, at our center were included. We excluded cycles involving a vanishing twin, maternal age >35 years, basal follicle-stimulating hormone ≥10 mIU/ml, or anti-Müllerian hormone ≤1 ng/ml. We then divided all cycles into five groups by E2 level on trigger day: group A, <2000 pg/ml (reference group); group B, 2000 pg/ml≤E2<2999 pg/ml; group C, 3000 pg/ml≤E2<3999 pg/ml; group D, 4000 pg/ml≤E2<4999 pg/ml; and group E, ≥5000 pg/ml. The prevalence of SGA among singletons from fresh ET was the primary outcome. The SGA rate significantly increased when the E2 level was ≥4000 pg/ml, as observed by comparing groups D (odds ratio [OR]: 1·79, 95% confidence interval [CI]: 1·16-2·76, P = 0·01) and E (OR: 1·68, 95% CI: 1·10-2·56, P = 0·02) with the reference group. Multivariate logistic regression indicated that a serum E2 level of at least 4000 pg/ml on the hCG trigger day was associated with increased SGA and with significant differences for groups D (adjusted OR [AOR]: 1·65, 95% CI: 1·05-2·59, P = 0·03) and E (AOR: 1·60, 95% CI: 1·03-2·53, P = 0·04) relative to the reference group. In conclusion, in fresh ET cycles, the supraphysiological E2 ≥4000 pg/ml on the hCG trigger day increases the risk of SGA.

Fetal fraction of cell-free DNA in pregnancies after fresh or frozen embryo transfer following assisted reproductive technologies

STUDY QUESTION

Is the fetal fraction (FF) of circulating cell-free DNA (cfDNA) affected in pregnancies following ART treatment with either fresh or frozen embryo transfer (ET) compared with natural conception?

SUMMARY ANSWER

This study shows a significant reduction in the FF in ART patients compared with naturally conceived pregnancies, which seems to be more pronounced after fresh ET compared with frozen ET.

WHAT IS KNOWN ALREADY

Non-invasive prenatal testing (NIPT) is based on cfDNA in maternal blood, of which about 10% is of placental origin and thus represents the fetal karyotype. Validation studies have demonstrated a high sensitivity, specificity and positive predictive value of NIPT for the detection of fetal trisomy 21, 18 and 13. Nevertheless, the FF of cfDNA is an important factor for NIPT test accuracy. Several studies have found a reduction in FF for pregnancies following ART in comparison with natural conception. However, knowledge on how the FF is affected in ART pregnancies after fresh ET compared with frozen ET is very limited.

STUDY DESIGN, SIZE, DURATION

The study was designed as a case-control study. A total of 54 women with an ongoing pregnancy following ART treatment were included. After exclusion for different reasons, statistical analyses were based on 23 NIPT samples from pregnant women treated with fresh ET and 26 NIPT samples from pregnant women treated with frozen-thawed ET in a modified natural cycle. Women were included between February 2018 and November 2018. The results were compared with a control group of 238 naturally conceived pregnancies with a high-risk result from the combined first trimester screening (cFTS).

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from the Fertility Clinics at Copenhagen University Hospital Hvidovre and Copenhagen University Hospital Rigshospitalet. Blood samples for NIPT analysis were drawn between 11 + 0 and 14 + 2 weeks of gestation and were all analyzed at the NIPT Center at Copenhagen University Hospital Hvidovre. The NIPT-test was performed by massive-parallel whole-genome sequencing. The FF was determined using the SeqFF algorithm.

MAIN RESULTS AND THE ROLE OF CHANCE

We found a reduction in FF in ART patients compared with naturally conceived pregnancies, and the reduction was more pronounced for ART pregnancies after fresh ET (mean FF = 0.049) compared with frozen ET (mean FF = 0.063) (multivariate analysis adjusted for maternal BMI, P = 0.02). Another multivariate analysis, adjusted for BMI and multiples of median (MoM) values for pregnancy-associated plasma protein-A (PAPP-A), demonstrated a significantly reduced FF for ART pregnancies (mean FF = 0.056) compared with naturally conceived pregnancies (mean FF = 0.072) (P < 0.0001). We found that FF was significantly reduced with increasing maternal BMI (P < 0.0001) and with decreasing MoM values of PAPP-A (P = 0.003).

LIMITATIONS, REASONS FOR CAUTION

A limitation of our study design was the relatively small sample size. Another limitation was that the control group was not matched with the ART-treated women. The majority of the women from the control group had a high risk from cFTS, thereby their biochemical markers were diverging. However, the biochemical markers for the ART-treated women with fresh or frozen ET were not divergent within the subgroups.

WIDER IMPLICATIONS OF THE FINDINGS

Concurrent with other studies demonstrating a reduced FF for singleton pregnancies after ART treatment compared with naturally conceived pregnancies, we found a reduction in FF between the two groups. This is one of the first studies to examine FF in ART pregnancies after fresh ET compared with frozen ET, hence the existing knowledge is limited. We find that FF is even more reduced in pregnancies following fresh ET compared with frozen ET, which might possibly reflect the predisposition of being small for gestational age after fresh ET compared with natural cycle frozen ET.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the A.P. Møller og Hustru Chastine Mc-Kinney Møllers Fond til almene Formaal (the A.P. Møller Foundation for General Purposes). All authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

NA.

