Oocyte, embryo and blastocyst cryopreservation in ART: systematic review and meta-analysis comparing slow-freezing versus vitrification to produce evidence for the development of global guidance

Oocyte Vitrification Temporarily Turns on Oxidation-Reduction Process Genes in Mouse Preimplantation Embryos

We aim to understand how oocyte vitrification impacts subsequent mouse preimplantation embryo development at molecular level. We profiled transcriptomics of fertilized preimplantation embryos derived from mouse vitrified-warmed oocytes. Concomitantly, we evaluated epigenetic markers in fertilized preimplantation embryos. We found that oocyte vitrification did not affect the fertilization and cleavage process but delayed embryo development until blastocyst stage. RNA sequencing revealed that 1575 genes were profoundly altered in the 2-cell stage embryos developed from vitrified oocytes. The most significantly altered biological pathway was "oxidation-reduction process." Such profound transcriptomics change was associated with decreased level of oocyte-specific histone H1FOO in zygote and 2-cell stage. Transcriptome alteration due to oocyte vitrification was less pronounced as embryos develop into the morula stage. Oocyte vitrification temporarily changes transcriptomics in early preimplantation embryos. Targeting oxidation-reduction pathway might be a potential therapeutic strategy to improve embryo quality and long-term embryo survival.

Embryo Selection Based on Morphological Parameters in a Single Vitrified-Warmed Blastocyst Transfer Cycle

The process of selecting a good quality embryo to improve the pregnancy outcomes is very important. The aim of our study was to elaborate the embryo selection process in a single vitrified-warmed blastocyst transfer (VBT) cycle by analyzing pre-vitrified and post-warmed blastocyst morphological factors to improve pregnancy outcomes. In this retrospective cohort study, we performed 329 single VBT cycles. The pre-vitrified and post-warmed morphological factors of all blastocysts were analyzed. Logistic regression analysis was conducted to select the independent morphological factor associated with ongoing pregnancy. The expansion of blastocoel (mid blastocoel; aOR 2.27, 95% CI.0.80-6.42, p = 0.12, expanded blastocoel; aOR 3.15, 95% CI.1.18-8.44, p = 0.02) in a pre-vitrified blastocyst and the grade of inner cell mass (ICM) (grade B; aOR 0.47, 95% CI.0.27-0.83, p = 0.01, grade C; aOR 0.22, 95% CI 0.09-0.56 p < 0.01) in post-warmed blastocysts significantly predicted the ongoing pregnancy. After fertilization, the embryo developed as a blastocyst on day 5 (day 5) showed a higher ongoing pregnancy than that on day 6 (day 6) (aOR 0.50, 95% CI.0.26-0.94, p = 0.03). The results suggest that while selecting a vitrified-warmed blastocyst in a single VBT cycle, the day 5 vitrified blastocyst should be considered, and a higher expansion grade in the pre-vitrified blastocyst should be selected. Our study has shown that post-warmed ICM grade tends to be a predictive indicator for the selection of the best blastocyst and allows for successful pregnancy, with ongoing pregnancy in a single blastocyst transfer.

On Ice: The impact of vitrification on the use of eggs in fertility treatment

The possibility to freeze sperm and embryos has long been available to men and women facing infertility as a result of an illness or medical treatment. However, the ability to successfully cryopreserve human eggs is comparatively recent. The introduction and increasing use of egg vitrification from the mid-2000s onwards, alongside the use of intracytoplasmic sperm injection, has seen improved ongoing clinical pregnancy rates compared with slow freezing methods. Despite concerns, the technology has been widely embraced by the scientific community and in recent years has been applied in a greater variety of contexts. In this short perspective paper, we consider two specific applications for the vitrification of human eggs in routine assisted reproduction practice: social egg freezing and the use of frozen eggs in egg donation. We suggest that vitrification is transforming the reproductive landscape in novel and complex ways and that we must be alert to the challenges, complexities and ethics of such developments, especially for those who may be excluded or marginalised by these techniques.

Effect of vitrification on biogenesis pathway and expression of development-related microRNAs in preimplantation mouse embryos

Vitrification of embryos has been known as the most efficient cryopreservation method in assisted reproductive technology clinics. Vitrification of preimplantation embryo might be associated with altered gene expression profile and biochemical changes of vitrified embryos. Stringent regulation of gene expression in early embryonic stages is very critical for normal development. In the present study, we investigated the effect of vitrification on the canonical miRNA biogenesis pathway, and also the expression of developmental related miRNAs, in 8-cell and blastocyst mouse embryos. Although the expression pattern of the miRNA biogenesis pathway genes differed between 8-cell and blastocyst mouse embryos, vitrification did not affect the expression level of these genes in preimplantation embryos. The expression levels of miR-21 and let-7a were significantly decreased in vitrified 8-cell embryos and fresh blastocysts when compared with fresh 8-cell embryos. The expression of Stat3 was significantly reduced in blastocysts after vitrification. The alteration in the expression pattern of miRNAs, due to their mode of action, can affect broad downstream key developmental signaling pathways. Therefore, the blastocyst stage is the preferred point for embryo vitrification as they are less susceptible to cryo-damages regarding the stability of miRNAs related to the developmental and implantation competence of embryo.

Gender-specific aspects related to type of fertility preservation strategies and access to fertility care

Survivorship is an area of paramount importance to be addressed as early as possible after cancer diagnosis by all health care providers. On this regard, cancer care in young patients often poses several age-related considerations among which fertility and pregnancy-related issues have a crucial role. According to the available guidelines on the topic, all patients with cancer diagnosed during their reproductive years should be provided a proper oncofertility counselling before starting anticancer treatments. This is an important step in order to inform patients about the potential treatment-induced gonadotoxicity and the available strategies for fertility preservation so that they can be referred as early as possible to fertility specialists if potentially interested in these options.In this manuscript, we aim to provide an up to date overview on the available efficacy and safety data with the main strategies for fertility preservation in male and female cancer patients in order to help optimising the oncofertility counselling performed by healthcare providers involved in cancer care and dealing with young patients. In male patients with cancer, sperm cryopreservation is the standard technique for fertility preservation. Oocyte/embryo cryopreservation, ovarian tissue cryopreservation and temporary ovarian suppression with luteinising hormone-releasing hormone agonists during chemotherapy are the main options in female patients with cancer.A multidisciplinary management building a strong network between fertility and oncology/haematology units is crucial to properly address fertility care in all young patients with cancer, at both diagnosis and during oncologic follow-up. Discussing fertility and pregnancy-related issues with young patients with cancer has to be considered mandatory nowadays keeping in mind that returning to a normal life (including the possibility to have a family and to live with as few side effects as possible) should be considered an important ambition in cancer care in the 21st century .

D6 blastocyst transfer on day 6 in frozen-thawed cycles should be avoided: a retrospective cohort study

Background

There is no definitive evidence about the suitable timing to transfer blastocysts formed and cryopreserved on day 6 (D6 blastocysts) in frozen-thawed embryo transfer (FET) cycles. This study aimed to investigate the suitable timing to transfer D6 blastocysts in FET cycles and to identify factors affecting clinical pregnancy rate (CPR) and early miscarriage rate (EMR) in FET cycles with blastocysts.

Methods

This retrospective cohort study included 1788 FET cycles with blastocysts. There were 518 cycles with D6 blastocysts, and 1270 cycles with blastocysts formed and cryopreserved on day 5 (D5 blastocysts) (D5 group). According to the blastocyst transfer timing, the cycles with D6 blastocysts were divided into cycles with D6 blastocysts transferred on day 5 (D6-on-D5 group, 103 cycles) and cycles with D6 blastocysts transferred on day 6 (D6-on-D6 group, 415 cycles). The chi-square test, independent t-test or Mann-Whitney test, and logistic regression analysis were used for data analysis.

Results

The CPR and implantation rate (IR) were significantly higher in the D6-on-D5 group than in the D6-on-D6 group (55.3% vs. 37.3%, 44.8% vs. 32.6%, P < 0.01). The CPR and IR were significantly higher in the D5 group than in the D6-on-D5 group (66.0% vs. 55.3%, 62.1% vs. 44.8%, P < 0.05), and the EMR was significantly lower in the D5 group than in the D6-on-D5 group (11.2% vs. 21.1%, P < 0.05). Logistic regression analysis demonstrated that transfer D6 blastocysts on day 5, instead of day 6, could significantly increase the CPR (odds ratio[OR]: 2.031, 95% confidence interval (CI): 1.296–3.182, P = 0.002). FET cycles with D6 blastocysts transferred on day 5 had a higher EMR than those with D5 blastocysts (OR: 2.165, 95% CI: 1.040–4.506, P = 0.039). Hormone replacement therapy (HRT) cycles exhibited a higher EMR than natural cycles (OR: 1.953, 95% CI: 1.254–3.043, P = 0.003), while no difference was observed in the CPR (P > 0.05).

Conclusions

These results indicate that the suitable timing to transfer D6 blastocysts in FET cycles may be day 5, and D6 blastocyst transfer on day 6 in FET cycles should be avoided. D6 blastocysts transfer and HRT cycles may be associated with a higher EMR.

Is vanishing twin syndrome associated with adverse obstetric outcomes of ART singletons? A systematic review and meta-analysis

PURPOSE

The objective of our meta-analysis was to estimate the effect of VTS on obstetric outcomes of ART singletons.

METHODS

PubMed, Embase, MEDLINE, and ClinicalTrials.gov were searched up to January 2019 to find studies reporting the obstetric outcomes of ART singletons with VTS. Dichotomous data were expressed as odds ratios (OR) with 95% confidence intervals (CI). Continuous data were expressed as weighted mean difference (WMD) with 95% CI.

