Endometrial pinopodes indicate a shift in the window of receptivity in IVF cycles

A comparative analysis of the clinical pregnancy and perinatal outcomes between oocyte vitrification and embryo vitrification based on the propensity score matching method

PURPOSE

This study investigated the safety and effectiveness of oocyte vitrification by comparing the clinical pregnancy and perinatal outcomes between transfer cycles of vitrified oocytes and those of vitrified embryos.

METHODS

A retrospective cohort study was conducted to analyze the clinical data of patients who underwent cleavage-stage embryo transfer at the Department of Reproductive Medicine between January 2011 and June 2021. Seventy-seven transfer cycles of fresh cleavage-stage embryos developed from vitrified-thawed oocytes (oocyte vitrification group) and 2170 transfer cycles of vitrified-thawed cleavage-stage embryos developed from fresh oocytes (embryo vitrification group) were included. Further, 293 cases were selected from the embryo vitrification group after applying propensity score matching at 1:4. The primary outcomes were miscarriage rate, live birth rate, and neonatal birth weight.

RESULTS

No statistically significant differences were observed in the baseline data, pregnancy, perinatal outcomes, or neonatal outcomes for either singleton or twin births between the two groups after matching. Backwards stepwise regression was used to analyze the length of gestation. The age of female participants (β =  - 0.410, 95% CI =  - 1.339 ~  - 0.620, P < 0.001) had a statistically significant effect.

CONCLUSION

Oocyte vitrification results in similar clinical pregnancy and perinatal outcomes as does embryo vitrification; hence, it is a relatively safe assisted reproductive technique.

Yueliang Yin Ameliorates Endometrial Receptivity in Mice with Embryo Implantation Failure by Reducing Pyroptosis and Activating BDNF/TrkB Pathway

SCOPE

Endometrial receptivity plays a vital role in embryonic implantation. Yueliang Yin is a marketed solid drink in China, also known as Bushen Cuyun Recipe (BCR), that is, assumed to have a therapeutic effect on infertility by improving endometrial receptivity. This study investigates the effects and mechanisms of BCR in protecting the endometrium.

METHODS AND RESULTS

Mice with mifepristone-induced embryo implantation failure that exhibited a decreased implantation sites number, thinner endometrium, reduced endometrial glands number, and poor pinopode expression levels are treated with BCR, and these mentioned conditions significantly improves afterward. Molecular docking shows that the main active components kaempferol, quercetin, and hesperetin of BCR stably bound to gasdermin D (GSDMD). Experimental results demonstrate that levels of GSDMD, cleaved caspase-1 and leucine-rich repeat, and pyrin domain-containing 3 and IL-1β levels in model mice are significantly decreased and expressions of brain-derived neurotrophic factor (BDNF) and tyrosine protein kinase B (TrkB) expression levels are significantly elevated after BCR treatments, and that the DNA damage is significantly reversed in BCR-treated mice.

CONCLUSIONS

BCR is potent and effective in ameliorating endometrial receptivity. The potential mechanisms of BCR on endometrial receptivity may mediate by activating BDNF/TrkB pathway activation and protecting endometrial cells' protection against pyroptosis.

Embryo Cryopreservation in a Patient with Sickle Cell Disease Utilizing Letrozole and Enoxaparin: A Case Report

PURPOSE

To describe a patient with sickle cell disease, a prothrombotic disorder, who underwent successful embryo cryopreservation for the purposes of fertility preservation prior to hematopoietic stem cell transplant.

METHODS

To report a successful case of gonadotropin stimulation and embryo cryopreservation using the aromatase inhibitor letrozole to maintain low serum estradiol to minimize thrombotic risk in a patient with sickle cell disease (SCD) and history of retinal artery thrombosis planning hematopoietic stem cell transplant (HSCT). The patient was given letrozole (5 mg daily) as well as prophylactic enoxaparin while undergoing gonadotropin stimulation with an antagonist protocol to preserve fertility prior to HSCT. After the oocyte retrieval, letrozole was continued for one additional week.

RESULTS

The patient's peak serum estradiol concentration was 172 pg/mL during gonadotropin stimulation. Ten mature oocytes were retrieved and a total of 10 blastocysts were cryopreserved. The patient required pain medication and intravenous fluids after oocyte retrieval due to pain but had significant improvement at the scheduled post-operative day one follow-up. No embolic events occurred during stimulation or 6 months thereafter.

CONCLUSION

The utilization of definitive treatment for SCD with stem cell transplant is increasing. We successfully used letrozole to maintain low serum estradiol during gonadotropin stimulation along with prophylactic enoxaparin in a patient with SCD to minimize her risk of thrombosis. This approach will allow patients planning definitive treatment with stem cell transplant the opportunity to preserve their fertility safely.

Is there an optimal window of time for transferring single frozen-thawed euploid blastocysts? A cohort study of 1170 embryo transfers

STUDY QUESTION

Is there an optimal window of time when the transfer of single frozen-thawed euploid blastocysts is associated with a maximal live birth rate (LBR)?

SUMMARY ANSWER

Performing a single frozen-thawed euploid blastocyst transfer at 160 ± 4 h post-hCG trigger in modified-natural frozen-thawed embryo transfer (FET) cycles was independently associated with a higher LBR as compared to transfers outside this window; however, in natural FET cycles, LBRs were comparable across a wider range of time intervals.

WHAT IS KNOWN ALREADY

There is compelling evidence for maintaining embryo-endometrial synchrony to optimize clinical outcomes following FETs, which could potentially be achieved by matching the transfer time of an embryo post-ovulation to its developmental age post-oocyte retrieval. For modified-natural cycles, ovulation is widely accepted to occur ∼40 h following the hCG trigger, whilst ovulation following spontaneous LH surge onset is thought to vary from 24 to 56 h.

STUDY DESIGN, SIZE, DURATION

This is a multicentered retrospective cohort study analyzing 1170 single frozen-thawed euploid blastocyst transfers following trophectoderm biopsy and preimplantation genetic testing (PGT) between May 2015 and February 2019. Limiting the analysis to single euploid embryo transfers allowed for a more accurate estimation of the endometrial synchrony factor by controlling for the developmental stage of the embryo (full blastocyst or more advanced) and its genetic composition. LBR per FET was the primary outcome measure.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients underwent natural or gonadotrophin-induced preparation of the endometrium, with serial serum oestradiol, LH and progesterone measurements. Optimally timed transfers were predefined as those conducted 120 ± 4 h post-ovulation since biopsy and subsequent cryopreservation of full blastocysts which is usually performed at 116-124 h post-oocyte retrieval. This was considered the equivalent of 160 ± 4 h post-hCG trigger in modified-natural cycles (n = 253), as ovulation was assumed to occur ∼40 h after the hCG trigger. For natural cycles (n = 917), this was also considered to be, on average, 160 ± 4 h post the spontaneous LH surge. Thus, study groups were determined as those with optimal timing or not, and additional exploratory and subgroup analyses were performed, varying the time window in terms of onset and width, both overall and per endometrial preparation protocol. Statistical analysis was performed using the generalized estimating equations (GEE) framework to control for the clustered nature of the data while adjusting for potential confounders.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, LBRs were significantly higher when the transfer had been performed at 160 ± 4 h post-hCG trigger or LH surge onset compared to when it had been performed outside this window (44.7% vs 36.0%; P = 0.008). A multivariable regression GEE model including the cycle type (natural versus modified-natural), previtrification embryo quality (top versus good quality), embryo stage (fully hatched versus hatching or earlier blastocyst), vitrification day (D5 versus D6) and survival rate (>90% versus <90%) as covariates, confirmed that, overall, embryo transfers conducted 160 ± 4 h post-hCG trigger or LH surge onset (the assumed equivalent of 120 ± 4 h post-ovulation) were associated with a significantly higher LBR (relative risk (RR) 1.21, 95% CI 1.04-1.41). Subgroup exploratory analyses per endometrial preparation protocol demonstrated that these findings were primarily present in the modified-natural cycle group (RR 1.52, 95% CI 1.15-1.99), whilst the natural cycle group showed comparable LBRs across a wider range of time intervals. Moreover, the overall LBR for the natural group (36.8%; 95% CI 33.7-39.9%) was lower than that of the modified-natural group (41.3%; 95% CI 35.4-47.1%), suggesting that there likely remains a greater potential to further optimize the timing of natural cycle embryo transfers.