The proliferative phase endometrium in IVF/ICSI: an in-cycle molecular analysis predictive of the outcome following fresh embryo transfer

STUDY QUESTION

Does an early proliferative phase endometrial biopsy harvested during ovarian stimulation harbour information predictive of the outcome following fresh embryo transfer (ET) in that same cycle?

SUMMARY ANSWER

Transcriptome analysis of the whole-tissue endometrium did not reveal significant differential gene expression (DGE) in relation to the outcome; however, the secretome profile of isolated, cultured and in vitro decidualized endometrial stromal cells (EnSCs) varied significantly between patients who had a live birth compared to those with an implantation failure following fresh ET in the same cycle as the biopsy.

WHAT IS KNOWN ALREADY

In the majority of endometrial receptivity research protocols, biopsies are harvested during the window of implantation (WOI). This, however, precludes ET in that same cycle, which is preferable as the endometrium has been shown to adapt over time. Endometrial biopsies taken during ovarian stimulation have been reported not to harm the chances of implantation, and in such biopsies DGE has been observed between women who achieve pregnancy versus those who do not. The impact of the endometrial proliferative phase on human embryo implantation remains unclear, but deserves further attention, especially since in luteal phase endometrial biopsies, a transcriptional signature predictive for repeated implantation failure has been associated with reduced cell proliferation, possibly indicating proliferative phase involvement. Isolation, culture and in vitro decidualization (IVD) of EnSCs is a frequently applied basic research technique to assess endometrial functioning, and a disordered EnSC secretome has previously been linked with failed implantation.

STUDY DESIGN, SIZE, DURATION

This study was nested in a randomized controlled trial (RCT) investigating the effect of endometrial scratching during the early follicular phase of ovarian stimulation on clinical pregnancy rates after IVF/ICSI. Of the 96 endometrial biopsies available, after eliminating those without fresh ET and after extensive matching in order to minimize the risk of potential confounding, 18 samples were retained to study two clinical groups: nine biopsies of patients with a live birth versus nine biopsies of patients with an implantation failure, both following fresh ET performed in the same cycle as the biopsy. We studied the proliferative endometrium by analysing its transcriptome and by isolating, culturing and decidualizing EnSCs in vitro. We applied this latter technique for the first time on proliferative endometrial biopsies obtained during ovarian stimulation for in-cycle outcome prediction, in an attempt to overcome inter-cycle variability.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RNA-sequencing was performed for 18 individual whole-tissue endometrial biopsies on an Illumina HiSeq1500 machine. DGE was analysed three times using different approaches (DESeq2, EdgeR and the Wilcoxon rank-sum test, all in R). EnSC isolation and IVD was performed (for 2 and 4 days) for a subset of nine samples, after which media from undifferentiated and decidualized cultures were harvested, stored at -80°C and later assayed for 45 cytokines using a multiplex suspension bead immunoassay. The analysis was performed by partial least squares regression modelling.

MAIN RESULTS AND THE ROLE OF CHANCE

After correction for multiple hypothesis testing, DGE analysis revealed no significant differences between endometrial samples from patients who had a live birth and those with an implantation failure following fresh ET. However secretome analysis after EnSC isolation and culture, showed two distinct clusters that clearly corresponded to the two clinical groups. Upon IVD, the secretome profiles shifted from that of undifferentiated cells but the difference between the two clinical groups remained yet were muted, suggesting convergence of cytokine profiles after decidualization.

LIMITATIONS, REASONS FOR CAUTION

Caution is warranted due to the limited sample size of the study and the in vitro nature of the EnSC experiment. Validation on a larger scale is necessary, however, hard to fulfil given the very limited availability of in-cycle proliferative endometrial biopsies outside a RCT setting.

WIDER IMPLICATIONS OF THE FINDINGS

These data support the hypothesis that the endometrium should be assessed not only during the WOI and that certain endometrial dysfunctionalities can probably be detected early in a cycle by making use of the proliferative phase. This insight opens new horizons for the development of endometrial tests, whether diagnostic or predictive of IVF/ICSI treatment outcome.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Fonds Wetenschappelijk Onderzoek (FWO, Flanders, Belgium, 11M9415N, 1 524 417N), Wetenschappelijk Fonds Willy Gepts (WFWG G160, Universitair Ziekenhuis Brussel, Belgium) and the National Medicine Research Council (NMRC/CG/M003/2017, Singapore). There are no conflicts of interests.

TRIAL REGISTRATION NUMBER

NCT02061228.

A systematic review of clinical efficacy of frozen-thawed embryos and fresh embryos in in-vitro fertilization cycles

BACKGROUND

Frozen-thawed embryo (FTE) and fresh embryo (FE) transfer are two common strategies in vitro fertilization (IVF), while the results and findings still vary among studies.

METHODS

We searched multiple databases for relevant studies comparing the clinical effects of FTE and FE. Meta-analyses were conducted with Review Manager 5.0 to assess the efficacy among included articles. We also analyzed the risk of bias for the reports.

RESULTS

Nine studies eventually met the inclusion criteria from 2010 to 2018, and 11396 patients were included. The meta-analyses indicated no significant difference in biochemical pregnancy, clinical pregnancy and ongoing pregnancy rates. Meanwhile, the implantation rate and live birth rate in frozen-thawed embryos were much higher than those of fresh embryo. The birth weight in the frozen-thawed ET group was greater than that of the FE group, and the low birth weight rate in FTE was lower than FE group.