RESULTS

A total of 17 observational studies encompassing more than 60,000 ART singletons were included in this meta-analysis. The impact of VTS on singletons was highly dependent on the definition of VTS, precisely, the vanishing timing and intrauterine growth stage. When VTS happened at or before 14 weeks, regardless of intrauterine growth stage, there were no differences in terms of gestational age (GA) [WMD = - 0.08, 95% CI = - 0.27, 0.10], preterm birth (< 37 weeks) (PTB) [OR = 1.23, 95% CI = 0.89, 1.70], and low birth weight (< 2.5 kg) (LBW) [OR = 1.56, 95% CI = 1.00, 2.43] in original singletons versus singleton with VTS. On the contrary, VTS occurred after 14 weeks was associated with significantly shorter GW and lower BW, as well as higher risks of PTB and LBW. When the sac reduced in VTS was an empty gestational sac, there would be no differences in GW, PTB, and LBW between singletons versus singletons with VTS, whereas the loss of a fetus with cardiac-activity was associated with adverse obstetric outcomes.

CONCLUSIONS

This meta-analysis suggests whether or not VTS is harmful to obstetric outcomes is highly dependent on the vanishing timing and intrauterine growth stage.

Recent trends in embryo disposition choices made by patients following in vitro fertilization

PURPOSE

To assess longitudinal trends in in vitro fertilization (IVF) patients' choices for disposing of cryopreserved embryos.

METHODS

This is a retrospective cohort study of embryo disposition forms submitted between January 2000 and February 2020 at a university-based fertility clinic. Primary outcome was disposition decision. Binary and multivariable logistic regression were performed to determine odds ratios (OR) for decisions according to female age, education, race, religion, state of residence, area deprivation index based on zip code, and IVF pregnancy history. We also assessed disposition year, storage duration, and number of stored embryos.

RESULTS

Forms were reviewed from 615 patients; 50.6% chose to discard embryos, 45.4% donated to research, and 4.1% chose reproductive donation. In the regression model, two factors were significantly associated with donation to research: female listing "no preference" or declining to list religious preference (OR 2.56, 95%CI 1.44-4.54) and live birth of multiples after IVF (OR 1.58, 95%CI 1.05-2.36). Before 2012, females younger than age 30 at storage were equally likely to choose to donate embryos to research as discard them. However, between 2013 and 2020, females younger than 30 were significantly more likely to discard than donate embryos for research (OR 2.87, 95%CI 1.13-7.28).

CONCLUSION

Since 2013, the majority of patients younger than 30 at storage have chosen to discard cryopreserved embryos. Before then, patients were more likely to donate embryos for research. To ensure sufficient embryos are available for research, young patients, who are most likely to have cryopreserved embryos, should be counseled about options for donation.

Cryopreservation of Mammalian Oocytes: Slow Cooling and Vitrification as Successful Methods for Cryogenic Storage

Two basic methods for the laboratory-focused cryopreservation of mammalian oocytes are described, based on work with murine oocytes. One method uses a relatively low concentration of the cryoprotectant propanediol plus sucrose and requires controlled rate cooling equipment to achieve a slow cooling rate. This method has also produced live births from cryopreserved human oocytes. The second method, which is described here, employs a high concentration of the cryoprotectant dimethyl sulfoxide plus a low concentration of polyethylene glycol. This is a vitrification method, which involves ultra-rapid cooling by plunging standard straws into liquid nitrogen vapor, hence avoiding the need for specialized equipment, but requires technical ability to manipulate the oocytes quickly in the highly concentrated cryoprotectant solutions. Murine oocytes that have been vitrified using this technique have resulted in live births. Vitrification using other cryoprotectant mixtures is now a popular clinically accepted method for cryobanking of human oocytes.

What impact does oocyte vitrification have on epigenetics and gene expression?

Children conceived by assisted reproductive technologies (ART) have a moderate risk for a number of adverse events and conditions. The question whether this additional risk is associated with specific procedures used in ART or whether it is related to the intrinsic biological factors associated with infertility remains unresolved. One of the main hypotheses is that laboratory procedures could have an effect on the epigenome of gametes and embryos. This suspicion is linked to the fact that ART procedures occur precisely during the period when there are major changes in the organization of the epigenome. Oocyte freezing protocols are generally considered safe; however, some evidence suggests that vitrification may be associated with modifications of the epigenetic marks. In this manuscript, after describing the main changes that occur during epigenetic reprogramming, we will provide current information regarding the impact of oocyte vitrification on epigenetic regulation and the consequences on gene expression, both in animals and humans. Overall, the literature suggests that epigenetic and transcriptomic profiles are sensitive to the stress induced by oocyte vitrification, and it also underlines the need to improve our knowledge in this field.

Assisted hatching of vitrified-warmed blastocysts prior to embryo transfer does not improve pregnancy outcomes

Objective

This study aims to determine the impact of assisted hatching (AH) on pregnancy outcomes in vitrified-warmed blastocyst transfers, and evaluate if embryo expansion or morphology influences outcomes.

Methods

A retrospective cohort study was performed including vitrified-warmed blastocyst transfers at our clinic between 2013 and 2017. Of the 2165 embryo transfers, 1986 underwent laser AH and 179 were non-assisted hatched (NAH). The primary outcome was live birth. Secondary outcomes included conception, implantation, clinical pregnancy, clinical pregnancy loss, and monozygotic twinning (MZT).

Results

AH and NAH groups had similar rates of conception (38.7% vs 42.1%), implantation (26.2% vs 27.3%), clinical pregnancy (29.1% vs 30.3%), clinical pregnancy loss (24.0% vs 17.8%), live birth (19.9% vs 20.5%), and MZT (2.08% vs 2.86%). Five pairs of dichorionic/diamniotic twins resulted from single embryo transfers. AH of embryos with expansion grades ≤3 was associated with lower rates of conception (32.5% vs 44.3%%, p < 0.05) and clinical pregnancy (24.0% vs 32.8%, p < 0.05).

Conclusion

AH prior to transfer of vitrified-warmed blastocysts was not associated with improved pregnancy outcomes. The identification of dichorionic/diamniotic twins from single blastocyst transfers challenges the previously held notion that dichorionic/diamniotic MZTs can only occur from division prior to the blastocyst stage. Prospective studies are needed to validate the novel finding of lower rates of conception and clinical pregnancy after AH in embryos with lower expansion grade.

ART in Europe, 2016: results generated from European registries by ESHRE

STUDY QUESTION

What are the reported data on cycles in ART, IUI and fertility preservation (FP) interventions in 2016 as compared to previous years, as well as the main trends over the years?

SUMMARY ANSWER

The 20th ESHRE report on ART and IUI shows a progressive increase in reported treatment cycle numbers in Europe, with a decrease in the number of transfers with more than one embryo causing a reduction of multiple delivery rates (DR), as well as higher pregnancy rates and DR after frozen embryo replacement (FER) compared to fresh IVF and ICSI cycles, while the outcomes for IUI cycles remained stable.

WHAT IS KNOWN ALREADY

Since 1997, ART aggregated data generated by national registries, clinics or professional societies have been collected, analysed by the European IVF-monitoring Consortium (EIM) and reported in 19 manuscripts published in Human Reproduction and Human Reproduction Open.

STUDY DESIGN SIZE DURATION

Yearly collection of European medically assisted reproduction (MAR) data by EIM for ESHRE. The data on treatments performed between 1 January and 31 December 2016 in 40 European countries were provided by either National Registries or registries based on personal initiatives of medical associations and scientific organizations.

PARTICIPANTS/MATERIALS SETTING METHODS

In all, 1347 clinics offering ART services in 40 countries reported a total of 918 159 treatment cycles, involving 156 002 with IVF, 407 222 with ICSI, 248 407 with FER, 27 069 with preimplantation genetic testing, 73 927 with egg donation (ED), 654 with IVM of oocytes and 4878 cycles with frozen oocyte replacement (FOR). European data on IUI using husband/partner's semen (IUI-H) and donor semen (IUI-D) were reported from 1197 institutions offering IUI in 29 and 24 countries, respectively. A total of 162 948 treatments with IUI-H and 50 467 treatments with IUI-D were included. A total of 13 689 FP interventions from 11 countries including oocyte, ovarian tissue, semen and testicular tissue banking in pre-and postpubertal patients were reported.

MAIN RESULTS AND THE ROLE OF CHANCE

In 20 countries (18 in 2015) with a total population of approximately 325 million inhabitants, in which all ART clinics reported to the registry, a total of 461 401 treatment cycles were performed, corresponding to a mean of 1410 cycles per million inhabitants (range 82-3088 per million inhabitants). In the 40 reporting countries, after IVF the clinical pregnancy rates (PR) per aspiration and per transfer in 2016 were similar to those observed in 2015 (28.0% and 34.8% vs 28.5% and 34.6%, respectively). After ICSI, the corresponding rates were also similar to those achieved in 2015 (25% and 33.2% vs 26.2% and 33.2%). After FER with own embryos, the PR per thawing is still on the rise, from 29.2% in 2015 to 30.9% in 2016. After ED, the PR per fresh embryo transfer was 49.4% (49.6% in 2015) and per FOR 43.6% (43.4% in 2015). In IVF and ICSI together, the trend towards the transfer of fewer embryos continues with the transfer of 1, 2, 3 and ≥4 embryos in 41.5%, 51.9%, 6.2% and 0.4% of all treatments, respectively (corresponding to 37.7%, 53.9%, 7.9% and 0.5% in 2015). This resulted in a proportion of singleton, twin and triplet DRs of 84.8%, 14.9% and 0.3%, respectively (compared to 83.1%, 16.5% and 0.4%, respectively in 2015). Treatments with FER in 2016 resulted in twin and triplet DR of 11.9% and 0.2%, respectively (vs 12.3% and 0.3% in 2015). After IUI, the DRs remained similar at 8.9% after IUI-H (7.8% in 2015) and at 12.4% after IUI-D (12.0% in 2015). Twin and triplet DRs after IUI-H were 8.8% and 0.3%, respectively (in 2015: 8.9% and 0.5%) and 7.7% and 0.4% after IUI-D (in 2015: 7.3% and 0.6%). The majority of FP interventions included the cryopreservation of ejaculated sperm (n = 7877 from 11 countries) and of oocytes (n = 4907 from eight countries).

LIMITATIONS REASONS FOR CAUTION

As the methods of data collection and levels of completeness of reported data vary among European countries, the results should be interpreted with caution. A number of countries failed to provide adequate data about the number of initiated cycles and deliveries.