LIMITATIONS, REASONS FOR CAUTION

As with all retrospective studies, the presence of residual unknown bias cannot be excluded. Additionally, patients included in this study were a selected group who underwent PGT for specific reasons and hence the results obtained might not be directly applicable to the general population or embryos that have not undergone embryo biopsy. Furthermore, the criteria utilized to interpret hormonal data from natural cycles were specifically adopted for the present study and need to be validated in further studies.

WIDER IMPLICATIONS OF THE FINDINGS

The results of this study highlight the significance of embryo-endometrial synchrony for the optimization of frozen embryo transfer outcome. However, it also clearly supports that the implantation window is in most cases wide and the achievement of live birth is possible with relatively high success rates even outside the optimal window of 160 ± 4 h post-trigger for modified-natural cycles and across a range of time intervals for natural cycles. Additionally, this study suggests that implantation rates could be further optimized in natural cycles by improving methods of assessing embryo-endometrial synchrony.

STUDY FUNDING/COMPETING INTEREST(S)

C. V. is supported by a National Health and Medical Research Council Early Career Fellowship (GNT1147154). No other funding was received for this study and there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

The Combined Use of Medium- and Short-Chain Fatty Acids Improves the Pregnancy Outcomes of Sows by Enhancing Ovarian Steroidogenesis and Endometrial Receptivity

Fatty acids play important roles in maintaining ovarian steroidogenesis and endometrial receptivity. Porcine primary ovarian granulosa cells (PGCs) and endometrial epithelial cells (PEECs) were treated with or without medium- and short-chain fatty acids (MSFAs) for 24 h. The mRNA abundance of genes was detected by fluorescence quantitative PCR. The hormone levels in the PGCs supernatant and the rate of adhesion of porcine trophoblast cells (pTrs) to PEECs were measured. Sows were fed diets with or without MSFAs supplementation during early gestation. The fecal and vaginal microbiomes were identified using 16S sequencing. Reproductive performance was recorded at parturition. MSFAs increased the mRNA abundance of genes involved in steroidogenesis, luteinization in PGCs and endometrial receptivity in PEECs (p < 0.05). The estrogen level in the PGC supernatant and the rate of adhesion increased (p < 0.05). Dietary supplementation with MSFAs increased serum estrogen levels and the total number of live piglets per litter (p < 0.01). Moreover, MSFAs reduced the fecal Trueperella abundance and vaginal Escherichia-Shigella and Clostridium_sensu_stricto_1 abundance. These data revealed that MSFAs improved pregnancy outcomes in sows by enhancing ovarian steroidogenesis and endometrial receptivity while limiting the abundance of several intestinal and vaginal pathogens at early stages of pregnancy.

Plane of nutrition and FSH-induced superovulation affect the expression of steroid hormone receptors and growth factors in caruncular tissue of non-pregnant sheep

Implantation is a critical step in the establishment of pregnancy and an important part of embryo-maternal contact. Uterine receptivity can be affected by changes in body condition and the maternal endocrine milieu, including those caused by the use of exogenous gonadotropins in controlled ovarian hyperstimulation to induce the development of multiple follicles. This study demonstrates the effects of FSH-mediated ovarian hyperstimulation on the caruncles of ewes under various feeding regimes. Sheep were classified into 3 categories: control fed (CF), overfed (OF), or underfed (UF). In each group, animals were superovulated with FSH or injected with a saline solution (non-treated control). Uterine caruncles were collected at the early (d 5) and mid-luteal phase (d 10) of the estrous cycle. The transcript levels of steroid hormone receptors (ESR1, ESR2, PGR) and growth factors (IGF1, IGF2, VEGFA) were investigated and their expression localized by immunohistochemical staining. As for the main findings, day of the estrous cycle affected expression of ESR1, IGF1 and IGF2, but not of ESR2, PGR and VEGFA; both feeding and superovulation had modulatory effects, with feeding (UF/OF) stimulating expression of all genes studied, and superovulation altering expression of some genes, eg IGF1, PGR and ESR1 and ESR2, in CF animals. Similarly, feeding (UF/OF) altered responsiveness to superovulation for PGR on d 5 and ESR1/ESR2 on d 5 and/or 10. Our data emphasize possible effects of dietary and/or hormonal stimuli on uterine physiology, which may affect pregnancy outcomes by disrupting uterine functionality.

Meta-analysis of the embryo freezing transfer interval

BACKGROUND

The decision of whether frozen embryo transfer (FET) should be performed in the cycle immediately after OPU or at least one cycle later is controversial. FET could improve pregnancy rates in IVF; however, how much time is needed for the endometrium to return to optimal receptivity after ovarian stimulation is not known.

METHODS

Electronic search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials to identify studies providing data on the influence of the interval between embryo freezing (or OPU) and FET in FET cycles published between January 1, 2007, and February 1, 2020.

MAIN FINDINGS

Data analyzed indicated that in the immediate FET cycles, there was a trend to an increased biochemical pregnancy rate (RR = 1.08; CI = 1.00-1.18), whereas the clinical pregnancy rate was somewhat higher, but without reaching statistical significance (RR = 1.07; CI = 0.99-1.15). The live birth rate was similar in the two groups (RR = 1.05; CI = 0.95-1.15), as was the implantation rate (RR = 0.98; CI = 0.83-1.16). Stratifying by embryo stage or FET type (freeze-all or FET after failed fresh transfer) showed no differences.

CONCLUSION

Systematically delaying FET does not offer benefits to IVF outcomes. In addition, immediate transfer is associated with a nonsignificant trend to better clinical pregnancy rate and it also avoids the psychological effects of prolonging the stress on prospective parents.

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.

Pinopodes: Recent advancements, current perspectives, and future directions

Successful embryo implantation is a complex and highly regulated process involving precise synchronization between the fetal-derived trophoblast cells and maternal uterine luminal epithelium. Multiple endocrine-driven factors are important for controlling the timely receptivity of the uterus, and this complexity underscores implantation failure as a major cause of recurrent infertility associated with assisted reproductive technologies. One particular cellular structure often hypothesized to promote receptivity is the pinopode or uterodome - a hormonally regulated, large cellular protrusion on the uterine epithelial surface. Recent clinical studies associate pinopodes with favorable fertility outcomes in women, and because they are directly linked to an increase in progesterone levels, the potential utility of these hormone-regulated cell biological structures in predicting or improving implantation in a clinical setting holds promise. In this review, we aim to generate interest in pinopodes from the broader cell biology and endocrinology communities, re-examine methodologies in pinopode research, and identify priorities for future investigation of pinopode structure and function in women's reproductive health.

Luteal Phase Support in IVF: Comparison Between Evidence-Based Medicine and Real-Life Practices

Background: Luteal phase support (LPS) in assisted reproduction cycles has been widely investigated in recent years. Although progesterone represents the preferential product for luteal phase supplementation in cycles with fresh embryo transfer, there is ongoing debate as to when to start, which is the best route, dosage and duration, and whether there is a place for additional agents. Nevertheless, fertility specialists do not always adhere to evidence-based recommendations in their clinical practice. The aim of this worldwide web-based survey is to document the currently used protocols for luteal phase support and appraisal tendencies of drug prescription behavior and to compare these to the existing evidence-based literature. Material and Methods: A questionnaire was developed and sent by secure e-mail to 1,480 clinicians involved in ART worldwide. One hundred and forty-eighth clinicians from 34 countries returned completed questionnaires. Results: Progesterone support is usually started on the day of oocyte retrieval. Eighty percent of clinicians applied the administration of vaginal progesterone only. Intramuscular progesterone was prescribed by 6%, while oral progestin or subcutaneous progesterone were each prescribed by 5% of clinicians, respectively. Progesterone was administered until 8-10 weeks' gestation by 35% and 12 weeks by 52% of respondents. Conclusions: Vaginal administration was the preferred route for luteal phase support. The reported emerging use of the oral route confirms the expected shift in clinical practice as a result of recent evidence showing a reassuring safety score of oral progestins. In spite of the lack of evidence supporting the continuation of luteal support until 12 weeks' gestation, this practice was adhered to by more than half of the clinicians surveyed, highlighting the difference between evidence-based medicine and real-life practices.