CONCLUSION

Our findings suggested a trend toward favouring frozen-thawed FTE might be a preferred transfer strategy for patients with IVF.

Endometrial Receptivity Analysis (ERA): data versus opinions

This article summarises and contextualises the accumulated basic and clinical data on the ERA test and addresses specific comments and opinions presented by the opponent as part of an invited debate. Progress in medicine depends on new technologies and concepts that translate to practice to solve long-standing problems. In a key example, combining RNA sequencing data (transcriptomics) with artificial intelligence (AI) led to a clinical revolution in personalising disease diagnosis and fostered the concept of precision medicine. The reproductive field is no exception. Translation of endometrial transcriptomics to the clinic yielded an objective definition of the limited time period during which the maternal endometrium is receptive to an embryo, known as the window of implantation (WOI). The WOI is induced by the presence of exogenous and/or endogenous progesterone (P) after proper oestradiol (E2) priming. The window lasts 30-36 hours and, depending on the patient, occurs between LH + 6 and LH + 9 in natural cycles or between P + 4 and P + 7 in hormonal replacement therapy (HRT) cycles. In approximately 30% of IVF cycles in which embryo transfer is performed blindly, the WOI is displaced and embryo-endometrial synchrony is not achieved. Extending this application of endometrial transcriptomics, the endometrial receptivity analysis (ERA) test couples next-generation sequencing (NGS) to a computational predictor to identify transcriptomic signatures for each endometrial stage: proliferative (PRO), pre-receptive (PRE), receptive (R) and post-receptive (POST). In this way, personalised embryo transfer (pET) may be possible by synchronising embryo transfer with each patient's WOI. Data are the only way to confront arguments sustained in opinions and/or misleading concepts; it is up to the reader to make their own conclusions regarding its clinical utility.

Placenta accreta spectrum-a catastrophic situation in obstetrics

Placenta accreta is a significant obstetric complication in which the placenta is completely or focally adherent to the myometrium. The worldwide incidence of placenta accreta spectrum (PAS) is increasing day by day, mostly due to the increasing trends in cesarean section rates. The accurate and timely diagnosis of placenta accreta is important to improve the feto-maternal outcome. Although standard ultrasound is a reliable and primary tool for the diagnosis of placenta accreta, the absence of ultrasound findings does not preclude the diagnosis of placenta accreta. Therefore, clinical evaluation of risk factors is equally essential for the prediction of abnormal placental invasion. Pregnant women with a high impression or established diagnosis of placenta accreta should be managed by a multidisciplinary team in a specialist center. Traditionally, PAS has been managed by an emergency obstetric hysterectomy. Previously, few studies suggested a satisfactory success rate of conservative management in well-chosen cases, whereas few studies recommended delayed hysterectomy to reduce the amount of bleeding. The continuously increasing trends of PAS and the challenges for its routine management are the main motives behind this literature review.

Time from oocyte retrieval to frozen embryo transfer in the natural cycle does not impact reproductive or neonatal outcomes

OBJECTIVE

To determine if the time from oocyte retrieval to frozen embryo transfer (FET) in the natural cycle affects reproductive or neonatal outcomes.

DESIGN

Retrospective cohort.

SETTING

Not applicable.

PATIENT(S)

Five hundred and seventy-six consecutive freeze-all cycles from January 2011 to December 2018 followed by natural cycle FET of a single blastocyst.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Primary outcome of live birth; secondary outcomes of preterm delivery (24-37 weeks) and small for gestational age (SGA) with a multivariable logistic regression performed with adjustment for age, infertility diagnosis, ovulatory trigger type, and preimplantation genetic testing (PGT).

RESULT(S)

Before adjustment for confounding, we found a statistically significantly different live-birth rate (57.7% vs. 48.6%) for natural cycle FET occurring in the first versus second menstrual cycle, respectively. In a multivariate analysis, performing a natural cycle FET of a single blastocyst in the second compared with the first menstrual cycle did not statistically significantly impact the odds of live-birth rate. After adjustment for age, diagnosis, and ovulatory trigger type, only PGT was associated with statistically significantly increased odds of live birth compared with no PGT. There were no differences in the incidence of SGA (male, 6.6% vs. 2.3%; female, 9.8% vs. 11.1%) or preterm delivery (1.6% vs. 5.6%) between both groups.

CONCLUSION(S)

Performing a natural cycle FET of a single blastocyst in the second compared with the first menstrual cycle after ovarian stimulation did not statistically significantly impact the odds of live birth or neonatal outcomes.

The clinical outcomes of fresh versus frozen embryos transfer in women ≥40 years with poor ovarian response

Objective

To compare the clinical outcomes of fresh embryo transfers (ETs) and frozen-thawed embryo transfers (FETs) after a freeze-all cycle in women ≥40 years old with poor ovarian response (POR).

Methods

We performed a single-center, retrospective, case-control study of patients who underwent in vitro fertilization between January 2014 and June 2019. We included a total of 192 patients aged 40 years or older from whom 3 or fewer oocytes had been retrieved and who were receiving cleavage-stage ET in this study. Of these patients, 101 and 91 patients underwent fresh ET and FET, respectively. The primary outcome was the live birth rate (LBR) after the first ET. Logistic regression analysis was used to compare the IVF outcomes and neonatal characteristics between the fresh ET and FET groups, adjusting for maternal age, body mass index, luteinizing hormone, and the number of good quality embryos transferred.