WIDER IMPLICATIONS OF THE FINDINGS

The 20th ESHRE report on ART and IUI shows a continuous increase of reported treatment numbers and MAR-derived livebirths in Europe. Being already the largest data collection on MAR in Europe, continuous efforts to stimulate data collection and reporting strive for future quality control of the data, transparency and vigilance in the field of reproductive medicine.

STUDY FUNDING/COMPETING INTERESTS

The study has no external funding and all costs were covered by ESHRE. There are no competing interests.

Cancer fertility preservation: a report from a Brazilian social program

OBJECTIVE

To present clinical and laboratory data of a Brazilian social program for cancer fertility preservation.

METHODS

We carried out a descriptive observational study between July 2011 and December 2018. 246 patients were included from a social program in a private assisted reproduction clinic in Santo André/Brazil for oocyte cryopreservation before starting oncological treatment.

RESULTS

246 cancer patients resorted to fertility preservation before initiating cancer treatment. These were diagnosed with 27 different types of cancer, and the breast type is the most prevalent. 2528 MII oocytes (mean of 10.3 oocytes per patient) were vitrified. Four patients thawed their oocytes to submit in vitro fertilization, three had embryos transferred and one achieved pregnancy.

CONCLUSION

Preservation of fertility offers patients, especially at reproductive age, a viable way to perform their cancer treatment without compromising future gestation. It is important that professionals duly counsel oncological patients so, if they wish, they can have the possibility to guarantee her fertility preserved.

Fertility preservation in borderline ovarian tumor patients and survivors

Borderline ovarian tumors (BOTs) represent around 15% of all epithelial ovarian cancer. Around one third of those patients is under 40 and has not completed childbearing when the tumor is diagnosed. Cancer survivors are more and more concerned about their future fertility since a large proportion of those with BOTs are young. Whatever the tumor stage, information regarding future fertility after treatment and fertility preservation (FP) options must be delivered to all patients before treatment. A multidisciplinary team will discuss and propose personalized treatment and FP strategies. Nowadays, the FP options offered to patients with BOT are the followings: i) minimal invasive conservative surgery, ii) oocyte cryopreservation after controlled ovarian stimulation (COS) or in vitro maturation (IVM) and iii) ovarian tissue cryopreservation. Generally, the most common strategy to preserve future fertility is represented by minimal invasive conservative surgery. However, with the remarkable success and evolution of assisted reproductive technologies (ART) - notably progress and efficiency in COS and oocyte vitrification - have led to offer another potential approach for FP consisting in oocyte cryopreservation. Several COS protocols, such as random start or dual stimulation associating tamoxifen or aromatase inhibitors with gonadotropins provide similar results when compared to standard protocols while providing safety by minimizing the risk of high estrogen exposure. When COS is contraindicated, oocyte cryopreservation can still be possible throw IVM. Even though, oocyte competence after IVM is lower than that obtained after COS. A less used approach is cryopreservation of ovarian tissue, consisting in freezing ovarian cortex fragments for a future thawing and graft. Some concerns and limitations regard the ovarian cortex graft and the risk of reintroducing malignant cells once performed. Nonetheless, the latter it is the only option in prepubertal patients.

Developmental Plasticity in Response to Embryo Cryopreservation: The Importance of the Vitrification Device in Rabbits

Simple Summary

This study was conducted to demonstrate how embryo manipulation techniques incur phenotypic changes throughout life. This study reports the first evidence demonstrating that the vitrification device used is not a trivial decision, providing valuable information about how the cooling–warming rates during vitrification can be partly responsible of the postnatal phenotypic variations.

Abstract

In this study, we evaluated the effect of embryo vitrification using two different devices on adulthood phenotype in rabbits. In vitro development, prenatal embryo survival, body weight, growth performance, haematological and biochemical peripheral blood analysis, reproductive performance, and lactation performance traits were compared between the experimental groups. They derived from naturally-conceived embryos (NC), fresh-transferred embryos (FT), vitrified-transferred embryos using mini-straw (VTs), or vitrified-transferred embryos using Cryotop (VTc). Straw-vitrified embryos exhibited lower in vitro developmental rates and in vivo survival rates following embryo transfer compared to its Cryotop-vitrified counterparts. Moreover, the VTs group exhibited higher foetal losses than VTc, FT, and NC groups. Independently of the vitrification device, vitrified-transferred (VT) offspring showed a skewed sex ratio in favour of males, and an increased birth bodyweight. In contrast, postnatal daily growth was diminished in all ART (i.e., FT and VT) animals. In adulthood, significant differences in body weight between all groups was founded—all ART progenies weighed less than NC animals and, within ART, VT animals weighed less than FT. For VT groups, weight at adulthood was higher for the VTs group compared with the VTc group. Peripheral blood parameters ranged between common values. Moreover, no differences were found in the fertility rates between experimental groups. Furthermore, similar pregnancy rates, litter sizes, and the number of liveborns were observed, regardless of the experimental group. However, decreased milk yield occurred for VTc and FT animals compared to VTs and NC animals. A similar trend was observed for the milk composition of dry matter and fat. Concordantly, reduced body weight was found for suckling kits in the VTc and FT groups compared to VTs and NC animals. Our findings reveal that developmental changes after the embryo vitrification procedure could be associated with an exhibition of the embryonic developmental plasticity. Moreover, to our best knowledge, this study reports the first evidence demonstrating that the vitrification device used is not a trivial decision, providing valuable information about how the cooling–warming rates during vitrification can be partly responsible of the postnatal phenotypic variations.

Molecular analysis of lipid uptake- and necroptosis-associated factor expression in vitrified-warmed mouse oocytes

BACKGROUND

We had previously demonstrated that vitrification reduces the levels of certain phospholipid classes, and that oocytes from aged mice show a similar lipidome alteration, even without vitrification. In the current investigation, we examined if vitrification-warming of mouse oocytes from young and aged mice causes any changes in molecular aspects of lipid-associated features.

METHODS

Metaphase II (MII) stage oocytes were harvested from young (10-14-week-old) and aged (45-54-week-old) mice by a superovulation regime with PMSG followed by hCG. We examined the status of the intracellular lipid pool and the integrity of the plasma membrane by staining oocytes with BODIPY 500/510 and CellMask live dyes. Expression of lipid uptake- and necroptosis-associated genes was assessed by quantitative PCR analyses, in oocytes from young and old mice, before and after vitrification. Localization patterns of two crucial necroptosis proteins, phosphorylated MLKL (pMLKL) and phosphorylated RIPK1 (pRIPK1) were examined in mouse oocytes by immunofluorescence staining. Necrostain-1 (Nec1), an inhibitor of RIPK1, was used to examine if RIPK1 activity is required to maintain oocyte quality during vitrification.

RESULTS

We confirmed that vitrified-warmed oocytes from aged mice showed noticeable decrease in both CellMask and BODIPY 500/510 dyes. Among the lipid uptake-associated genes, Cd36 expression was higher in oocytes from aged mice. Necroptosis is a type of programmed cell death that involves damage to the plasma membrane, eventually resulting in cell rupture. The expression of necroptosis-associated genes did not significantly differ among groups. We observed that localization patterns of pMLKL and pRIPK1 were unique in mouse oocytes, showing association with microtubule organizing centers (MTOCs) and spindle poles. pMLKL was also localized on kinetochores of MII chromosomes. Oocytes treated with Nec1 during vitrification showed a decreased survival rate, indicating the importance of RIPK1 activity in oocyte vitrification.

CONCLUSIONS

We report that oocytes from aged mice show differential expression of CD36, which suggests that CD36-mediated lipid uptake may be influenced by age. We also show for the first time that pMLKL and pRIPK1 exhibit unique localization pattern in mouse oocytes and this may suggest role(s) for these factors in non-necroptosis-associated cellular processes.

Perinatal outcome in children born after assisted reproductive technologies

Over the past 40 years access and effectiveness of assisted reproductive technologies (ART) have increased, and to date more than 8 million children have been conceived after ART globally. Most pregnancies resulting from ART are uncomplicated and result in the birth of healthy children. Yet, it is well known that pregnancies following ART are more likely to be affected by obstetric complications such as hypertensive disorders in pregnancy, preterm birth, and low birth weight compared with spontaneously conceived pregnancies. ART children are also at increased risk of birth defects. The majority of the problems arise as a result of multiple pregnancies and can be reduced by transferring a single embryo, thereby avoiding multiple pregnancies. New ART technologies are constantly introduced, and monitoring of the health of ART children is crucial.

DuoStim - a reproducible strategy to obtain more oocytes and competent embryos in a short time-frame aimed at fertility preservation and IVF purposes. A systematic review

Recent evidence suggests that follicular development occurs in a wave-like model during the ovarian cycle, where up to three cohorts of follicles are recruited to complete folliculogenesis. This understanding overtakes the previous dogma stating that follicles grow only during the follicular phase of the menstrual cycle. Therefore, in in vitro fertilization (IVF), novel protocols regarding ovarian stimulation have been theorized based on the use of gonadotrophins to prompt the growth of antral follicles at any stage of the menstrual cycle. These unconventional protocols for ovarian stimulation aim at a more efficient management of poor-prognosis patients, otherwise exposed to conflicting outcomes after conventional approaches. DuoStim appears among these unconventional stimulation protocols as one of the most promising. It combines two consecutive stimulations in the follicular and luteal phases of the same ovarian cycle, aimed at increasing the number of oocytes retrieved and embryos produced in the short time-frame. This protocol has been suggested for the treatment of all conditions requiring a maximal and urgent exploitation of the ovarian reserve, such as oncological patients and poor responders at an advanced maternal age. At present, data from independent studies have outlined the consistency and reproducibility of this approach, which might also reduce the drop-out between consecutive failed IVF cycles in poor-prognosis patients. However, the protocol must be standardized, and more robust studies and cost-benefit analyses are needed to highlight the true clinical pros and cons deriving from DuoStim implementation in IVF.