Cumulative live birth rate in freeze-all cycles is comparable to that of a conventional embryo transfer policy at the cleavage stage but superior at the blastocyst stage

OBJECTIVE

To determine whether the freeze-all policy ensures a higher efficacy in terms of cumulative live birth rate (CLBR) in comparison with a conventional fresh/frozen embryo transfer (ET) approach in patients with normal ovarian response.

DESIGN

Retrospective, matched, multicenter cohort study.

SETTING

Private IVF centers.

PATIENT(S)

This study analyzed 564 completed IVF cycles in which an average of 12-18 oocytes were retrieved. In 435 cycles the conventional strategy was applied, with initial ET followed by frozen embryo replacements, whereas in 129 cycles the freeze-all policy was performed, with elective cryopreservation and deferred use of all viable embryos.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary endpoint was CLBR. The secondary endpoint was cumulative clinical pregnancy rate.

RESULT(S)

Overall, statistically comparable CLBRs were achieved in the fresh/frozen and freeze-all groups (45.5% vs. 53.5%). Stratification of data for age and number of retrieved oocytes confirmed the absence of differences between the two groups. In a subanalysis in which the day of ET and cryopreservation were taken into account, a similar outcome was achieved in cleavage-stage groups (45.6% vs. 46.4%), whereas when ET was performed at the blastocyst stage the CLBR was significantly higher in the freeze-all group (45.3% vs. 66.7%).

CONCLUSION(S)

Our CLBR analysis indicates that clinical performance of the freeze-all policy is equivalent to that of the conventional strategy when ET is carried out at the cleavage stage. However, it seems to be superior if associated with cryopreservation and transfer at the blastocyst stage.

The endometrium during and after ovarian hyperstimulation and the role of segmentation of infertility treatment

Controlled ovarian hyperstimulation (COH) is a crucial part of assisted reproductive technologies (ART) that resulted in a substantial increase in pregnancy rates from in vitro fertilization (IVF). However, in spite of the apparent benefit of COH on an increase in the number of follicles and the number of oocytes retrieved, allowing for extended embryo culture and enabling the selection of the best quality embryo for transfer, several reports has shown that the supraphysiologic hormonal levels may indeed have a detrimental effect at the endometrial level. The current article revises the pathophysiological mechanisms through which ovarian stimulation may negatively affect endometrial receptivity. Also, the evidence is analyzed explaining how segmentation of IVF treatment may allow us to overcome the deleterious effects of hyperstimulation on endometrial receptivity. Deferred embryo transfer may be performed in a more physiologic uterine environment in a subsequent cycle, improve endometrial receptivity, decrease uterine contractility, diminishes the impact of premature luteinization and allow individualized stimulation according to the level of response.

In Freeze-All Strategy, Cumulative Live Birth Rate (CLBR) Is Increasing According to the Number of Blastocysts Formed in Women <40 Undergoing Intracytoplasmic Sperm Injection (ICSI)

Background: Elective freezing of all embryos, followed by frozen-thawed ET cycles emerged to prevent risk of Ovarian Hyperstimulation Syndrome and to allow endometrium recovery after Controlled Ovarian Stimulation, leading to better IVF outcomes. Blastocyst Freeze-all policy can minimize the number of abnormal embryos and consequently failed ETs, but its efficacy in terms of cumulative rates has not been studied yet. Methods: A prospective cohort observational study was carried out in Assisting Nature, Center of Assisted Reproduction and Genetics, in Thessaloniki, Greece from January 2014 until December 2017. 244 patients- normal or high responders- underwent COS with recFSH and Freeze-all policy with blastocyst culture. The included patients were 18-39 years and achieved clinical pregnancy and/or live birth or had all their vitrified blastocysts transferred in subsequent frozen-thawed cycles. Women were divided into four groups (group A: 1-2 blastocysts frozen; group B: 3-4; group C: 5-6; group D ≥7 blastocysts frozen) or seven groups (group I: 1-2 blastocysts frozen, group II: 3, group III: 4, group IV: 5, group V: 6, group VI: 7; group VII: ≥8 blastocysts frozen), according to the numerical range or to the absolute number of vitrified blastocysts, respectively. Results: The main outcome of the study was the CLBR achieved by frozen-thawed ETs, according to the number of the vitrified blastocysts. Higher CLBR are expected, when at least 3 blastocysts are formed (group B: 65.2%) and at least 2 frozen-thawed ETs are performed, reaching highest rates (88%) by group D (≥7 vitrified blastocysts). Similarly, CLBR is significantly increasing with the absolute number of the vitrified blastocysts, ranging from 20%, when 1-2 blastocysts are vitrified (group I) to 82.4% when ≥8 blastocysts are available. Conclusions: A higher number of vitrified blastocysts is associated with higher CLBR in women <40 years old- normal/high responders- following Freeze-all policy. Adopting Freeze-all strategy after blastocyst culture can contribute to improve delivery outcome after IVF, in terms of CLBR. The number of the total cryopreserved blastocysts produced might reflect the quality of the oocyte and can successfully predict the pregnancy outcome. The blastulation rate can be a robust criterion to segment or not an IVF cycle.

Electroacupuncture facilitates implantation by enhancing endometrial angiogenesis in a rat model of ovarian hyperstimulation

Controlled ovarian hyperstimulation (COH) impairs the synchronized development of endometrium and embryo, resulting in the failure of embryo implantation. Here, we investigated what effects electroacupuncture had on embryo implantation in COH rats. Female rats were randomly assigned to four groups: normal (N), model (M), electroacupuncture (EA), and electroacupuncture pretreatment (PEA). Rats in groups M, EA, PEA were injected with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin to establish the COH model. Rats in group EA received electroacupuncture treatment from the PMSG injection day to the 3rd day of pregnancy (D3), while those in group PEA received electroacupuncture treatment for 3 days before the PMSG day and continuing to D3. Furthermore, another 30 female rats who received the same treatment as the rats in group PEA were injected with siVEGFR2 into uterine lumen. The endometrial microvascular density (MVD) and the expression levels of vascular endothelial growth factor-A, angiopoietin-1, and fibroblast growth factor-2 were significantly lower in groups M than in groups N and PEA. The percentage of dolichos biflorus agglutinin positive uterine natural killer cells in groups N, EA and PEA was higher than that in group M. After the siVEGFR2 injection, the protein expression levels of vascular endothelial growth factor receptor 2 (VEGFR2), PI3K, p-AKT and p-ERK, the embryo number and the MVD were significantly reduced. In conclusion, electroacupuncture can facilitate embryo implantation in COH rats by activating the VEGFR2/PI3K/AKT and VEGFR2/ERK signaling pathways which have a positive relationship with endometrial angiogenesis.

Effects of EBN on embryo implantation, plasma concentrations of reproductive hormones, and uterine expressions of genes of PCNA, steroids, growth factors and their receptors in rats

This study was conducted to determine the effect of edible bird's nest (EBN) supplement on uterine function and embryo-implantation rate. A total of 24 adult female rats, divided equally into four groups, were treated with different doses of EBN for 8 weeks. In the last week of treatment, intact fertile male rats were introduced into each group (three per group) for overnight for mating. On day 7 post-mating (post-implantation), blood samples were collected from the hearts of anaesthetised rats that were later sacrificed. The uteri were removed for assessment of embryo implantation rate, histological and electron microscopic examination, and immunohistochemical analyses. Results showed that as the concentration of EBN supplemented increased, the pregnancy and embryo implantation rates were also increased in the treated groups; significantly at G3 and G4. Although histological evaluation did not show much difference among the groups, scanning electron microscopic examination showed enhanced development of elongated microvilli and pinopods in G4. Results also revealed up-regulated expressions of epidermal growth factor (EGF), EGF receptor (EGFR), vascular endothelial growth factor (VEGF), proliferating cell nulear antigen (PCNA), and progesterone and estrogen receptors (P₄R, E₂R) in the uteri of treated groups. Moreover, plasma E₂, P₄, growth hormone (GH) and prolactin (P) levels were higher (p < 0.05) in G3 and G4. The EBN increased the antioxidant (AO) and total AO capacities (TAC) and reduced oxidative stress (OS) levels in pregnant rats. In conclusion, findings of this study revealed that EBN enhances fertility and embryo implantation rate via promoting proliferation and differentiation of uterine structures as evidenced by the upregulation of the expressions of steroid receptors, EGF, EGFR, VEGF, and PCNA in the uterus. Furthermore, observations of improved growth of ultrastructural pinopods that assist in embryo attachment with uterine epithelium, increased concentrations of E₂, P₄, GH and P levels, as well as increased AO capacities with reduced OS levels in the treated groups might reflect additional possible mechanisms by which EBN enhances embryo implantation rate and pregnancy success.