Results

The mean maternal ages and number of oocytes retrieved (43.2 years and 2.3 in both groups, P=0.902 and P=0.927, respectively) were similar in the fresh ET and FET groups. No significant difference was observed between the LBRs of the fresh ET and FET groups (adjusted odds ratio, 1.28; 95% confidence interval, 0.29–5.70). The clinical pregnancy and miscarriage rates, and neonatal characteristics (birth weights and premature infant rates) were similar between the 2 groups.

Conclusions

FET after the freeze-all strategy had no beneficial impact on the clinical outcomes of women ≥40 years with POR.

Description of the Follicular Fluid Cytokine and Hormone Profiles in Human Physiological Natural Cycles

PURPOSE

Exogenous gonadotrophins administration during in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycles could significantly alter the endogenous follicular regulation system and could influence oocyte quality. The analysis of the follicular fluid (FF) cytokine and hormone profiles in physiological natural cycles is crucial to appreciate the role of FF milieu on follicle development. So far, the FF cytokine profile has been analyzed only in controlled ovarian stimulation cycles and in modified natural cycles. Our study defines, in physiological natural cycles, the cytokine and hormone profiles of individual FF aspirated from antral follicles.

METHODS

A total of 203 FFs obtained from 83 women with regular menstrual cycles undergoing ovarian tissue cryopreservation were analyzed: 115 FFs from Group 1 (10 to 29 years of age) and 88 FFs from Group 2 (30 to 40 years of age). In individual FF, 27 cytokines were measured with xMAP technology, and progesterone, estrone, estradiol, testosterone, androstenedione concentrations were determined by liquid chromatography-tandem mass spectrometry.

RESULTS

FF hormone profiles were not different in follicular and luteal phase, suggesting that FF hormones are regulated independently of the endogenous gonadotrophins-possibly because 74% of the punctured follicles, which were ≤6 mm, did not require cyclic pituitary function. The follicle size was influenced not only by the FF cytokine profile but also by the FF hormone profile, both of which are dependent on age.

MAIN CONCLUSIONS

In physiological natural cycles, FF hormones seems to be regulated independently of the endogenous gonadotropins. Age influences FF hormone and cytokine profiles and the compelling relationship between FF hormones and FF cytokines could influence the follicle development.

Bushen Huoxue recipe attenuates early pregnancy loss via activating endometrial COX2-PGE2 angiogenic signaling in mice

BACKGROUND

During the fresh cycles of in vitro fertilization and embryo transfer, a disturbance in the reproductive endocrine environment following controlled ovarian hyperstimulation (COH) is closely related to compromised endometrial receptivity. This is a major disadvantage for women during pregnancy. Based on the theory of traditional Chinese medicine, Bushen Huoxue recipe (BSHXR) has been indicated to facilitate embryo implantation.

METHODS

The COH model (Kunming breed) was induced by injecting mice with pregnant mare serum gonadotrophin (0.4 IU/g) and human chorionic gonadotropin (1 IU/g), followed by treatment with BSHXR at three different concentrations (5.7, 11.4, and 22.8 g/kg), Bushen recipe (BSR) (5.7 g/kg), and Huoxue recipe (HXR) (5.7 g/kg). After successful mating, the pregnancy rate and implantation sites were examined on embryo day 8 (ED8), and the weight ratio of endometrium was calculated on ED4 midnight. Serum estrogen, progesterone, and endometrial PGE2 levels were measured using enzyme-linked immunosorbent assay. The endometrial microvasculature was evaluated using CD31 immunostaining. The protein and mRNA levels of the angiogenic factors in the endometrium were evaluated using western blot, immunohistochemistry, and polymerase chain reaction.

RESULTS

In the COH group, the pregnancy rate and implantation sites were significantly decreased, and abnormal serum hormone levels and impaired endometrial vascular development were observed. After BSHXR treatment, the supraphysiological serum progesterone level in COH mice was restored to normalcy. Moreover, the abnormal expression of the endometrial pro-angiogenic factors, including HIF1α, COX2-PGE2 pathway, and the down-stream factors, namely, MMP2, MMP9, TIMP2, and FGF2 after subjecting mice to COH was significantly improved after BSHXR treatment.

CONCLUSION

BSHXR could improve embryo implantation by regulating hormonal balance and modulating endometrial angiogenesis in mice, without inducing any side effects in normal pregnancy.

Effect of Endometrium Thickness on Clinical Outcomes in Luteal Phase Short-Acting GnRH-a Long Protocol and GnRH-Ant Protocol

OBJECTIVE

To investigate the factors that influence luteal phase short-acting gonadotropin-releasing hormone agonist (GnRH-a) long protocol and GnRH-antagonist (GnRH-ant) protocol on pregnancy outcome and quantify the influence. About the statistical analysis, it is not correct for the number of gravidities.

METHODS

Infertile patients (n = 4,631) with fresh in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) and embryo transfer were divided into GnRH-a long protocol (n =3,104) and GnRH-ant (n =1,527) protocol groups and subgroups G1 (EMT ≤7mm), G2 (7 mm <EMT ≤10 mm), and G3 (EMT >10 mm) according to EMT on the trigger day. The data were analyzed.