Luteal phase anovulatory follicles result in the production of competent oocytes: intra-patient paired case-control study comparing follicular versus luteal phase stimulations in the same ovarian cycle

STUDY QUESTION

Are the mean numbers of blastocysts obtained from sibling cohorts of oocytes recruited after follicular phase and luteal phase stimulations (FPS and LPS) in the same ovarian cycle similar?

SUMMARY ANSWER

The cohorts of oocytes obtained after LPS are larger than their paired-FPS-derived cohorts and show a comparable competence, thus resulting in a larger mean number of blastocysts.

WHAT IS KNOWN ALREADY

Three theories of follicle recruitment have been postulated to date: (i) the ‘continuous recruitment’ theory, (ii) the ‘single recruitment episode’ theory and (iii) the ‘wave’ theory. Yet, a clear characterization of this crucial biological process for human reproduction is missing. Recent advances implemented in in vitro fertilization (IVF), such as blastocyst culture, aneuploidy testing and vitrification, have encouraged clinicians to maximize the exploitation of the ovarian reserve through tailored stimulation protocols, which is crucial especially for poor prognosis patients aiming to conceive after IVF. LPS has been already successfully adopted to treat poor prognosis or oncological patients through Duostim, LPS-only or random-start ovarian stimulation approaches. Nevertheless, little, and mainly retrospective, evidence has been produced to support the safety of LPS in general. Feasibility of the LPS approach would severely question the classic ‘single recruitment episode’ theory of follicular development.

STUDY DESIGN, SIZE, DURATION

This case-control study was conducted with paired follicular phase- and luteal phase-derived cohorts of oocytes collected after stimulations in the same ovarian cycle (DuoStim) at two private IVF clinics between October 2015 and December 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included 188 poor prognosis patients undergoing DuoStim with preimplantation genetic testing for aneuploidies (PGT-A). FPS and LPS were performed with the same daily dose of recombinant-gonadotrophins in an antagonist protocol. Blastocyst culture, trophectoderm biopsy, vitrification and frozen-warmed euploid single blastocyst transfers were performed. The primary outcome was the mean number of blastocysts obtained per oocyte retrieval from paired-FPS- and LPS-derived cohorts (required sample size = 165 patients; power = 90%). Mean blastulation and euploidy rates were monitored, along with the number of oocytes, euploid blastocysts and clinical outcomes.

MAIN RESULTS AND THE ROLE OF CHANCE

Significantly fewer blastocysts were obtained after FPS than LPS (1.2 ± 1.1 vs. 1.6 ± 1.6, P < 0.01), due to fewer oocytes collected (3.6 ± 2.1 vs. 4.3 ± 2.8, P < 0.01) and a similar mean blastocyst rates per retrieval (33.1% ± 30.3% vs. 37.4% ± 30.8%, P = NS). The number of oocytes collected were correlated (R = 0.5, P < 0.01), while the blastocyst rates were uncorrelated among paired-FPS- and LPS-derived cohorts. Overall, a significantly lower chance of producing blastocyst(s) was reported after FPS than after LPS: 67.6% (n = 127/188, 95%CI: 60.3–74.1) vs. 77.1% (n = 145/188, 95%CI: 70.3–82.8; P = 0.05). The mean euploidy rates per retrieval were similar between FPS- and LPS-derived cohorts of oocytes (13.6% ± 22.8% vs. 16.3% ± 23.4%, P = NS). Therefore, on average fewer euploid blastocysts (0.5 ± 0.8 vs. 0.7 ± 1.0, P = 0.02) resulted from FPS. Similar ongoing-pregnancy/delivery rates were reported, to date, after FPS- and LPS-derived euploid single blastocyst transfers: 42.4% (n = 28/66, 95%CI: 30.5–55.2) vs. 53.8% (n = 35/65, 95%CI: 41.1–66.1; P = NS).

LIMITATIONS, REASONS FOR CAUTION

More studies need to be conducted in the future to confirm the safety of LPS, especially in terms of ovarian and follicular environment, as well as the clinical, peri-natal and post-natal outcomes. Here, we showed preliminary data suggesting a similar ongoing implantation/delivery rate (>22 weeks) between FPS- and LPS-derived euploid blastocysts, that need to be extended in the future, to populations other than poor prognosis patients and using approaches other than DuoStim together with a constant monitoring of the related peri-natal and post-natal outcomes.

WIDER IMPLICATIONS OF THE FINDINGS

These data, from a paired study design, highlight that LPS-derived oocytes are as competent as FPS-derived oocytes, thereby adding some evidence to support the use of LPS for poor prognosis and oncological patients and to question the ‘single recruitment episode’ theory of follicle recruitment. These findings also encourage additional studies of the basics of folliculogenesis, with direct clinical implications for the management of ovarian stimulation in IVF.

TRIAL REGISTRATION

None.

STUDY FUNDING/COMPETING INTEREST(S)

No external funds were used for this study and there are no conflicts of interest.

Placental histopathology in IVF pregnancies resulting from the transfer of frozen-thawed embryos compared with fresh embryos

PURPOSE

To study whether placentas of singleton pregnancies conceived after fresh embryo transfer (ET) contain more histopathological lesions compared with placentas of singleton pregnancies conceived after frozen-thawed embryo transfer (FET).

METHODS

A prospective cohort study of placental histopathology in 131 women with singleton IVF pregnancies who delivered at a single medical center, between December 2017 and May 2019. The prevalence of different placental histopathology lesions was compared between women who conceived after fresh ET and FET.

RESULTS

Women who conceived after fresh ET (n = 74) did not differ from women who conceived after FET (n = 57) with regard to maternal age, BMI, nulliparity, or infertility diagnosis. Gestational week at delivery was lower in pregnancies conceived after fresh ET (38.5 vs. 39.2 weeks, respectively, p = 0.04), and a trend for a lower birthweight following fresh ET was noted (3040 vs. 3216 g, respectively, p = 0.053). However, placental histopathology analysis from pregnancies conceived after fresh ET was comparable to pregnancies conceived after FET, with regard to the prevalence of maternal vascular malperfusion lesions (45.9% vs. 50.9%, respectively, p = 0.57), fetal vascular malperfusion lesions (17.6% vs. 21.1, p = 0.61), acute inflammatory response lesions (28.4% vs. 28.1%, respectively, p = 0.96), and chronic inflammatory response lesions (13.5% vs. 8.8%, respectively, p = 0.48).

CONCLUSION

Placental histopathology did not differ between IVF pregnancies conceived after fresh and frozen ET. These results are reassuring for clinicians and patients who wish to pursue with transferring fresh embryos.

Modulation of P2Y2 receptors in bovine cumulus oocyte complexes: effects on intracellular calcium, zona hardening and developmental competence

The improvement of cryopreserved oocyte survival is imperative for the preservation of female fertility. In this study, we investigate whether P2Y2 receptors (P2Y2R) can be directly implicated in calcium (Ca²⁺) homeostasis misbalances observed during the cryopreservation process of cumulus oocyte complexes (COC). Firstly, RNA was extracted from bovine immature and mature oocytes and cumulus cells and real-time PCR performed to identify P2Y2R transcripts (experiment 1). Changes in intracellular calcium concentration [Ca2+]i of mature COC and oocytes (experiment 2) were measured upon exposure to cryoprotectants (CPA), UTP (P2Y2R stimulator, 100 μM), and/or suramin (P2Y2R inhibitor, 100 and 300 μM). The functional role of P2Y2R was investigated by analyzing the effect on oocyte viability of its modulation prior and during oocyte exposure to CPA (experiment 3). Mature COC were randomly divided into groups, and exposed to CPA and different P2Y2 modulators. Oocytes' viability, cortical granules location, and competence for development were assessed. Results showed that P2Y2R mRNAs are expressed in both oocytes and cumulus cells. Stimulation with UTP and CPA led to [Ca2+]i increase, and this effect was totally or partially blocked by suramin (P2Y2R inhibitor). Oocyte exposure to CPA and UTP reduced embryo rates compared with control and suramin100μM (P ≤ 0.04). The observed enhanced premature zona hardening in oocytes exposed to CPA (P = 0.04) and UTP (P = 0.005) stimulus was inhibited by suramin 100 μM. In conclusion, inhibition of P2Y2R during cryoprotectant exposure reduces premature intracellular Ca²⁺ release and significantly improves the developmental competence of exposed bovine oocytes.

A tale of two studies: now is no longer the best of times for preimplantation genetic testing for aneuploidy (PGT-A)

Preimplantation genetic testing for aneuploidy (PGT-A) does not create normal embryos, but selecting a viable embryo for a fresh transfer has the potential to deliver an extra effect for live birth from a stimulated cycle by evading the attrition associated with embryo cryopreservation. Improved genetic tests are now available for selecting viable embryos; however, current embryo cryopreservation techniques also have a superior survival rate, which means it is now possible to transfer most morphologically suitable embryos from a stimulated cycle one at a time. The cumulative live birth rate from a stimulated cycle is now unlikely to be superior compared with morphological assessment alone, with any benefit likely to be associated with a reduction in the risk of miscarriage and the time to pregnancy. This communication offers a perspective on the likely benefit and disbenefit of PGT-A based on the outcome of modern-day clinical studies. Caution should be advised regarding offering PGT-A to every woman. Quantifying the likely miscarriage benefit and live birth disbenefit for an appropriate patient group may help to better inform couples who might be considering adding aneuploidy screening to their treatment cycle.