The Deferred Embryo Transfer Strategy Seems Not to be a Good Option After Repeated IVF/ICSI Cycle Failures

Objective:

The aim of this study was to assess whether a deferred frozen–thawed embryo transfer (Def-ET) offers any benefits compared to a fresh ET strategy in women who have had 2 or more consecutive in vitro fertilization (IVF)/intracytoplasmic injection (ICSI) cycle failures.

Design:

An observational cohort study in a tertiary referral care center including 416 cycles from women with a previous history of 2 or more consecutive IVF/ICSI failures cycles. Both Def-ET and fresh ET strategies were compared using univariate and multivariate logistic regression models. The main outcome measured was the cumulative live birth rate (CLBR).

Results:

A total of 416 cycles were included in the analysis: 197 in the fresh ET group and 219 in the Def-ET group. The CLBR was not significantly different between the fresh and Def-ET groups (58/197 [29.4%] and 57/219 [26.0%], respectively, P = .437). In addition, after the first ET, there was no significant difference in the live birth rate between the fresh ET and Def-ET groups (50/197 [25.4%] vs 44/219 [20.1%], respectively). Multivariate logistic regression analysis indicated that compared to the fresh strategy, the Def-ET strategy was not associated with a higher probability of live birth.

Conclusions:

In cases with 2 or more consecutive prior IVF/ICSI cycle failures, a Def-ET strategy did not result in better ART outcomes than a fresh ET strategy.

Pinopode score around the time of implantation is predictive of successful implantation following frozen embryo transfer in hormone replacement cycles

STUDY QUESTION

Is pinopode measurement of any prognostic value?

SUMMARY ANSWER

Pinopode expression was significantly associated with the occurrence of pregnancy after frozen embryo transfer.

WHAT IS KNOWN ALREADY

Pinopodes are expressed in the endometrium during the implantation period. Pinopode measurement has been proposed as a marker of endometrial receptivity.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was conducted at the Center of Reproductive Medicine, Sir Run Run Shaw Hospital, between 2014 and 2016, recruiting 172 women with infertility and undergoing frozen embryo transfer following IVF treatment. Among 172 participants, 46 women took part in the first study to quantify the daily changing pattern of pinopodes 3-7 days after the initiation of progesterone therapy in the hormone replacement cycles and the remaining 126 women with infertility participated in a study to examine the relationship between pinopode count and pregnancy outcome following frozen embryo transfer in hormone replacement cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The mean age of participants was 29 years old. All participants received an artificial hormone replacement protocol capable of supporting successful implantation. Endometrial biopsies from 46 women were obtained 3, 4, 5, 6 and 7 days after the initiation of progesterone therapy (P + 3, n = 6; P + 4, n = 6; P + 5, n = 11; P + 6, n = 13; P + 7, n = 10, respectively). Another 126 endometrial biopsies were obtained precisely 6 days after the initiation of progesterone. Scanning electron microscopy was used to capture the pinopode images, followed by use of the image J program to quantify the count and subtype of the pinopodes.

MAIN RESULTS AND THE ROLE OF CHANCE

We found that at least 60 microscopic fields were necessary to achieve a reproducible result. An intra-observer variability study showed good agreement between two measurements regarding the developing pinopode (DP) subtype (r = 0.95) and the fully developed pinopode (FDP) subtype (r = 0.86) but not for the regressing (RP) pinopode subtype (r = 0.39). The proportion of DP/total pinopodes (TP) declined rapidly form day P + 4 to a minimum on day P + 6. The percentage of FDP/TP increased rapidly from day P + 4 to reach a peak on day P + 6. On the other hand, the percentage of RP/TP reached a peak on day P + 7. Participants who conceived had a significantly (P = 0.011) higher percentage of FDP/TP on day P + 6 and significantly (P = 0.005) lower percentage of DP/TP on the same day compared with participants who did not become pregnant. Using a scoring system incorporating the percentages of DP and FDP, it was found that the pregnancy rate and the embryo implantation rate of women with a high pinopode score (82.3%; 63.0%) was significantly (P = 0.001; P = 0.046) higher than that of women with a low pinopode score (53.3%; 46.7%), respectively. There remains a possibility that the observations could have arisen due to chance.

LIMITATIONS, REASONS FOR CAUTION

This study examined pinopode count and subtype in the HRT cycles, and it is uncertain whether the same observations apply to in natural cycles.

WIDER IMPLICATIONS OF THE FNDINGS

Pinopodes have been questioned as a potential marker of endometrial receptivity for many years. Our results suggested that pinopode measurement may be of value in predicting pregnancy.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the grants from the general project of medicine and health in Zhejiang Province of China (2015KYA142; 2018KY106), the Key Research and Development Program of Zhejiang Province (2017C03022) and the National Natural Science Foundation of China (81701514).The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript. We have no competing interests to declare.

TRIAL REGISTRATION NUMBER

ISRCTN26300668.

Rapid freezing versus Cryotop vitrification of mouse two-cell embryos

Objective

To compare our in-house method of embryo freezing with Cryotop vitrification in terms of immediate survival, subsequent cleavage and blastocyst formation, and cell numbers in blastocysts.

Methods

Two-cell mouse embryos were randomly allocated into three groups: a non-frozen control group (group 1, n=300), a group that underwent Cryotop vitrification (group 2, n=300), and a group that underwent our in-house freezing method (group 3, n=300).

Results

There were no significant differences between groups 2 and 3 in the immediate survival rate (96.3% vs. 98.6%, respectively; p=0.085), the further cleavage rate (91.7% vs. 95.0%, respectively; p=0.099), or the blastocyst formation rate (80.7% vs. 78.6%, respectively; p=0.437). The cell numbers in the blastocysts from groups 1, 2, and 3 were comparable (88.99±10.44, 88.29±14.79, and 86.42±15.23, respectively; p=0.228). However, the percentage of good-quality blastocysts in the Cryotop vitrification group was significantly higher than in the group in which our in-house method was performed, but was lower than in the control group (58.0%, 37.0%, and 82.7%, respectively; p<0.001).

Conclusion

At present, our method is inferior to the commercial Cryotop vitrification system. However, with further improvements, it has the potential to be useful in routine practice, as it is easier to perform than the current vitrification system.

The deferred embryo transfer strategy improves cumulative pregnancy rates in endometriosis-related infertility: A retrospective matched cohort study

Background

Controlled ovarian stimulation in assisted reproduction technology (ART) may alters endometrial receptivity by an advancement of endometrial development. Recently, technical improvements in vitrification make deferred frozen-thawed embryo transfer (Def-ET) a feasible alternative to fresh embryo transfer (ET). In endometriosis-related infertility the eutopic endometrium is abnormal and its functional alterations are seen as likely to alter the quality of endometrial receptivity. One question in the endometriosis ART-management is to know whether Def-ET could restore optimal receptivity in endometriosis-affected women leading to increase in pregnancy rates.

Objective

To compare cumulative ART-outcomes between fresh versus Def-ET in endometriosis-infertile women.

Materials and methods

This matched cohort study compared def-ET strategy to fresh ET strategy between 01/10/2012 and 31/12/2014. One hundred and thirty-five endometriosis-affected women with a scheduled def-ET cycle and 424 endometriosis-affected women with a scheduled fresh ET cycle were eligible for matching. Matching criteria were: age, number of prior ART cycles, and endometriosis phenotype. Statistical analyses were conducted using univariable and multivariable logistic regression models.