RESULTS

The GnRH-ant and the GnRH-a long protocols had comparable clinical outcomes in the clinical pregnancy, live birth, and miscarriage rate after propensity score matching. In the medium endometrial thickness of 7-10 mm, the clinical pregnancy rate (61.81 vs 55.58%, P < 0.05) and miscarriage rate (19.43 vs 12.83%, P < 0.05) of the GnRH-ant regime were significantly higher than those of the GnRH-a regime. The EMT threshold for clinical pregnancy rate in the GnRH-ant group was 12 mm, with the maximal clinical pregnancy rate of less than 75% and the maximal live birth rate of 70%. In the GnRH-a long protocol, the optimal range of EMT was >10 mm for the clinical pregnancy rate and >9.5 mm for the live birth rate for favorable clinical outcomes, and the clinical pregnancy and live birth rates increased linearly with increase of EMT. In the GnRH-ant protocol, the EMT thresholds were 9-6 mm for the clinical pregnancy rate and 9.5-15.5 mm for the live birth rate.

CONCLUSIONS

The GnRH-ant protocol has better clinical pregnancy outcomes when the endometrial thickness is in the medium thickness range of 7-10 mm. The optimal threshold interval for better clinical pregnancy outcomes of the GnRH-ant protocol is significantly narrower than that of the GnRH-a protocol. When the endometrial thickness exceeds 12 mm, the clinical pregnancy rate and live birth rate of the GnRH-ant protocol show a significant downward trend, probably indicating some negative effects of GnRH-ant on the endometrial receptivity to cause a decrease of the clinical pregnancy rate and live birth rate if the endometrial thickness exceeds 12 mm.

Cargo small non-coding RNAs of extracellular vesicles isolated from uterine fluid associate with endometrial receptivity and implantation success

OBJECTIVE

To optimize a method of isolating extracellular vesicles (EVs) from uterine fluid and to characterize small non-coding RNAs (sncRNAs) from the EVs, with the goal of identifying novel receptivity-associated biomarkers.

DESIGN

Longitudinal study comparing sncRNA expression profiles from endometrial EVs.

SETTING

University-affiliated, hospital-based fertility clinic.

PATIENT(S)

Healthy volunteers with no history of infertility (Group A) and women receiving controlled ovarian stimulation (COS)-in vitro fertilization treatment (Group B).

INTERVENTIONS(S)

In Group A, EVs were isolated from uterine fluid obtained on luteinizing hormone (LH)+2 and LH+7 in one natural menstrual cycle. In Group B, EVs were isolated from uterine fluid obtained on human chorionic gonadotropin (hCG)+2 and hCG+7 in one COS cycle. RNAs extracted from EVs were profiled using next-generation sequencing.

MAIN OUTCOME MEASURE(S)

Differential EV-sncRNAs between LH+2 and LH+7 (Group A), between hCG+2 and hCG+7 (Group B), and between pregnant and nonpregnant in vitro fertilization cycles (Group B).

RESULT(S)

Ultracentrifugation was validated as the most efficient method to isolate EVs from uterine fluid. We identified 12 endometrial EV-sncRNAs (11 microRNAs and 1 piwi-interacting RNA) as receptivity-associated transcripts conserved in both natural and COS cycles. These sncRNAs were associated strongly with biological functions related to immune response, extracellular matrix, and cell junction. Within COS cycles, we also identified a group of EV-sncRNAs that exhibited differential expression in patients who conceived versus those who did not, with hsa-miR-362-3p most robustly overexpressed in the nonpregnant patients.

CONCLUSION(S)

This study is the first to profile comprehensively sncRNAs in endometrial EVs from uterine fluid and identify sncRNA biomarkers of endometrial receptivity and implantation success.

The freeze-all strategy after IVF: which indications?

The freeze-all strategy is gaining popularity worldwide as an alternative to the conventional fresh embryo transfer. It consists of cryopreservation of the entire embryo cohort and the embryo transfer in a subsequent cycle that takes place separately from ovarian stimulation. The freeze-all strategy was initially a 'rescue' strategy for women at high risk of ovarian hyperstimulation syndrome; however, this approach has been extended to other indications as a scheduled strategy to improve implantation rates. This assumes that ovarian stimulation can alter endometrial receptivity in fresh cycles owing to the effect of supraphysiological levels of steroids on endometrial maturation. The procedure, however, has not been associated with increased live birth rates in all infertile couples, and concerns have been raised about the occurrence of several adverse perinatal outcomes. It is, therefore, crucial to identify in which subgroups of patients a freeze-all strategy could be beneficial. The aim of this review is to summarize current scientific research in this field to highlight potential indications for this strategy and to guide clinicians in their daily practice.

A freeze-all strategy does not increase live birth rates in women of advanced reproductive age

RESEARCH QUESTION

Does a freeze-all strategy improve live birth rates in women of different age groups?

DESIGN

Retrospective cohort study of 1882 first embryo transfer cycles, performed between January 2013 and December 2015. Reproductive outcomes between fresh (FRESH) or frozen (FROZEN) embryo transfers were compared in patients stratified by age: < 35, between 35 and 38, or > 38 years. Student's t test for independent samples and χ² analyses were used as needed. A multivariable logistic regression analysis was performed adjusting for age, triggering drug, number of retrieved oocytes, number of transferred embryos, and percentage of top-quality embryos.