Frozen-thawed embryo transfer: the potential importance of the corpus luteum in preventing obstetrical complications

The use of frozen-thawed embryo transfer (FET) has increased over the past decade with improvements in technology and increasing live birth rates. FET facilitates elective single-embryo transfer, reduces ovarian hyperstimulation syndrome, optimizes endometrial receptivity, allows time for preimplantation genetics testing, and facilitates fertility preservation. FET cycles have been associated, however, with an increased risk of hypertensive disorders of pregnancy for reasons that are not clear. Recent evidence suggests that absence of the corpus luteum (CL) could be at least partly responsible for this increased risk. In a recent prospective cohort study, programmed FET cycles (no CL) were associated with higher rates of preeclampsia and preeclampsia with severe features compared with modified natural FET cycles. FET cycles are commonly performed in the context of a programmed cycle in which the endometrium is prepared with the use of exogenous E2 and P. In these cycles, ovulation is suppressed and therefore the CL is absent. The CL produces not only E2 and P, but also vasoactive products, such as relaxin and vascular endothelial growth factor, which are not replaced in a programmed FET cycle and which are hypothesized to be important for initial placentation. Emerging evidence has also revealed other adverse obstetrical and perinatal outcomes, including postpartum hemorrhage, macrosomia, and post-term birth specifically in programmed FET cycles compared with natural FET cycles. Despite the widespread use of FET, the optimal protocol with respect to live birth rate, maternal health, and perinatal outcomes has yet to be determined. Future practice regarding FET should be based on high-quality evidence, including rigorous controlled trials.

Effect of Maternal Age on Pregnancy or Neonatal Outcomes Among 4,958 Infertile Women Using a Freeze-All Strategy

The freeze-all strategy has been increasingly employed in the context of in vitro fertilization (IVF) cycles globally, but the relative advantages of this approach are not entirely understood. Herein we sought to assess how maternal age affected pregnancy and neonatal outcomes in women who had undergone frozen–thawed embryo transfer (FET). In this retrospective analysis, we assessed outcomes for 4,958 total women at the University-affiliated Tertiary Centre from January—December 2017. We compared pregnancy and neonatal outcomes between a control group (<30 years old) and groups of more advanced maternal age (30–34, 35–37, 38–40, 41–43, and 44–50 years). We found that live birth rates (LBR) for the first FET cycle following a freeze-all strategy significantly declined with increasing maternal age, with the most pronounced declines in the 35–37 and 38–40 age groups (LBR: 51.12% at <30 years, 43.86% at 30–34 years, 41.64% at 35–37 years, 25.67% at 38–40 years, 15.58% at 40–43 years, and 4.78% at 44–50 years, respectively). Rates of preterm delivery (PTD), very PTD, low birth weight (LBW), very LBW, term LBW, preterm LBW, and macrosomia were comparable across study groups. Together these results thus suggest that increasing maternal age has an adverse impact on pregnancy outcomes without affecting PTD or LBW risk in the context of a freeze-all strategy.

Human oocytes and zygotes are ready for ultra-fast vitrification after 2 minutes of exposure to standard CPA solutions

Vitrification of human oocytes and embryos in different stages of development is a key element of daily clinical practice of in vitro fertilization treatments. Despite the cooling and warming of the cells is ultra-fast, the procedure as a whole is time consuming. Most of the duration is employed in a long (8–15 minutes), gradual or direct exposure to a non-vitrifying cryoprotectant solution, which is followed by a short exposure to a more concentrated vitrifying solution. A reduction in the duration of the protocols is desirable to improve the workflow in the IVF setting and reduce the time of exposure to suboptimal temperature and osmolarity, as well as potentially toxic cryoprotectants. In this work it is shown that this reduction is feasible. In silico (MatLab program using two-parameter permeability model) and in vitro observations of the oocytes’ osmotic behaviour indicate that the dehydration upon exposure to standard cryoprotectant solutions occurs very fast: the point of minimum volume of the shrink-swell curve is reached within 60 seconds. At that point, intracellular water ejection is complete, which coupled with the permeation of low molecular weight cryoprotectants results in similar intracellular and extracellular solute concentrations. This shows that prolonging the exposure to the cryoprotectant solutions does not improve the cytosolic glass forming tendency and could be avoided. To test this finding, human oocytes and zygotes that were donated for research were subjected to a shortened, dehydration-based protocol, consisting of two consecutive exposures of one-minute to two standard cryoprotectant solutions, containing ethylene glycol, dimethyl sulfoxide and sucrose. At the end of this two-minute dehydration protocol, the critical intracellular solute concentration necessary for successful vitrification was attained, confirmed by the post-warming survival and ability to resume cytokinesis of the cells. Further studies of the developmental competency of oocytes and embryos would be necessary to determine the suitability of this specific dehydration protocol for clinical practice, but based on our results, short times of exposure to increasingly hypertonic solutions could be a more time-efficient strategy to prepare human oocytes and embryos for vitrification.

A monocentric analysis of the efficacy of extracellular cryoprotectants in unfrozen solutions for cleavage stage embryos

BACKGROUND

In the absence of international guidelines indicating the usage of vitrification rather than slow-freezing, the study aim was to analyze a large cohort of slow-frozen/thawed embryos to produce a rationale supporting the standardization of IVF cryopreservation policy.

METHODS

This retrospective analysis included 4779 cleavage stage embryos cryopreserved by slow-freezing/thawing from September 2009 to April 2017 at a single Center. Biological and clinical outcomes of three different commercial kits adopted sequentially, i.e. Vitrolife Cleave Kit® from Vitrolife (kit 1) vs. K-SICS-5000 Kit® and K-SITS-5000 Kit® from Cook Medical (kit 2) and Freeze/Thaw 1™ Kit® from Vitrolife (kit 3) were collected and compared in the light of cryoprotectants composition.

RESULTS

Kit 3 compared to kit 1 and kit 2 showed significantly (P < 0.001) higher embryo survival (79.9% vs. 75.6 and 68.1%, respectively) and frozen embryo replacement (91.5% vs. 86.5 and 83.3%, respectively) rates, and significantly (P < 0.001) lower blastomere degeneration rate (41.5% vs. 43.6 and 52.4%, respectively). No significant difference for clinical outcomes was observed among kits. Only a slight positive trend was observed for kit 3 vs. kit 1 and kit 2 on delivery rate per thawing cycle (7.12% vs. 4.19 and 4.51%, respectively; P < 0.058) and live birth rate (3.07% vs. 2.59 and 1.93%, respectively, P < 0.069). Thawing solutions of kit 3 were similar to those of any warming protocol.

CONCLUSIONS

A defined concentration of extracellular cryoprotectants in thawing/warming solutions had a beneficial effect on the embryo cryosurvival rate. Results could provide the rationale for the adoption of a single standardized warming protocol.

Day 5 versus Day 6 blastocyst transfers: a systematic review and meta-analysis of clinical outcomes

STUDY QUESTION

Is there a difference in clinical pregnancy and live birth rates (LBRs) between blastocysts developing on Day 5 (D5) and blastocysts developing on Day 6 (D6) following fresh and frozen transfers?

SUMMARY ANSWER

D5 blastocyst transfers (BTs) present higher clinical pregnancy and LBRs than D6 in both fresh and frozen transfers.

WHAT IS KNOWN ALREADY

BT is increasingly popular in assisted reproductive technology (ART) centers today. To our knowledge, no meta-analysis has focused on clinical outcomes in both fresh and frozen BT. Concerning frozen blastocysts, one meta-analysis in 2010 found no significant difference in pregnancy outcomes between D5 and D6 BT. Since then, ART practices have evolved particularly with the wide use of vitrification, and more articles comparing D5 and D6 BT cycles have been published and described conflicting results.

STUDY DESIGN, SIZE, DURATION

Systematic review and meta-analysis of published controlled studies. Searches were conducted from 2005 to February 2018 on MEDLINE and Cochrane Library and from 2005 to May 2017 on EMBASE, Eudract and clinicaltrials.gov, using the following search terms: blastocyst, Day 5, Day 6, pregnancy, implantation, live birth and embryo transfer (ET).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 47 full-text articles were preselected from 808 references, based on title and abstract and assessed utilizing the Newcastle-Ottowa Quality Assessment Scales. Study selection and data extraction were carried out by two independent reviewers according to Cochrane methods. Random-effect meta-analysis was performed on all data (overall analysis) followed by subgroup analysis (fresh, vitrified/warmed, slow frozen/thawed).

MAIN RESULTS AND THE ROLE OF CHANCE

Data from 29 relevant articles were extracted and integrated in the meta-analysis. Meta-analysis of the 23 studies that reported clinical pregnancy rate (CPR) as an outcome, including overall fresh and/or frozen ET cycles, showed a significantly higher CPR following D5 ET compared with D6 ET (risk ratio (RR) = 1.27, 95% CI: 1.15-1.39, P < 0.001). For CPR, calculated subgroup RRs were 2.38 (95% CI: 1.74-3.24, P < 0.001) for fresh BT; 1.27 (95% CI: 1.16-1.39, P < 0.001) for vitrified/warmed BT; and 1.15 (95% CI: 0.93-1.41, P = 0.20) for slow frozen/thawed BT. LBR was also significantly higher after D5 BT (overall RR = 1.50 (95% CI: 1.32-1.69), P < 0.001). The LBR calculated RRs for subgroups were 1.74 (95% CI: 1.37-2.20, P < 0.001) for fresh BT; 1.38 (95% CI: 1.23-1.56, P < 0.001) for vitrified/warmed BT; and 1.44 (95% CI: 0.70-2.96, P = 0.32) for slow frozen/thawed BT. Sensitivity analysis led to similar results and conclusions: CPR and LBR were significantly higher following D5 compared to D6 BT.

LIMITATIONS, REASONS FOR CAUTION

The validity of meta-analysis results depends mainly on the quality and the number of the published studies available. Indeed, this meta-analysis included no randomized controlled trial (RCT). Slow frozen/thawed subgroups showed substantial heterogeneity.

WIDER IMPLICATIONS OF THE FINDINGS

In regards to the results of this original meta-analysis, ART practitioners should preferably transfer D5 rather than D6 blastocysts in both fresh and frozen cycles. Further RCTs are needed to address the question of whether D6 embryos should be transferred in a fresh or a frozen cycle.

STUDY FUNDING/COMPETING INTEREST(S)

This work was sponsored by an unrestricted grant from GEDEON RICHTER France. The authors have no competing interests to declare.

REGISTRATION NUMBER

CRD42018080151.

[Causes of oocyte vitrification and its value in assisted reproductive technology]

OBJECTIVE

To explore the causes of oocyte vitrification and its application in assisted reproduction.