Results

135 in the fresh ET group and 135 in the def-ET group were included in the analysis. The cumulative clinical pregnancy rate was significantly increased in the def-ET group compared to the fresh ET group [58 (43%) vs. 40 (29.6%), p = 0.047]. The cumulative ongoing pregnancy rate was 34.8% (n = 47) and 17.8% (n = 24) respectively in the Def-ET and the fresh-ET groups (p = 0.005). After multivariable conditional logistic regression analysis, Def-ET was associated with a significant increase in the cumulative ongoing pregnancy rate as compared to fresh ET (OR = 1.76, CI95% 1.06–2.92, p = 0.028).

Conclusion

Def-ET in endometriosis-affected women was associated with significantly higher cumulative ongoing pregnancy rates. Our preliminary results suggest that Def-ET for endometriosis-affected women is an attractive option that could increase their ART success rates. Future studies, with a randomized design, should be conducted to further confirm those results.

[Effects of raloxifene at two different doses for ovulation induction on endometrial pinopodes in mice during the implantation window]

OBJECTIVE

To compare the expression of pinopodes, the marker of endometrial receptivity, during the implantation window in Kunming mice stimulated with two different doses of raloxifene (RAL).

METHODS

Forty-eight 8-week-old female Kunming mice were randomly divided into 4 groups (n=12), namely saline group, clomiphene citrate (CC, 18 mg/kg) group, RAL (33 mg/kg) group and RAL (44 mg/kg group). In each group, the mice received intragastric administration of 1 mL of normal saline containing CC or RAL at the specified doses or saline only as indicated for ovulation induction, once daily for 2 days. The mice received then injection with 5 IU human chorionic gonadotropin (HCG) and mated and on day 4.5 of gestation, the pregnant mice were sacrificed for examination of the uterus with scanning electron microscopy.

RESULTS

Abundant and well developed pinopodes were observed in the endometrium of the mice in the 2 RAL groups and in the saline control group. The mice in CC group showed obviously reduced endometrial pinopodes with poor development.

CONCLUSIONS

RAL at two different doses does not obviously affect the expression of pinopodes in the uterine epithelium of mice, suggesting the safety of RAL at these two doses for ovulation induction without causing adverse effects on endometrial receptivity.

HCG administration after endogenous LH rise negatively influences pregnancy rate in modified natural cycle for frozen-thawed euploid blastocyst transfer: a pilot study

PURPOSE

The aim of the present study was to evaluate whether in a modified natural cycle (modified-NC) for a frozen-thawed single euploid blastocyst transfer, a critical LH value, above which human chorionic gonadotropin (hCG) administration should be avoided, may be defined.

METHODS

One hundred and sixty-seven patients underwent modified natural cycle in order to transfer a single frozen-thawed euploid blastocyst. All embryos were obtained by intracytoplasmic sperm injection and were biopsied at the blastocyst stage and analyzed by means of array comparative genomic hybridization (aCGH). Ovulation was induced using 10.000 IU hCG when the mean follicle diameter was at least of 17 mm, independently from LH values. The primary end points were the hCG-positive test and clinical pregnancy. The interim analysis showed that LH value ≥ 13 mIU/ml on the day of hCG injection may negatively influence the clinical results, suggesting that in this condition, it should be advisable waiting for spontaneous ovulation.

RESULTS

Among patients who received hCG for ovulation induction, the hCG-positive test and clinical pregnancy rates in modified-NC were significantly lower in cycles with LH ≥ 13 mIU/ml in respect to those with LH < 13 mIU/ml (45.4 vs 73.3 and 36.4 vs 65.9%, in LH ≥ 13 and LH < 13 groups, respectively). In patients with LH value ≥ 13 mIU/ml, hCG administration led to significantly lower rates of hCG-positive test (45.4 vs 74.5% in hCG administration and spontaneous ovulation groups, respectively) and clinical pregnancy (36.4 vs 64.7% in hCG administration and spontaneous ovulation groups, respectively). The baseline patient characteristics were comparable in all groups.

CONCLUSIONS

The findings of this study highlight that LH elevation ≥ 13 mIU/ml prior to hCG administration may negatively affect clinical pregnancy rates in modified-NC for single euploid blastocyst transfer. The LH determination should be routinely performed during follicular monitoring. In the presence of LH level ≥ 13 mIU/ml, hCG administration should be avoided, and the embryo transfer should be planned only after spontaneous follicular rupture.

The effect of laser-assisted hatching on pregnancy outcomes of cryopreserved-thawed embryo transfer: a meta-analysis of randomized controlled trials

It is well known that laser-assisted hatching (LAH) is the most popular and ideal embryo hatching technology, but the relevance to pregnancy outcomes of cryopreserved-thawed embryo transfer (ET) is controversial. The purpose of this meta-analysis was to evaluate the effects of LAH on pregnancy outcomes of cryopreserved-thawed ET. We searched for relevant studies published in the PubMed, EMBASE, and Cochrane Central databases up to March 2017. This meta-analysis was primarily used to evaluate the effect of laser-assisted hatching on assisted reproductive outcomes: clinical pregnancy, embryo implantation, multiple pregnancy, miscarriage, and live birth. Using the Mantel-Haenszel fixed effects model and random effects model, we determined the summary odds ratios (OR) with 95% confidence intervals (CIs). There were 12 randomized controlled trials (more than 2574 participants) included in our analysis. The rates of clinical pregnancy (OR = 1.65, 95% CI = 1.24-2.19, I ² = 49), implantation (OR = 1.59, 95% CI = 1.06-2.38, I ² = 82%), multiple pregnancy (OR = 2.30, 95% CI = 1.30-4.07, I ² = 33%), miscarriage (OR = 0.86, 95% CI = 0.50-1.48, I ² = 0%), and live birth (OR = 1.09, 95% CI = 0.77-1.54, I ² = 0%) revealed comparable results for both groups. In summary, this meta-analysis demonstrates that LAH is related to a higher clinical pregnancy rate, embryo implantation rate, and multiple pregnancy rate in women with cryopreserved-thawed embryos. However, LAH is unlikely to increase live birth rates and miscarriage rates. Due to the small sample evaluated in the pool of included studies, large-scale, prospective, randomized, controlled trials are required to determine if these small effects are clinically relevant.

Fresh embryos versus freeze-all embryos - transfer strategies: Nuances of a meta-analysis

Objective

The present meta-analysis aimed to evaluate whether the freeze-all strategy (Freeze/All-ET) could bring about improvements in the clinical assisted reproductive technique (ART) outcomes when compared with the fresh embryo transfer strategy (Fresh-ET) in patients undergoing an ART cycle in accordance with the mean number of oocytes collected.

Methods

A systematic review based on electronic searches in databases (PubMed, EMBASE, Web of Science, SCOPUS, and Cochrane Central Register of Controlled Trials) was carried out to identify randomized controlled trails (RCTs) comparing ART outcomes between fresh-embryo transfers versus elective frozen-embryo transfers up to February of 2017. Four reviewers independently evaluated abstracts, validity assessment and data extraction. Odds Ratio (OR) values with a 95% confidence interval (CI), and heterogeneity were evaluated.

Results

Five RCTs were included as targets for data extraction and meta-analysis purposes. The results of this meta-analysis were divided into two parts (Freeze/All-ET versus Fresh-ET): Part I- All trials in which the mean number of collected oocytes was >12 and <21 for ongoing pregnancy rate (OR=1.24; 95%CI=1.06-1.44), clinical pregnancy rate (OR=1.19; 95%CI=0.98-1.43), live birth rate (OR= 1.39; 95%CI=0.99-1.95), and miscarriage rate (OR=0.68; 95%CI=0.46-1.00); Part II- Three studies where the mean number of oocytes retrieved was >12 and <15 for ongoing pregnancy rate (OR=1.17; 95%CI=1.00-1.38), clinical pregnancy rate (OR=1.34; 95%CI=0.79-2.28), live birth rate (OR= 1.24; 95%CI=1.00-1.55), and miscarriage rate (RR=0.68; 95%CI=0.46-1.02).