MAIN RESULTS AND THE ROLE OF CHANCE

Live birth rates (LBR) were significantly higher for FROZEN in the < 35 years group (43.7% vs 24%; p < 0.001). In both the 35-38 and > 38 years groups, LBR for FROZEN vs FRESH were not statistically different (30.9% in the FROZEN group vs 29.3% in the FRESH group, p = 0.70, and 19.8% in the FROZEN group vs 12.7% in the FRESH group, p = 0.07, respectively). The multivariate analysis found a significantly positive effect of performing FROZEN on LBR in the younger group (OR 2.46, 95% CI 1.31-4.62; p = 0.005) but had no impact in women between 35 and 38 years (OR 1.01, 95% CI 0.55-1.83; p = 0.98) or older (OR 0.96, 95% CI 0.43-2.13; p = 0.92).

CONCLUSIONS

Performing a freeze-all strategy seems to result in better reproductive outcomes when compared with a fresh ET in women under 35 years, with no significant impact on older women.

Uterine Gpr83 mRNA is highly expressed during early pregnancy and GPR83 mediates the actions of PEN in endometrial and non-endometrial cells

OBJECTIVE

To characterize the expression and signaling of uterine GPR83 in vivo in the nonpregnant and pregnant mouse and in vitro in human endometrial and nonendometrial cells.

DESIGN

Controlled laboratory study.

SETTING

Not applicable.

PATIENTS

Not applicable.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Expression of uterine Gpr83 was determined by quantitative polymerase chain reaction throughout the estrous cycle and during early pregnancy in ovarian-stimulated and non-ovarian-stimulated mice and pregnant and pseudopregnant mice. Expression was also determined in ovariectomized mice after the administration of oil, E2, P4, or E2 + P4 and in stromal cells following 6 days of in vitro decidualization. GPR83 signaling was studied in human endometrial and embryonic kidney cell lines. Cells were treated by PEN, a GPR83 ligand, and PEN-induced extracellular signal-regulated kinase (ERK) phosphorylation was assayed under conditions that blocked Gα_q/11 and/or β-arrestin signaling.

RESULTS

Uterine Gpr83 is expressed throughout the estrous cycle and during early pregnancy; expression increases dramatically at the time of uterine receptivity, embryo implantation, and stromal cell decidualization. In the ovariectomized mouse, hormone add-back reveals that Gpr83 expression is highly responsive to the combined treatment of E2 and P4, and studies in the ovarian-stimulated mouse show that expression is also very sensitive to changes in E2 and P4 and is therefore tightly regulated by E2 and P4. At the implantation site, expression is elevated up to D6 of pregnancy and then declines rapidly on D7 and D8, suggesting that if there is any involvement in decidualization, it is likely associated with primary but not secondary stromal cell decidualization. This premise was supported by the observation that stromal cell decidualization in vitro progresses with a decline in Gpr83 expression. In ERα/PR-expressing endometrial Ishikawa cells, GPR83 mediates PEN signals in a Gα_q/11-dependent manner, and studies conducted in HEK 293 cells lacking β-arrestin revealed that GPR83 also signals via a β-arrestin-dependent manner. When signaling by either one or both pathways is downregulated, cells exhibit a major reduction in responsiveness to PEN treatment, demonstrating that signaling by both pathways is significant.

CONCLUSION

We hypothesize that PEN/GPR83 signaling regulates uterine receptivity, embryo implantation, and primary stromal cell decidualization by coupling to Gα_q/11- and β-arrestin-dependent pathways.

A comparison of IVF outcomes transferring a single ideal blastocyst in women with polycystic ovary syndrome and normal ovulatory controls

PURPOSE

To assess the effects PCOS on live birth rates when transferring a single fresh ideal blastocyst.

METHODS

A retrospective cohort study performed at the university-affiliated reproductive center. Women with PCOS and a control group of normal ovulatory women who underwent their first fresh embryo transfer with single ideal grade blastocyst were included in the study. Demographic, stimulation information and pregnancy outcomes were collected and analysed. The primary outcome was live birth rates, and secondary outcomes included pregnancy and clinical pregnancy rates.

RESULTS

71 Women with PCOS and 272 normal ovulatory controls underwent their first embryo transfer and met the inclusion and exclusion criteria. PCOS patient were younger (31.0 ± 3.7 vs. 33.1 ± 3.2, p = 0.0001), with higher AFC (40.0 ± 9.3 vs. 13.3 ± 4.6, p = 0.0001), required lower dose of gonadotropins to stimulate (1198 ± 786 vs. 1891 ± 1224, p = 0.0001), and had higher serum testosterone levels (2.3 ± 0.7 vs. 1.1 ± 0.3, p = 0.0001). No significant difference was found between the two groups regarding the number of previous pregnancies, the number of previous full-term pregnancies, the level of basal serum FSH, estradiol level at triggering and the BMI. When compared by Chi squared testing pregnancy rates, clinical pregnancy rates and live birth rates did not differ. However, when controlling (with multivariate stepwise logistic regression) for confounders, live birth rates were lower among the women with PCOS (p = 0.035, CI: 0.18-0.92).

CONCLUSION

After controlling for confounders, when transferring a fresh single ideal blastocyst, live birth rates were lower among the women with PCOS than normal ovulatory controls.