METHODS

We retrospectively analyzed the data of 26 patients with 27 cycles of oocyte vitrification cryopreservation undergoing intracytoplasmic sperm injection (ICSI) and embryo transfer between January, 2008 and October, 2018. The causes of oocyte vitrification and the outcomes of ICSI and clinical pregnancy were analyzed.

RESULTS

The causes of oocytes vitrification included mainly azoospermia or severe spermatogenesis disorder of the husband, failure to obtain sperms from the husband, failure of the husband to be present on the day of oocyte retrieval and acute diseases of the husband to not allow sperm collection. A total of 274 oocytes were frozen in 27 oocyte retrieval cycles, and 217 eggs were thawed in 19 cycles with a survival rate of 81.11% (176/217). The normal fertilization rate, cleavage rate and high-quality embryo rate was 74.81% (98/131), 89.80% (88/98) and 36.73% (36/98), respectively. Fifteen patients underwent embryo transfer, and the clinical pregnancy rate and live birth rate was 53.33% (8/15) and 33.33% (5/15), respectively. Compared with patients below 35 years of age, the patients aged above 35 years had significantly lower oocyte survival rate after thawing (82.76% vs 74.42%, P=0.211), clinical pregnancy rate (77.78% vs 16.67%, P=0.041) and live birth rate (55.56% vs 0, P=0.044).

CONCLUSIONS

Oocytes vitrification can be used as a remedy for infertile couples who fail to provide sperms due to male factors on the day of oocyte retrieval. Vitrification of the oocytes does not significantly affect the fertilization rate or the clinical pregnancy rate. The survival rate of the thawed oocytes is related to the age of the wife, and an age younger than 35 years can be optimal for achieving favorable clinical pregnancy outcomes after oocyte vitrification.

Contribution of cryopreservation to the cumulative live birth rate: a large multicentric cycle-based data analysis from the Italian National Registry

PURPOSE

To estimate the contribution of cryopreservation to the cumulative live birth rate (CLBR) after law modification in Italy in the era of vitrification and freeze-all.

METHODS

The Italian National Registry performed a cycle-based data collection. Nine Italian IVF clinics were involved incorporating a total of 10,260 fresh cycles performed between January 2015 and April 2016 resulting in 9273 oocyte retrievals and 3266 subsequent warming cycles from the same oocyte retrievals performed up to December 2016. Mean female age was 37 ± 4.3 years. Primary outcome measure was CLBR per oocyte retrieval. Confounding factors were tested in multivariate regression analysis, and the relative impact of cryopreservation to the CLBR in different patient categories was calculated.

RESULTS

CLBR per oocyte retrieval was 32.6%, 26.5%, 18.7%, 13.0%, and 5.5% for women younger than 36, aged 36-39, 40-41, and older than 41 years, respectively. The total relative contribution of oocyte/embryo cryopreservation was 40.6% (95% CI 38.41-42.75). An association between maternal age, number of oocytes retrieved, fertilization rate, cryopreservation, and cumulative live birth was shown. When adjusted for confounders, a 2.3-fold increase was observed in the chance of live birth when cryopreservation was performed (OR 2.3; 95% CI 1.99-2.56). In high responder patients (> 15 oocytes retrieved) where freeze-all was applied in 67.6% of cycles to avoid the risk of hyper stimulation syndrome, the relative contribution of vitrification to the CLBR was 80.6%.

CONCLUSIONS

Cryopreservation is essential in IVF and should always be available to patients to optimize success rates. Multicentric, cycle-based data analyses are crucial to provide infertile couples, clinicians, and regulatory bodies with accurate information on IVF effectiveness including fresh and cryopreserved cycles.

Embryo donation: Survey of in-vitro fertilization (IVF) patients and randomized trial of complimentary counseling

Design

This study surveyed patients with stored frozen embryos and developed and tested an intervention through a randomized trial to support subjects to consider embryo disposition options (EDOs), especially donation for family building.

Methods

Based on a review of literature on EDOs, the authors developed and mailed a 2-page anonymous survey to 1,053 patients in Massachusetts (USA) to elicit their feelings about their stored embryos. Target patients had embryos cryopreserved for ≥1 year and had not indicated an EDO. Survey respondents were next randomized between usual care (control arm) or an offer of complimentary counseling and educational support regarding EDOs. These counseling sessions were conducted by a licensed mental health professional specializing in infertility treatment.

Results

Despite telephone reminders, only 21.3% of patients responded, likely reflecting most patients’ reluctance to address EDOs. Respondents endorsed an average of 2 of the 5 EDOs, with the following percentages supporting each option: store for future attempts (82%), continue storage (79%), donate to research (29%), discard (14%), and donate for family building (13%). When asked their opinions towards embryo donation to another couple, 78% of patients agreed that donation is a way to help another couple, 48% would consider embryo donation to another family if they had a better understanding of the process, and 38% would be willing to consider donation if they were not going to use the embryos themselves, but 73% expressed discomfort with donation. In the randomized trial, 7.8% of intervention subjects (n = 8) obtained counseling sessions compared to 0.0% (none) of usual care subjects (p = 0.0069). Counseling participants valued not only discussing EDOs, but also assistance in expressing their feelings and differences with their partners.

Conclusion

Improvement in counseling rates over the control arm suggests that free professional counseling is a small, but likely effective, step towards deciding on an EDO.

ClinicalTrials.gov Identifier: NCT01883934 (Frozen embryo donation study).

Role of stem cells in fertility preservation: current insights

While improvements made in the field of cancer therapy allow high survival rates, gonadotoxicity of chemo- and radiotherapy can lead to infertility in male and female pre- and postpubertal patients. Clinical options to preserve fertility before starting gonadotoxic therapies by cryopreserving sperm or oocytes for future use with assisted reproductive technology (ART) are now applied worldwide. Cryopreservation of pre- and postpubertal ovarian tissue containing primordial follicles, though still considered experimental, has already led to the birth of healthy babies after autotransplantation and is performed in an increasing number of centers. For prepubertal boys who do not produce gametes ready for fertilization, cryopreservation of immature testicular tissue (ITT) containing spermatogonial stem cells may be proposed as an experimental strategy with the aim of restoring fertility. Based on achievements in nonhuman primates, autotransplantation of ITT or testicular cell suspensions appears promising to restore fertility of young cancer survivors. So far, whether in two- or three-dimensional culture systems, in vitro maturation of immature male and female gonadal cells or tissue has not demonstrated a capacity to produce safe gametes for ART. Recently, primordial germ cells have been generated from embryonic and induced pluripotent stem cells, but further investigations regarding efficiency and safety are needed. Transplantation of mesenchymal stem cells to improve the vascularization of gonadal tissue grafts, increase the colonization of transplanted cells, and restore the damaged somatic compartment could overcome the current limitations encountered with transplantation.

The main will of the patients of a private Italian IVF clinic for their aneuploid/affected blastocysts would be donation to research: a currently forbidden choice

PURPOSE

Surplus cryopreserved affected/aneuploid blastocysts may be obtained after in vitro fertilization (IVF) treatments with preimplantation genetic testing (PGT). These embryos are considered not suitable for transfer and may be discarded. Currently, in Italy, an embryo disposition decision (EDD) is not allowed and the frozen/vitrified blastocysts (even if affected/aneuploid) should be kept cryopreserved indefinitely. In this peculiar clinical, social, and legislative scenario, we aimed at assessing the attitudes of the patients towards the fate of these embryos, in case the local regulation would be changed and allow an EDD regarding the surplus affected/aneuploid embryos obtained after PGT.

METHODS

A questionnaire with multiple answers was submitted to 832 patients who obtained affected/aneuploid embryos during a PGT cycle at our private IVF center. They were asked to choose between three putative options with related reasons: everlasting cryopreservation (only option currently available); discard or donate them to research.

RESULTS

Overall, 149 patients (18%; 85 women and 64 men) answered the questionnaire. Among them, 84% (n = 126) would choose to donate their affected/aneuploid blastocysts to research, 9% (n = 13) would discard them and only 7% (n = 10) would keep them cryopreserved indefinitely.

CONCLUSIONS

Donation of the affected/aneuploid blastocysts is the option chosen from most of the respondents (84%; 15% of the eligible patients). These patients are motivated from the altruistic will of incentivating the progress in IVF and/or stem cell research and supporting future couples to limit/solve their infertility/health issues.

Child Health: Is It Really Assisted Reproductive Technology that We Need to Be Concerned About?

Concerns remain about the health of children conceived by infertility treatment. Studies to date have predominantly not identified substantial long-term health effects after accounting for plurality, which is reassuring given the increasing numbers of children conceived by infertility treatment worldwide. However, as technological advances in treatment arise, ongoing studies remain critical for monitoring health effects. To study whether the techniques used in infertility treatment cause health differences, however, remains challenging due to identification of an appropriate comparison group, heterogeneous treatment, and confounding by the underlying causes of infertility. In fact, the factors that are associated with underlying infertility, including parental obesity and other specific male and female factors, may be important independent factors to consider. This review will summarize key methodological considerations in studying children conceived by infertility treatment including the evidence of associations between underlying infertility factors and child health.

RHOA activity in expanding blastocysts is essential to regulate HIPPO-YAP signaling and to maintain the trophectoderm-specific gene expression program in a ROCK/actin filament-independent manner

STUDY QUESTION

What molecular signals are required to maintain the functional trophectoderm (TE) during blastocyst expansion of the late stage of preimplantation development?

SUMMARY ANSWER

The activity of ras homology family member A (RHOA) GTPases is necessary to retain the expanded blastocyst cavity and also to sustain the gene expression program specific to TE.

WHAT IS KNOWN ALREADY

At the early stages of preimplantation development, the precursor of the TE lineage is generated through the molecular signals that integrate RHOA, RHO-associated coiled-coil containing protein kinase (ROCK), the apicobasal cell polarity, and the HIPPO-Yes-associated protein (YAP) signaling pathway. By contrast, molecular mechanisms regulating the maintenance of the TE characteristics at the later stage, which is crucial for blastocyst hatching and implantation, are scarcely understood.