Conclusions

The freeze-all strategy could be favorable when high numbers of oocytes are collected, signaling an association between higher ovarian stimulation and consequent impairment of endometrial receptivity. However, when the mean number of oocytes collected is <15, the freeze-all strategy does not appear to be advantageous.

Effect of 2,3',4,4',5-Pentachlorobiphenyl Exposure on Endometrial Receptivity and the Methylation of HOXA10

Polychlorinated biphenyls (PCBs) are one of the most common endocrine-disrupting chemicals and have obvious toxicity on human reproductive development. The aim of our study was to investigate the toxicity of chronic 2,3',4,4',5-pentachlorobiphenyl (PCB 118) exposure on embryo implantation and endometrial receptivity, with the possible mechanism of DNA methylation involved. Virgin CD-1 female mice (3 weeks old) were housed and orally treated with PCB 118 (0, 1, 10, 100 μg/kg) for a month. After mating with fertile males, the pregnant mice were killed on gestation day 4.5. Compared with the control group, implantation failures were observed in 1 μg/kg PCB 118- and 100 μg/kg PCB 118-treated groups. Abnormal endometrial morphology with open uterine lumens and densely compact stromal cells and poorly developed pinopodes were substantially in response to PCB 118 doses above, as well as the significant downregulation of implantation-associated genes (estrogen receptor 1, homeobox A10 [HOXA10], integrin subunit beta 3) and hypermethylation in the promoter region of HOXA10 further. It was confirmed that chronic exposure to PCB 118 produced an increased number of implantation failures in association with a defective uterine morphology during the implantation period. Alterations in methylation of HOXA10 could explain, at least in part, the mechanism of effects of PCB 118 exposure on the implantation process.

Deferred Frozen Embryo Transfer: What Benefits can be Expected from this Strategy in Patients with and without Endometriosis?

Progress with cryopreservation techniques have enabled development of the deferred frozen-thawed embryo transfer (DET) strategy as an alternative to relying on fresh embryo transfers.

With DET, the entire embryo cohort is cryopreserved, and embryo transfer is then performed in a subsequent cycle that takes place separately from the controlled ovarian stimulation (COS).

Initially developed to limit the risk of ovarian hyperstimulation syndrome that occurs with high responders, this strategy has been applied extensively with other populations in an effort to improve implantation rates. The assumption is that COS, which is essential for in vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) procedures to obtain a multi-follicular development, could have a detrimental impact on the endometrium as a result of greatly elevated levels of steroids. It is currently not clear whether the DET strategy can be generally applied to all women requiring an IVF/ICSI procedure.

The objectives of this literature review regarding DET, were hence: (i) to present the scientific background that contributed to extensive adoption of this technique, (ii) to detail the pregnancy outcomes and potential obstetric and neonatal consequences, (iii) to report on its ability to prevent risks induced by COS, and (iv) to propose indications for the DET strategy in clinical practice.

Immunohistochemical and ultrastructural analysis of the effect of omega-3 on embryonic implantation in an experimental mouse model

OBJECTIVE

Implantation is the first step to a healthy pregnancy. Omega-3 supplementation is common to use during pregnancy, for its antioxidant and membrane stabilising effect. In this study we have aimed to study the effect of Omega-3 supplementation on implantation in a mouse model by immunohistochemical methods and electron microscopic evaluation.

MATERIALS AND METHODS

Mice were randomized into three groups to receive standard food, Omega-3 400 mg/kg and Omega-3 1000 mg/kg one menstrual cycle before mating. Mice were sacrificed on third day of estimated implantation and uterine horns were evaluated immunohistochemically for staining of Laminin and Leukemia Inhibitory Factor (LIF) and ultrastructural morphology.

RESULTS

Laminin and LIF immunoreactivity were increased signifcantly in the high dose group when compared to the control and low-dose groups in lumen epithelium basal membrane, gland epithelium basal membrane and endometrial stroma. Electron-microscopic evaluation showed a decrease in epithelial height and microvilli loss in the high dose groups.

CONCLUSION

Omega-3 supplementation increased implantation markers Laminin and LIF and decreased epithelial height and microvilli thus seems to prepare the endometrium for a favorable environment of implantation.

Progesterone/estradiol ratio <0.25 on the day of human chorionic gonadotropin administration is associated with adverse pregnancy outcomes in prolonged protocols for in vitro fertilization/intracytoplasmic sperm injection

OBJECTIVE

It has been suggested that a progesterone/estradiol ratio (P/E2) ≥ 1.0 on the day of human chorionic gonadotropin (hCG) administration indicates premature luteinization and might be associated with an adverse pregnancy; however, a lower limit of this ratio has not been determined. We aimed to identify a lower limit of P/E2 that correlates significantly with an increase in adverse pregnancies in patients undergoing a prolonged in vitro fertilization/intracytoplasmic sperm injection therapy.

MATERIALS AND METHODS

This retrospective analysis involved 7451 patients who received the first cycle of in vitro fertilization/intracytoplasmic sperm injection therapy treatment at the Reproductive and Genetic Hospital of Citic-Xiangya between January 2008 and April 2012. Patients were stratified into six groups according to their P/E2 on the day of hCG administration. Primary pregnancy outcomes, rates of implantation, clinical pregnancy, ongoing pregnancies, spontaneous abortions, and live births were recorded. The association between P/E2 on the day of hCG administration and primary pregnancy outcomes was assessed using logistic regression analysis.

RESULTS

The rates of implantation (23.85-33.44%), clinical pregnancy (47.42-67.12%), ongoing pregnancy (40.83-61.48%), and live birth (34.40-57.65%) were significantly decreased in patients with a P/E2 < 0.25. These indicators were significantly associated with P/E2, but no significant correlation was observed between P/E2 and early spontaneous abortion rate.

CONCLUSION

P/E2 < 0.25 on the day of hCG administration was associated with adverse pregnancy outcomes in extended treatments of gonadotropin-releasing hormone agonist IVF/ICSI.

Frozen embryo transfer prevents the detrimental effect of high estrogen on endometrium receptivity

OBJECTIVE

To investigate whether serum levels of estradiol affect reproductive outcomes of normoresponder women undergoing fresh embryo transfer (ET) versus frozen-thawed ET (FET).

MATERIAL AND METHODS

Two hundred fifty-five normoresponder women underwent fresh ET in their first or second in vitro fertilization cycle. Ninety-two women with negative pregnacy test results underwent FET. Clinical and ongoing pregnancy rates, implantation, and live birth rates of women undergoing fresh ET versus FET were compared.

RESULTS

One hundred forty-seven (57.65%) out of the 255 normoresponder women receiving FET had positive beta-human chorionic gonadotrophin (hCG) results. The remaining 108 women had negative beta-hCG results. The clinical pregnancy rates of the fresh ET group were found as 55.69% (n=142). Ninety-two of the 108 women with failed pregnancies underwent FET; 72.83% had positive beta-hCG results (n=67), and 70.65% had clinical pregnancy (n=65). Both biochemical and clinical pregnancy rates of women undergoing FET increased significantly (p<0.012 and p<0.013, respectively). Ongoing pregnancy (60.87% vs. 52.94%) and live birth rates (59.87% vs. 48.63%) were similar in both fresh and FET groups. Serum E2 levels of women who failed to conceive were significantly higher than those women did conceive. Serum progesterone levels of women who conceived versus those that did not were similar.

CONCLUSION

The detrimental effect of high serum estradiol levels on endometrial receptivity could be prevented by FET.

Optimal embryo transfer strategy in poor response may include freeze-all

PURPOSE

In this retrospective cohort study, we investigated the best embryo transfer strategy in ICSI cycles with ≤4 oocytes collected at oocyte retrieval.

METHODS

Women who underwent antagonist co-treatment COS for ICSI treatment between January 2010 and December 2015 at a private ART clinic (N = 2263). Eight hundred seventy-nine women (group 1) had ≤4 oocytes collected at oocyte retrieval, of whom 645 (group A) had cleavage stage embryo transfer (ET), and 234 (group B) had blastocyst ET. One thousand three hundred eighty-four women (group 2) had 10-15 oocytes collected at oocyte retrieval, of whom 676 (group C) had cleavage stage ET, and 708 women (group D) had blastocyst ET. Blastocyst vitrification was performed using the Cryotop method and FET using artificial cycles.