Impact of elective frozen vs. fresh embryo transfer strategies on cumulative live birth: Do deleterious effects still exist in normal & hyper responders?

Background

Is freeze-all strategy effective in terms of cumulative live birth rates (CLBRs) in all patients?

Methods

This retrospective single-center study analyzed the CLBRs of 2523 patients undergoing fresh or electively frozen blastocyst transfer cycles. In 1047, cycles, the fresh embryo transfer (ET) strategy was applied for the 1^st ET, whereas electively frozen ET (e-FET) was performed in 1476 cycles. Female age ≤ 37 and blastocysts frozen via vitrification were included. The patients in each arm were further stratified into four subgroups according to the number of oocytes retrieved as follows: Group A: 1–5, group B: 6–10, group C: 11–15 and group D: 16–25 oocytes retrieved. The primary endpoint was the CLBR. The secondary endpoints were the ovarian hyperstimulation syndrome (OHSS) rate and the live birth rates (LBRs) following fresh ETs and e-FETs for the first transfers.

Result(s)

The CLBR was similar between the fresh ET and e-FET arms in group A (35/76 (46.1%) vs 29/67 (43.3%), p = 0.74) and group B (165/275 (60%) vs 216/324 (66.7%), p = 0.091), whereas significantly higher rates were detected in favor of the e-FET arm within group C (328/460 (71.3%) vs 201/348 (57.8%), p<0.001) and group D (227/348 (65.2%), vs 446/625 (71.5%), p<0.001). The OHSS rate was also found to be higher in the fresh ET arm among group C (12/348 (3.4%) vs 0/460 (0%), p<0.001) and group D (38/348 (10.9%) vs 3/625 (0.5%), p<0.001) patients than e-FET arm. Perinatal and obstetrical outcomes were nonsignificantly different between fresh and e-FET arms. However, the birth weights were significantly lower for fresh ET, 3064 versus 3201 g for singletons (p<0.001)

Conclusion

Compared with a fresh-transfer strategy, the e-FET strategy resulted in a higher CLBR among patients with >10 oocytes retrieved during stimulated cycles.

Does a hyperechogenic endometrial mass in the uterus during controlled ovarian stimulation affect assisted reproductive technology cycle outcomes?

OBJECTIVES

Healthy embryos and endometrial receptivity are keys to the success of in-vitro fertilization and embryo transfer (IVF-ET). Abnormal transvaginal ultrasonography (TVU) findings in the endometrium are a concern during assisted reproductive technology (ART) treatments. Observation of a hyperechogenic endometrial mass (HEM) during controlled ovarian stimulation (COS) in an IVF or intracytoplasmic sperm injection (ICSI) cycle is a dilemma. Here we investigated whether an HEM would affect ART cycle outcomes.

STUDY DESIGN

We analyzed all data from patients who underwent IVF or ICSI treatment cycles from January 1, 2009 to December 31, 2016 at our institution. Patients diagnosed with an HEM were included. Each woman was matched with two control subjects of similar age (± 1 year), in terms of the number of cycles, type of infertility (primary or secondary), protocol used for COS, but with no HEM identified by TVU. Baseline characteristics, COS response, and pregnancy outcomes after ET were compared.

RESULTS

In all, 1088 patients were diagnosed with an HEM. Of these, 426 met the inclusion criteria and were matched with 852 controls. Baseline characteristics showed no significant differences between the groups. The peak endometrial thickness was significantly greater in the experimental group than in the control group (1.15 ± 0.18 cm vs. 1.08 ± 0.21 cm, p < 0.001). The live birth rates were 43.7% vs 46.2% in the experimental and control groups, respectively. There were no significant between-group differences in the rates of biochemical or clinical pregnancy or abortions at any stage.

CONCLUSIONS

Newly diagnosed HEMs < 18 mm in diameter monitored by TVU did not impair the outcomes of ART following COS in this study. If other conditions are suitable, completion of ART cycles should be the appropriate approach in such cases.

KEY MESSAGE

Newly diagnosed hyperechogenic endometrial masses measuring <18 mm in diameter monitored by TVU during COS did not adversely affect the outcomes of these IVF/ICSI-ET cycles.

Frozen IVF Cycles to Circumvent the Hormonal Storm on Endometrium

Controlled ovarian hyperstimulation (COH) determines an anticipation of endometrial maturation and a premature occurrence of the implantation window, as shown by histological, histochemical, and molecular studies and indirectly by clinical trials. There is growing agreement that in patients hyper-responding to COH and in those undergoing transfer at the blastocyst stage, deferring the transfer in a subsequent frozen cycle could increase pregnancy outcomes. For blastocysts, implantation after a fresh transfer may be limited as the implantation window is already closed while, in hyper-responders to COH, the anticipation magnitude could be more marked thus hampering implantation also for cleavage-stage embryos. Research should focus in depth on pregnancy outcomes and on the most suitable modality to prepare the endometrium for frozen transfers.

The Influence of Delayed Blastocyst Development on the Outcome of Frozen-Thawed Transfer of Euploid and Untested Embryos

Objective

The primary objective is to compare live birth rates (LBRs) following frozen embryo transfer (FET) of euploid day 5 with day 6 blastocysts. We also compared LBRs following FET of untested blastocysts vitrified on day 5 and day 6 in self-oocyte and ovum donation (OD) cycles.

Design

This was a retrospective observational study.