STUDY DESIGN, SIZE, DURATION

Expanding mouse blastocysts, obtained from crosses of the F1 (C57BL6 × DBA/2) strain, were exposed to chemical agents that interfere with RHOA, ROCK, or the actin cytoskeleton for up to 8 h, and effects on the blastocyst cavity, HIPPO-YAP signaling, and cell lineage-specific gene expression profiles were examined.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Mouse embryos at the embryonic stage E3.5 (expanding blastocysts) and E4.5 (fully expanded blastocysts) were treated with RHOA inhibitor (C3 exoenzyme), ROCK inhibitor (Y27632), or actin filament disruptors (cytochalasin B and latrunculin A). The integrity of the blastocyst cavity was evaluated based on the gross morphology. Effects on HIPPO-YAP signaling were assessed based on the presence of nuclearized YAP protein by immunofluorescence staining and the expression of YAP/TEA domain family member (TEAD) target genes by quantitative RT-PCR (qRT-PCR). The impact of these disruptors on cell lineages was evaluated based on expression of the TE-specific and inner cell mass-specific marker genes by qRT-PCR. The integrity of the apicobasal cell polarity was assessed by localization of protein kinase C zeta (PRKCZ; apical) and scribbled planar cell polarity (SCRIB; basal) proteins by immunofluorescence staining. For comparisons, cultured cell lines, NIH/3T3 (mouse fibroblast) and P19C5 (mouse embryonal carcinoma), were also treated with RHOA inhibitor, ROCK inhibitor, and actin filament disruptors for up to 8 h, and effects on HIPPO-YAP signaling were assessed based on expression of YAP/TEAD target genes by qRT-PCR. Each experiment was repeated using three independent batches of embryos (n = 40-80 per batch) or cell collections. Statistical analyses of data were performed, using one-way ANOVA and two-sample t-test.

MAIN RESULTS AND THE ROLE OF CHANCE

Inhibition of RHOA deflated the cavity, diminished nuclear YAP (P < 0.01), and down-regulated the YAP/TEAD target and TE-specific marker genes in both E3.5 and E4.5 blastocysts (P < 0.05), indicating that the maintenance of the key TE characteristics is dependent on RHOA activity. However, inhibition of ROCK or disruption of actin filament only deflated the blastocyst cavity, but did not alter HIPPO-YAP signaling or lineage-specific gene expressions, suggesting that the action of RHOA to sustain the TE-specific gene expression program is not mediated by ROCK or the actomyosin cytoskeleton. By contrast, ROCK inhibitor and actin filament disruptors diminished YAP/TEAD target gene expressions in cultured cells to a greater extent than RHOA inhibitor, implicating that the regulation of HIPPO-YAP signaling in expanding blastocysts is distinctly different from that in the cell lines. Furthermore, the apicobasal cell polarity proteins in the expanding blastocyst were mislocalized by ROCK inhibition but not by RHOA inhibition, indicating that cell polarity is not linked to regulation of HIPPO-YAP signaling. Taken together, our study suggests that RHOA activity is essential to maintain the TE lineage in the expanding blastocyst and it regulates HIPPO-YAP signaling and the lineage-specific gene expression program through mechanisms that are independent of ROCK or actomyosin cytoskeleton.

LARGE-SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

This study was conducted using one species, the mouse. Direct translation of the experiments and findings to human fertility preservation and ART requires further investigations.

WIDER IMPLICATIONS OF THE FINDINGS

The elucidation of the mechanisms of TE formation is highly pertinent to fertility preservation in women. Our findings may raise awareness among providers of ART that the TE is sensitive to disturbance even in the late stage of blastocyst expansion and that rational approaches should be devised to avoid conditions that may impair the TE and its function.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by grants from the Ingeborg v.F. McKee Fund of the Hawaii Community Foundation (16ADVC-78882 to V.B.A.), and the National Institutes of Health (P20 GM103457 and R03 HD088839 to V.B.A.). The authors have no conflict of interest to declare.

N-acetylcysteine addition after vitrification improves oocyte mitochondrial polarization status and the quality of embryos derived from vitrified murine oocytes

Background

Vitrification is the safest method to cryopreserve oocytes, however the process alters mitochondrial function resulting from increased reactive oxygen species (ROS) production. Our aim was to alleviate ROS stress in vitrified mice oocytes using N-acetylcysteine (NAC at 1 mM), to improve the oocyte’s developmental competence.

Results

Hence, four experimental groups were compared: fresh oocytes (F-C), vitrified oocytes (V-C), NAC addition prior to oocyte vitrification (V-NAC-Pre) and NAC addition after vitrification (V-NAC-Post). V-NAC-Pre and V-NAC-Post exhibited higher levels of mitochondrial polarization compared to vitrified oocytes (36.5 ± 3.1, 37.7 ± 1.3 and 27.2 ± 2.4 measured as the spatial coefficient of variation/oocyte respectively, mean ± SEM; p < 0.05). However, ROS production increased in vitrified oocytes added with NAC compared to the vitrified control (1124.7 ± 102.1 [V-NAC-Pre] and 1063.2 ± 82.1 [V-NAC-Post] vs. 794.6 ± 164.9 [V-C]; arbitrary fluorescence units/oocyte, mean ± SEM; p < 0.05). ATP significantly decreased in V-NAC-Pre compared to V-NAC-Post oocytes (18.5 ± 6.9 vs. 54.2 ± 4.6 fmol/oocyte respectively, mean ± SEM; p < 0.05), and no differences were observed between V-NAC-Post, F-C and V-C groups. Blastocyst rates derived from F-C oocytes was higher than those derived from V-NAC-Pre (90.7 ± 1.8 vs. 79.1 ± 1.8, respectively, mean % ± SEM,; p < 0.05) but similar to those derived from V-NAC-Post (90.7 ± 1.8, mean % ± SEM, p > 0.05). Total blastomere count of blastocysts derived from V-NAC-Post after in vitro fertilization (IVF) was higher than embryos produced from V-C.

Conclusions

The addition of NAC after vitrification improves the quality of vitrified mature murine oocytes while its addition prior to vitrification is advised against.

Cumulus-corona gene expression analysis combined with morphological embryo scoring in single embryo transfer cycles increases live birth after fresh transfer and decreases time to pregnancy

PURPOSE

Clinical pregnancy rate after IVF with eSET stagnates between 30 and 40%. In order to increase pregnancy and live birth rates, multiple embryo transfer is still common practice. Providing additional non-invasive tools to choose the competent embryo for transfer could avoid multiple pregnancy and improve time to pregnancy. Cumulus mRNA analysis with quantitative PCR (QPCR) is a non-invasive approach. However, so far, no gene sets have been validated in prospective interventional studies.

METHODS

A prospective interventional single-center pilot study with two matched controls (day-3 and day-5 eSET) was performed in 96 patients consenting to the analysis of the cumulus-corona of their oocytes. All patients were super-ovulated for ICSI and eSET at day 3. All oocytes were denuded individually and cumulus was analyzed by quantitative PCR using three predictive genes (EFNB2, SASH1, CAMK1D) and two housekeeping genes (UBC and β2M). Patients (n = 62) with 2 or more day-3 embryos (good or excellent morphology) had their embryo chosen following the normalized expression of the genes.

RESULTS

Corona testing significantly increased the clinical pregnancy and live births rates (63% and 55%) compared to single embryo transfer (eSET) on day 3 (27% and 23%: p < 0.001) and day 5 (43% and 39%: p = 0.022 and p = 0.050) fresh transfer cycle controls with morphology-only selection. Time-to-pregnancy was significantly reduced, regardless of the number of good-quality embryos available on day 3.

CONCLUSION

Combining standard morphology scoring and cumulus/corona gene expression analysis increases day-3 eSET results and significantly reduces the time to pregnancy.

TRIAL REGISTRATION NUMBER

This is not an RCT study and was only registered by the ethical committee of the University Hospital UZBRUSSEL of the Vrije Universiteit Brussel VUB (BUN: 143201318000).

Fertility Preservation in Benign Gynecological Diseases: Current Approaches and Future Perspectives

Although fertility preservation is a growing topic in the management of oncological diseases, different benign gynecological pathologies are able to compromise the ovarian reserve due to mechanisms related to the pathology itself or secondary to the performed treatments. Endometriosis, benign ovarian tumors, adnexal torsion, familiarity and genetic syndromes are all benign conditions that can compromise the ovarian reserve. Endometriosis and particularly endometriomas provide a direct damage to ovarian reserve, with different mechanisms, and an indirect damage related to surgery. Similarly, benign ovarian tumors can provide a detrimental effect on ovarian reserve for the surgical treatment, especially for bilateral or recurrent tumors, and in case of secondary adnexal torsion with late diagnosis. Different fertility preservation options are available and should be considered particularly in cases with bilateral or recurrent pathology and/or surgery. In general, the identification of patients at risk of early ovarian failure, for benign gynecological disease or based on known genetic causes or familiarity, is of paramount importance in order to apply fertility preservation techniques before the complete depletion of ovarian reserve.

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.

Oocyte Cryopreservation in Oncological Patients: Eighteen Years Experience of a Tertiary Care Referral Center

Objective: The aim of the present study is to report our experience on elective women fertility preservation before cancer treatment. Study Design: This is a single-center retrospective observational study, including all patients who underwent elective fertility preservation before oncological treatment between January 2001 and March 2019 at our Institute. Results: Of a total of 568 women who received fertility counseling, 244 (42.9%) underwent 252 oocyte retrieval cycles after controlled ovarian stimulation for cryopreservation. The majority of patients were diagnosed with breast cancer (59.9%), followed by women affected by Hodgkin's and non-Hodgkin's lymphoma (27.4%). A minority comprised patients diagnosed with other malignancies that affected soft tissues (2.8%), ovary borderline type (2.4%), digestive system (1.6%), leukemia (1.6%), uterine cervix (1.2%). The remaining 3.1% were affected by other cancer types. The mean age of the cohort was 31.3 ± 6.4 years and the mean oocyte retrieval was 13.5± 8.4. Of 11 women who returned to attempt a pregnancy, three performed two thawed cycles. We obtained four pregnancies from 24 embryo transfers (Pregnancy Rate 36.4% for couple): two miscarriages and two live births. Overall, 95.7% of oocytes are still in storage. Conclusions: A close collaboration between Cancer and Fertility Center in a tertiary care hospital is essential to provide a good health service in oncological patients. Offering fertility preservation is no longer considered optional and must be included in every therapeutic program for women who receive an oncological diagnosis in their reproductive age. Oocyte cryopreservation appears to be a good opportunity for fertility preservation. Our results, although they are obtained in a small sample, are encouraging, even if only 4.5% of patients returned to use their gametes.