RESULTS

In group 1, the cancellation rate was significantly lower in group A (25.2 vs 38 %). The pregnancy rate (PR), clinical PR, implantation rate (IR), and live birth rate (LBR) per ET and per oocyte retrieval were all lower in group A. The clinical PR, IR, and LBR per ET of vitrified-warmed blastocyst ET were significantly the highest. In group 2, the cycle cancellation rate was significantly lower in group C (3.5 vs 13.4 %). The PR, clinical PR, and IR per ET and per oocyte retrieval were all lower in group C. The LBR per ET was significantly lower, but the LBR per oocyte retrieval was not significantly lower in group C. Again, the PR, clinical PR, and IR per ET of vitrified-warmed blastocyst ET were significantly the highest.

CONCLUSIONS

Day 5 ET strategy has been reserved for normal or high responders. The improved pregnancy outcomes from blastocyst culture and cryopreservation may challenge ART to extend this benefit to poor responders.

Freeze-all cycle for all normal responders?

PURPOSE

The purpose of this study is to evaluate the freeze-all strategy in subgroups of normal responders, to assess whether this strategy is beneficial regardless of ovarian response, and to evaluate the possibility of implementing an individualized embryo transfer (iET) based on ovarian response.

METHODS

This was an observational, cohort study performed in a private IVF center. A total of 938 IVF cycles were included in this study. The patients were submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone (GnRH) antagonist protocol and a cleavage-stage day 3 embryo transfer. We performed a comparison of outcomes between the fresh embryo transfer (n = 523) and the freeze-all cycles (n = 415). The analysis was performed in two subgroups of patients based on the number of retrieved oocytes: Group 1 (4-9 oocytes) and Group 2 (10-15 oocytes).

RESULT(S)

In Group 1 (4-9 retrieved oocytes), the implantation rates (IR) were 17.9 and 20.5% (P = 0.259) in the fresh and freeze-all group, respectively; the ongoing pregnancy rates (OPR) were 31 and 33% (P = 0.577) in the fresh and freeze-all group, respectively. In Group 2 (10-15 oocytes), the IR were 22.1 and 30.1% (P = 0.028) and the OPR were 34 and 47% (P = 0.021) in the fresh and freeze-all groups, respectively.

CONCLUSION(S)

Although the freeze-all policy may be related to better in vitro fertilization (IVF) outcomes in normal responders, these potential advantages decrease with worsening ovarian response. Patients with poorer ovarian response do not benefit from the freeze-all strategy.

A direct healthcare cost analysis of the cryopreserved versus fresh transfer policy at the blastocyst stage

A cost analysis covering direct healthcare costs relating to IVF freeze-all policy was conducted. Normal- and high- responder patients treated with a freeze-all policy (n = 63) compared with fresh transfer IVF (n = 189) matched by age, body mass index, duration and cause of infertility, predictive factors for IVF (number of oocytes used for fertilization) and study period, according to a 1:3 ratio were included. Total costs per patient (€6952 versus €6863) and mean costs per live birth were similar between the freeze-all strategy (€13,101, 95% CI 10,686 to 17,041) and fresh transfer IVF (€15,279, 95% CI 13,212 to 18,030). A mean per live birth cost-saving of €2178 (95% CI -1810 to 6165) resulted in a freeze-all strategy owing to fewer embryo transfer procedures (1.29 ± 0.5 versus 1.41 ± 0.7); differences were not significant. Sensitivity analysis revealed that the freeze-all strategy remained cost-effective until the live birth rate is either higher or only slightly lower (≥-0.59%) in the freeze-all group compared with fresh cycles. A freeze-all policy does not increase costs compared with fresh transfer, owing to negligible additional expenses, i.e. vitrification, endometrial priming and monitoring, against fewer embryo transfer procedures required to achieve pregnancy.

Osteopontin and Integrin αvβ3 Expression during the Implantation Window in IVF Patients with Elevated Serum Progesterone and Oestradiol Level

Background: To explore whether endometrial receptivity is determined by osteopontin (OPN) and integrin αvβ3 expression in women with elevated serum progesterone (P) and/or oestradiol (E₂) who are undergoing in vitro fertilisation (IVF). Methods: According to serum hormone levels on the day of HCG administration, 33 infertile women were divided into 3 groups: the high E₂, high P, and high E₂ and P groups. The control group included 11 fertile, healthy women. Endometrial biopsy was performed on ovulation day + 7 to + 8 for all study participants, and the mRNA and protein expression levels of OPN and integrin αvβ3 were analyzed. Result: No statistically significant differences regarding OPN and integrin αvβ3 expression were found between infertile patients in the high P, high E₂, high E₂ and P and control groups. There was no significant correlation between OPN and integrin αvβ3 staining intensity during the implantation window biopsy in any of the groups studied. Conclusion: Endometrial OPN and integrant αvβ3 expression/co-expression is not impaired during the window of implantation in patients with high P, high E₂, or high E₂ and P levels. The clinical value of assessing endometrial receptivity with OPN and integrin αvβ3 seems to be uncertain.

The endometrial preparation for frozen-thawed euploid blastocyst transfer: a prospective randomized trial comparing clinical results from natural modified cycle and exogenous hormone stimulation with GnRH agonist

PURPOSE

The aim of the study was to evaluate two methods of endometrial preparation for frozen-thawed single euploid blastocyst transfer: modified natural and artificial cycle with GnRH-agonist pituitary suppression.

METHODS

In this prospective, controlled randomized trial, a total of 236 patients undergoing infertility treatment were randomized in 1:1 ratio; 118 received a frozen-thawed single euploid blastocyst transfer in a modified natural cycle and 118 in an artificial cycle with GnRH-agonist pituitary suppression. In the artificial protocol, GnRH-agonist combined with estradiol valerate was administered. In the natural protocol, only final oocyte maturation was induced using human chorionic gonadotropin administration. The primary end-points were the clinical pregnancy and implantation rates; the secondary end-points were the cost-benefit in terms of drug cost and the number of visits and the woman psychological distress caused by the treatment.

RESULTS

No significant differences were found in clinical pregnancy, implantation, and miscarriage rates between protocols. The number of clinical and ultrasound controls and the number of laboratory dosages and venous samplings were similar in both study groups. No significant differences were found between the groups in the anxiety and depression values before the start of treatment, on the days of progesterone administration, the blastocyst transfer, and pregnancy test.

CONCLUSIONS

The findings of this study evidence that in case of frozen-thawed single euploid blastocyst transfer, both protocols are equally effective in terms of clinical outcomes, cost-benefit, and patient compliance. The choice of endometrial preparation protocol should be based on women menstrual and ovulatory characteristics or otherwise on patient need for cycle planning.

TRIAL REGISTRATION

www.clinicaltrials.gov with number NCT02378584.

Endometrial Receptivity Markers in Mice Stimulated With Raloxifene Versus Clomiphene Citrate and Natural Cycles

Ovulation induction therapy with clomiphene citrate can suppress endometrial receptivity. Raloxifene may be an alternative therapeutic for women with ovulatory disorders. This study aimed to compare the expression of endometrial receptivity markers, including homeobox gene 10 (HOXA10), integrin β3, and leukemia inhibitory factor (LIF), as well as pinopode production during the implantation window in mice stimulated with raloxifene and clomiphene citrate and natural cycles. Thirty-six 8-week-old female Kunming mice were randomly divided into 3 groups (n = 12) and administered daily raloxifene (22 mg/kg), clomiphene citrate (18 mg/kg), and normal saline (1 mL), respectively, by gavage. Two days later, mice were injected with 5 IU human chorionic gonadotropin and mated. Successfully mated female animals were identified with vaginal plugs designated gestation day 1. At day 4.5, pregnant donor mice were euthanized, and uterus samples were collected for immunohistochemistry, quantitative polymerase chain reaction, Western blot, and scanning electron microscopy analyses. Homeobox gene 10, integrin β3, and LIF messenger RNA (mRNA) and protein levels were significantly higher in the raloxifene-treated animals compared with the clomiphene citrate group (all P < .05) but not significantly different from saline group values, except for LIF and integrin β3 mRNA levels (P < .05). Pinopodes were abundant and well developed in the raloxifene and saline groups; however, in the clomiphene citrate-treated mice, fewer and poorly developed pinopodes were obtained. In mice, raloxifene had no effect on HOXA10, integrin β3, and LIF expression as well as pinopode production, suggesting it has no adverse effects on endometrial receptivity. Raloxifene may provide a viable alternative oral ovulation induction agent to clomiphene citrate.