Setting

Nova IVF Fertility, Ahmedabad.

Materials and Methods

Ninety-seven FET using self-oocytes following preimplantation genetic testing A (PGT-A), 464 FET following OD, and 907 FET using self-oocytes without PGT-A testing between January 2016 and December 2017 were included in this study.

Main Outcome Measures

LBR following FET in day 5 versus day 6 blastocysts in euploid embryos using self-oocytes and in untested embryos using both self and donor oocytes.

Results

In PGT-A cycles, no statistically significant difference was observed in LBRs following transfer of euploid blastocysts developed on day 5 or day 6 (D5: 53%; D6:40%, P = 0.83). However, the LBRs with day 5 blastocysts were higher compared with day 6 group in untested group using both self and donor oocytes (self D5: 52.7%; D6: 38.2%; P = 0.001 and OD D5: 44.7%; D6: 29.8%; P = 0.001). Miscarriage rates were comparable in both the groups.

Conclusions

The present study demonstrated comparable pregnancy outcomes following FET of euploid embryos vitrified on day 5 and day 6. However, higher LBRs were reported in day 5 group in untested embryos.

Placental pathology in live births conceived with in vitro fertilization after fresh and frozen embryo transfer

BACKGROUND

The availability and use of frozen embryos after ovarian hyperstimulation for assisted reproduction has increased with improvement in vitrification techniques and the rise of preimplantation genetic testing. However, there are conflicting data regarding whether obstetric outcomes differ between fresh and frozen embryo transfer cycles.

OBJECTIVE

To compare placental pathology from live births arising from fresh and frozen embryo transfer cycles.

MATERIALS AND METHODS

A cohort of 1140 live births with placental pathology arising from autologous in vitro fertilization cycles with fresh or frozen programmed transfer performed at MGH Fertility Center between 2004 and 2017 was retrospectively reviewed. An experienced placental pathologist categorized the reported placental pathology as anatomic, infectious, inflammatory, or vascular/thrombotic. Our primary outcomes were differences in these placental pathologies between the 2 groups. Patient demographic, cycle, and birth outcomes were compared with the use of χ² tests, Student t test, or nonparametric tests, as appropriate. Multivariate logistic regression models were used to compare placental pathology between the fresh and frozen transfer groups.

RESULTS

Of the 1140 cycles included in our analysis, 929 arose from fresh embryo transfers (81.3%) and 211 arose from programmed frozen embryo transfers (18.5%). For both transfer types, the average age of the women at time of treatment was 35 years; mean body mass indices were within the normal range (23.6 kg/m² for fresh transfers and 23.2 kg/m² for frozen transfers, P = .26), and mean day 3 follicle-stimulating hormone values were 7.1 and 7.0 IU/L (P = .44), respectively. Deliveries occurred on average at 37.5 and 38.0 weeks' gestational age (P = .04) in the fresh versus frozen transfer group, with similar rates of obstetric complications. However, frozen transfers were more likely to be associated with marginal cord insertion (adjusted odds ratio, 1.87; confidence interval, 1.21, 2.91; P = .01), accessory lobe formation (adjusted odds ratio, 2.96; confidence interval, 1.12, 7.79; P = 0.03), subchorionic thrombi (adjusted odds ratio, 3.72; confidence interval, 1.80, 7.71; P < .001), and fetal vascular malperfusion characteristics with cord anomalies (adjusted odds ratio, 2.34; confidence interval, 1.22, 4.46; P = .01). These trends persisted when we analyzed day 5 transfers alone, and single frozen embryo transfers remained associated with increased rates of subchorionic thrombi compared to single fresh embryo transfers.

CONCLUSION

Pregnancies arising from frozen embryo transfers demonstrated more anatomic and vascular placental pathology than those from fresh transfers in our cohort of patients, despite similar maternal outcomes. More research is needed to explore how these differences in pathology may influence obstetric and perinatal outcomes.

Dynamic Expression of Interleukin-33 and ST2 in the Mouse Reproductive Tract Is Influenced by Superovulation

Interleukin-33 (IL-33) is an IL-1 family cytokine with pleiotropic effects on diverse cell types. Dysregulated IL-33 signaling has been implicated in pregnancy-related disorders, including preeclampsia and recurrent pregnancy loss, and in ovarian function in women undergoing controlled ovarian stimulation for in vitro fertilization. To date, expression of IL-33 and its receptor subunit, ST2, in the female reproductive tract remains poorly characterized. We identify IL-33-expressing oocytes surrounded by ST2-expressing granulosa cells at all stages of follicular development, in addition to IL-33⁺ and ST2⁺ non-endothelial cells in the ovarian stroma and theca layer in ovaries from adult mice. These expression patterns are similar in estrus- and diestrus-stage adults and in pubescent mice, suggesting a role for IL-33 signaling in ovarian function throughout development and in the estrous cycle. In the uterus, we find expression of IL-33 and ST2 in glandular and luminal epithelia during estrus and at the initiation of pregnancy. Uterine IL-33 expression was modulated by the estrous cycle and was reduced in pubescent females. Last, superovulation increases transcripts for IL-33 and the soluble form of ST2 (sST2) in ovaries, and for IL-33 in uteri. Collectively, our findings lay the foundation for studies identifying cell type-specific requirements for IL-33/ST2 signaling in the establishment and maintenance of mouse pregnancy.