Comparison of Conventional Slow Freeze versus Permeable Cryoprotectant-Free Vitrification of Abnormal Semen Sample: A Randomized Controlled Trial

Background:

The cryopreservation of semen samples by slow freezing remains as standard protocol. Recently, vitrification of spermatozoa was successfully reported with superior outcome. Till date, there is no randomized trial comparing the two different protocols.

Aim:

The aim of the present study is to evaluate the slow freezing with vitrification of the subfertile men spermatozoa to evaluate the progressive motility, vitality, and chromatin integrity.

Setting:

The study was conducted at University teaching hospital.

Design:

Study design involves randomized control trial.

Materials and Methods:

Twenty subfertile men with semen characteristics of severe oligoasthenozoospermia (SOA) and very SOA (VSOA) randomized to undergo slow freezing and vitrification protocol and cryopreserved at 1-month and 6-month storage interval, postthawed or warmed, samples were assessed for progressive motility, vitality, and hyaluronan binding. SPSS version 14 software was used for statistical analysis.

Results:

The SOA samples at 1 month revealed significantly higher motility (42% [22%–74%] vs. 7% [1%–13%]; P = 0.015) and vitality (57% [45%–78%] vs. 34.5% [27–42]; P < 0.001) following vitrification compared to slow-freeze method. For Very severe oligoasthenozoospermia (VSOA), the motility was significantly higher following vitrification (14.5% [2%–32%] vs. 2.5% [0%–4%]; P = 0.007). At 6 months, no statistically significant difference in motility was found between the two groups for Severe Oligoasthenozoospermia (SOA) samples (27% [13%–62%] vs. 8% [0%–11%]; P = 0.066), but motility was significantly higher following vitrification for VSOA samples (12.5% [3%–32%] vs. 2% [1%–5%]; P = 0.019). The hyaluronan-binding assay was comparable in both the groups at 6 months.

Conclusions:

The current study found the vitrification method involving the use of only nonpermeable cryoprotectants for cryopreservation of abnormal semen sample to be an effective alternative to the conventional slow-freeze technique.

Advanced Maternal Age in IVF: Still a Challenge? The Present and the Future of Its Treatment

Advanced maternal age (AMA; >35 year) is associated with a decline in both ovarian reserve and oocyte competence. At present, no remedies are available to counteract the aging-related fertility decay, however different therapeutic approaches can be offered to women older than 35 year undergoing IVF. This review summarizes the main current strategies proposed for the treatment of AMA: (i) oocyte cryopreservation to conduct fertility preservation for medical reasons or "social freezing" for non-medical reasons, (ii) personalized controlled ovarian stimulation to maximize the exploitation of the ovarian reserve in each patient, (iii) enhancement of embryo selection via blastocyst-stage preimplantation genetic testing for aneuploidies and frozen single embryo transfer, or (iv) oocyte donation in case of minimal/null residual chance of pregnancy. Future strategies and tools are in the pipeline that might minimize the risks of AMA through non-invasive approaches for embryo selection (e.g., molecular analyses of leftover products of IVF, such as spent culture media). These are yet challenging but potentially ground-breaking perspectives promising a lower clinical workload with a higher cost-effectiveness. We also reviewed emerging experimental therapeutic approaches to attempt at restoring maternal reproductive potential, e.g., spindle-chromosomal complex, pronuclear or mitochondrial transfer, and chromosome therapy. In vitro generation of gametes is also an intriguing challenge for the future. Lastly, since infertility is a social issue, social campaigns, and education among future generations are desirable to promote the awareness of the impact of age and lifestyle habits upon fertility. This should be a duty of the clinical operators in this field.

Open versus closed vitrification system of human oocytes and embryos: a systematic review and meta-analysis of embryologic and clinical outcomes

BACKGROUND

The objective of this study was to carry out a systematic review and meta-analysis of embryologic and clinical outcomes following open versus closed vitrification of human oocytes and embryos.

METHODS

An electronic literature search was conducted in main electronic databases up to June 30, 2018 using the following key terms: 'oocyte', 'embryo', 'blastocyst', 'vitrification', 'cryopreservation', 'device', 'survival rate', 'pregnancy rate', etc. A meta-analysis was performed using a random effect model to estimate the value of risk ratios (RRs) and 95% confidence interval (CI). Subgroup analyses and sensitivity analyses were carried out to further confirm the results.

RESULTS

Twelve (Eight prospective and four retrospective) studies comparing open versus closed vitrification of human oocytes or embryos were included. For prospective studies on oocytes, no evidence for a significant difference in cryosurvival rate (RR = 0.91, 95% CI: 0.80-1.03, P = 0.14; n = 2048) or clinical pregnancy rate (RR = 1.29, 95% CI: 0.80-2.06, P = 0.30; n = 150) was observed. Additionally, there were no significant differences between the two methods concerning secondary endpoints included positive βHCG rate, implantation rate, miscarriage rate, ongoing pregnancy rate, live birth rate, cancellation rate, babies born per transferred blastocysts, or multiple birth rate (P > 0.05). The results of the retrospective studies were similar as the prospective studies.

CONCLUSIONS

It is still impossible to conclude that closed vitrification system could be a substitution for open system in human oocyte and embryo cryopreservation based on current evidence. Therefore, more well-designed prospective studies addressing these issues are still warranted.

Hydrogel Cryopreservation System: An Effective Method for Cell Storage

At present, living cells are widely used in cell transplantation and tissue engineering. Many efforts have been made aiming towards the use of a large number of living cells with high activity and integrated functionality. Currently, cryopreservation has become well-established and is effective for the long-term storage of cells. However, it is still a major challenge to inhibit cell damage, such as from solution injury, ice injury, recrystallization and osmotic injury during the thawing process, and the cytotoxicity of cryoprotectants. Hence, this review focused on different novel gel cryopreservation systems. Natural polymer hydrogel cryopreservation, the synthetic polymer hydrogel cryopreservation system and the supramolecular hydrogel cryopreservation system were presented, respectively. Due to the unique three-dimensional network structure of the hydrogel, these hydrogel cryopreservation systems have the advantages of excellent biocompatibility for natural polymer hydrogel cryopreservation systems, designability for synthetic polymer hydrogel cryopreservation systems, and versatility for supramolecular hydrogel cryopreservation systems. To some extent, the different hydrogel cryopreservation methods can confine ice crystal growth and decrease the change rates of osmotic shock in cell encapsulation systems. It is notable that the cryopreservation of complex cells and tissues is demanded in future clinical research and therapy, and depends on the linkage of different methods.

COMFFETI, Combined Fresh and Frozen Embryo Transfers per Individual: A New Index of Quality Control for The Performance of emberyologic Labs in The Emerging Era of Segmentation of Cycle and Freeze-All Strategy

The efficacy of in vitro fertilization (IVF) for treating human infertility has only one final efficacy index and that is the achievement of a delivery. However, with the evolution of the freeze-all strategy, a new problem is arising for evaluating the performance of an embryological team. The aim of the study was to present a new representative index, combining fresh and frozen embryo transfer success rates. In this opinion article, apart from the effectiveness of managing fresh gametes and embryos, we wish to evaluate the efficacy of the processes of both freezing and thawing of the produced embryos. The reporting of pregnancy rates of an IVF unit in the past was primarily laying in the fresh embryo transfer (ET) pregnancy rates. Now with the most frequent utilization of freeze-all strategy, it does not seem logical to report only on poor prognosis patients as all the good cases are postponed for thawed cycles. Ongoing implementation of the freeze-all strategy has indicated the need to establish a new representative index that may combine the success of both fresh and frozen cycles performed in the same woman; an index that may not be biased by the policy of an IVF center towards or against the freeze-all strategy. This newly proposed index, which is referred to as COMFFETI (Combined Fresh & Frozen Embryo Transfers per Individual), describes the optimal way to report final reproductive outcomes in the present opinion article.

Reproductive outcomes of vitrified blastocyst transfer in modified natural cycle versus mild hormonally stimulated and artificial protocols: A randomized control trial

OBJECTIVE

This study set out to investigate the pregnancy outcome of natural cycle regimen versus other endometrial preparation protocols with vitrification thawed blastocyst transfer (VTBT) cycles.

METHODS

This control trial study was carried out on 123 women undergoing VTBT. The women were randomly divided into three groups of endometrial preparation before VTBT; 1. Modified natural ovulation cycle with using HCG (n=32) 2. Mild hormonally stimulated cycle by low dose Clomiphene Citrate (n=30) and 3. Artificial cycle induced with estradiol and progesterone supplementation (n=61). Following endometrial preparation, the thawed blastocyst was vitrified and transferred. Reproductive outcome and endometrium characteristic were evaluated in the three groups.

RESULTS

The three above-mentioned protocols resulted in clinical pregnancy rates of 21.43% vs. 13.79% vs. 15.25%, respectively; without statistical differences. The ongoing pregnancy rates did not show any significant differences among the three groups (21.43% vs. 13.79% vs. 13.56%), respectively. In addition, the miscarriage rates were compared in the three groups. The endometrial thickness on the day of progesterone or human chorionic gonadotropin administration were more frequently observed in the artificial and modified natural cycle versus hormonally stimulated groups (8.34±0.89 vs. 7.3±1.4, p<0.001; 8.13±0.95 vs. 7.3±1.4, p<0.001). There was no significant difference regarding triple-line endometrial patterns in the three groups.

CONCLUSION

The natural cycle with HCG trigger could be considered as an alternative protocol to mild hormonally or artificial cycle regimens in vitrification thawed blastocyst transfers.