Maternal hCG concentrations in early IVF pregnancies: associations with number of cells in the Day 2 embryo and oocytes retrieved

STUDY QUESTION

Do number of cells in the transferred cleavage stage embryo and number of oocytes retrieved for IVF influence maternal hCG concentrations in early pregnancies?

SUMMARY ANSWER

Compared with transfer of a 2-cell embryo, transfer of a 4-cell embryo results in higher hCG concentrations on Day 12 after transfer, and more than 20 oocytes retrieved were associated with low hCG concentrations.

WHAT IS KNOWN ALREADY

Maternal hCG concentration in very early pregnancy varies considerably among women, but is likely to be an indicator of time since implantation of the embryo into the endometrium, in addition to number and function of trophoblast cells.

STUDY DESIGN, SIZE, DURATION

We followed 1047 pregnancies after IVF/ICSI from oocyte retrieval until Day 12 after embryo transfer. Women were recruited in Norway during the years 2005-2013.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Successful pregnancies after transfer of one single embryo that had been cultured for 2 days were included. Maternal hCG was quantified on Day 12 after embryo transfer by chemiluminescence immunoassay, which measures intact hCG and the free β-hCG chain. Information on a successful pregnancy, defined as birth after >16 weeks, was obtained by linkage to the Medical Birth Registry of Norway.

MAIN RESULTS AND THE ROLE OF CHANCE

Transfer of a 4-cell embryo resulted in higher maternal hCG concentrations compared with transfer of a 2-cell embryo (134.8 versus 87.8 IU/l, P < 0.05). A high number of oocytes retrieved (>20) was associated with low hCG concentrations (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

The factors studied explain a limited part of the total variation of hCG concentrations in early pregnancy. Although embryo transfer was performed at the same time after fertilization, we do not know the exact time of implantation. A further limitation to our study is that the number of pregnancies after transfer of a 2-cell embryo was small (27 cases).

WIDER IMPLICATIONS OF THE FINDINGS

Number of cells in the transferred embryo and number of oocytes retrieved may influence the conditions and timing for embryo implantation in different ways and thereby influence maternal hCG concentrations. Such knowledge may be important for interpretation of hCG concentrations in early pregnancy.

Morphological Changes and Expression of Cytokine After Local Endometrial Injury in a Mouse Model

OBJECTIVE

To establish a mouse model for endometrial injury and determine the underlying mechanism regarding its favorable effect on embryo implantation.

STUDY DESIGN

Female Kunming mice were randomly allocated into 4 groups: group I, normal control; group II, injury procedure control; and group III and group IV, the mice being scratched with a blunt syringe on the right uterine horn or both, respectively. All the mice were mated with the males during the next estrus phase. The number of implanted embryos on each side of uterus was calculated on day 8 of pregnancy. The endometrial samples were taken on day 4 of pregnancy, and the local morphological changes and cytokine expressions were examined.

RESULTS

Compared to group II, our results showed that in group IV (1) there were significantly higher numbers of implanted embryos, (2) the endometrial glands and vasculatures in stroma were obviously increased and the pinopodes were abundant and well developed, and (3) the local levels of cytokines leukemia inhibitory factor (LIF) and oncostatin M (OSM) messenger RNA and protein expression were significantly increased.

CONCLUSIONS

Local mechanical injury on mouse uteri enhanced endometrial receptivity and improved embryo implantation, which were correlated with the characteristic changes in endometrial morphology and the upregulation of LIF and OSM gene and protein expression.

Freeze-all policy: is it time for that?

PURPOSE

This publication will evaluate the available evidence in the literature comparing fresh embryo transfer (ET) and elective frozen-thawed embryo transfer (FET) regarding the possible interference of controlled ovarian stimulation (COS) in implantation and endometrial receptivity, IVF safety, and obstetric and perinatal outcomes.

METHODS

We performed a review in the literature of the available evidence comparing fresh to elective FET (freeze-all policy).

RESULTS

The improvements made in cryopreservation techniques have led to few or no detrimental effects to the embryo and have resulted in no consequences to the offspring when compared to fresh embryos; this has allowed reproductive practitioners to create the freeze-all policy (when all viable embryos are electively cryopreserved in the fresh cycle and transferred in a posterior cycle). There are increasing concerns about the adverse effects associated with COS over the endometrial and uterine environments, as well as with the safety of COS in pregnancies that have originated from fresh ET during in vitro fertilization (IVF) treatments. COS may contribute to modifications in the endometrium, which might be related to poorer outcomes when fresh ET is performed. It has been suggested that obstetric and perinatal outcomes in pregnancies resulting from fresh ET are poorer when compared with those that occur after FET. In cycles with fresh ET, there is still a risk of ovarian hyperstimulation syndrome (OHSS).

CONCLUSION

There is growing evidence in the literature suggesting better IVF outcomes, and decreased obstetric and perinatal morbidity when adopting the freeze-all policy instead of fresh ET.

Effect of Zhuyun recipe on endometrial pinopode expression in mice with embryonic implantation dysfunction and ovulation stimulation

Zhuyun recipe (ZYR) is a traditional Chinese medicine that has been widely used as an infertility treatment for a number of years. Although the therapeutic effects are desirable and satisfactory, the therapeutic mechanism of ZYR remains poorly understood. In the present study, pinopodes were investigated as an important morphological marker of endometrial receptivity, in order to further investigate the therapeutic mechanism of ZYR. The expression of pinopodes during the implantation window was observed using scanning electron microscopy in mice with induced ovarian stimulation (OS) and embryo implantation dysfunction (EID). A marked decrease in the number of fully developed pinopodes was observed on the endometrial surface in the OS and EID model mice, which was in accordance with the decreased pregnancy rate and number of embryonic implantation sites when compared with the control. Following treatment with ZYR, the spatial and temporal expression of pinopodes in the OS and EID mice was found to be similar to the control mice. In conclusion, ZYR was demonstrated to improve endometrial receptivity in OS and EID mice through significant improvements in the spatial and temporal expression of pinopodes.

Sophoricoside fails the embryo implantation by compromising the uterine endometrial receptivity at implantation "window" of pregnant mice

Sophoricoside (SOPH) is an isoflavone glycoside isolated from the fruits of Sophora japonica. Since its first isolation in 1961, there are rare findings about the effects of SOPH on reproductive system. In the present study, the pregnant mice administrated by different doses of SOPH were used to explore the effect of SOPH on embryo implantation, especially on the endometrial receptivity. The statistical results showed that the number of implanted embryos was gradually declining along the increasing dose of SOPH. When the administrated dose of SOPH was 600 mg/kg per day, great changes were observed in the exposed uterine morphology and up-regulated progesterone receptor (PR) and down-regulated estrogen receptor α (ERα), E-cadherin, matrix metalloproteinase-2 (MMP-2) and integrin β3 were also found in SOPH-exposed uterine. These findings demonstrated that SOPH exposure reduced the number of implanted embryos in a dose-dependent manner and failed the embryo implantation through altering the morphology of uterine and compromising the endometrial receptivity.

Clinical rationale for cryopreservation of entire embryo cohorts in lieu of fresh transfer

Recent dramatic increases in success rates with frozen-thawed embryo transfer (FET) are encouraging, as are numerous findings of several reduced risks with FET when compared with fresh transfer. These reduced risks include low birth weight and prematurity, among others. However, FET is also associated with increased risks of macrosomia and large for gestational age. There have been reports of greater implantation and pregnancy rates with FET than with fresh autologous embryo transfer, suggesting superior endometrial receptivity in the absence of ovarian stimulation. As cryo-technology evolves, there is potential for further increase in FET success rates, but for now it may be best to follow an individualized approach, balancing fresh transfer and embryo cohort cryopreservation options while considering patient characteristics, cycle parameters, and clinic success rates.