A simple and economic protocol for efficient in vitro fertilization using cryopreserved mouse sperm.

The advent of genome editing tools like CRISPR/Cas has substantially increased the number of genetically engineered mouse models in recent years. In support of refinement and reduction, sperm cryopreservation is advantageous compared to embryo freezing for archiving and distribution of such mouse models. The in vitro fertilization using cryopreserved sperm from the most widely used C57BL/6 strain has become highly efficient in recent years due to several improvements of the procedure. However, purchase of the necessary media for routine application of the current protocol poses a constant burden on budgetary constraints. In-house media preparation, instead, is complex and requires quality control of each batch. Here, we describe a cost-effective and easily adaptable approach for in vitro fertilization using cryopreserved C57BL/6 sperm. This is mainly achieved by modification of an affordable commercial fertilization medium and a step-by-step description of all other necessary reagents. Large-scale comparison of fertilization rates from independent lines of genetically engineered C57BL/6 mice upon cryopreservation and in vitro fertilization with our approach demonstrated equal or significantly superior fertilization rates to current protocols. Our novel SEcuRe (Simple Economical set-up for Rederivation) method provides an affordable, easily adaptable and harmonized protocol for highly efficient rederivation using cryopreserved C57BL/6 sperm for a broad application of colony management in the sense of the 3Rs.

Oocyte cryopreservation versus ovarian tissue cryopreservation for adult female oncofertility patients: a cost-effectiveness study.

PURPOSE: In December 2019, the American Society for Reproductive Medicine designated ovarian tissue cryopreservation (OTC) as no longer experimental and an alternative to oocyte cryopreservation (OC) for women receiving gonadotoxic therapy. Anticipating increased use of OTC, we compare the cost-effectiveness of OC versus OTC for fertility preservation in oncofertility patients. METHODS: A cost-effectiveness model to compare OC versus OTC was built from a payer perspective. Costs and probabilities were derived from the literature. The primary outcome for effectiveness was the percentage of patients who achieved live birth. Strategies were compared using incremental cost-effectiveness ratios (ICER). All inputs were varied widely in sensitivity analyses. RESULTS: In the base case, the estimated cost for OC was $16,588 and for OTC $10,032, with 1.56% achieving live birth after OC, and 1.0% after OTC. OC was more costly but more effective than OTC, with an ICER of $1,163,954 per live birth. In sensitivity analyses, OC was less expensive than OTC if utilization was greater than 63%, cost of OC prior to chemotherapy was less than $8100, cost of laparoscopy was greater than $13,700, or standardized discounted costs were used. CONCLUSIONS: With current published prices and utilization, OC is more costly but more effective than OTC. OC becomes cost-saving with increased utilization, when cost of OC prior to chemotherapy is markedly low, cost of laparoscopy is high, or standardized discounted oncofertility pricing is assumed. We identify the critical thresholds of OC and OTC that should be met to deliver more cost-effective care for oncofertility patients.

Cost-effectiveness of freeze-all policy - A retrospective study based upon the outcome of cumulative live births.

OBJECT: We have previously reported that cumulative live birth rates (CLBRs) are higher in the freeze-all group compared with controls (64.3% vs. 45.8%, p = 0.001). Here, we aim to determine if the freeze-all policy is more cost-effective than fresh embryo transfer followed by frozen-thawed embryo transfer (FET). MATERIALS AND METHODS: The analysis consisted of 704 ART (Assisted reproductive technology) cycles, which included in IVF (In vitro fertilisation) and ICSI (Intra Cytoplasmic Sperm Injection) cycles performed in Taichung Veterans General Hospital, Taiwan between January 2012 and June 2014. The freeze-all group involved 84 patients and the fresh Group 625 patients. Patients were followed up until all embryos obtained from a single controlled ovarian hyper-stimulation cycle were used up, or a live birth had been achieved. The total cost related to treatment of each patient was recorded. The incremental cost-effectiveness ratio (ICER) was based on the incremental cost per couple and the incremental live birth rate of the freeze-all strategy compared with the fresh ET strategy. Probabilistic sensitivity analysis (PSA) and a cost-effectiveness acceptability curve (CEAC) were performed. RESULTS: The total treatment cost per patient was significantly higher for the freeze-all group than in the fresh group (USD 3419.93 ± 638.13 vs. $2920.59 ± 711.08 p < 0.001). However, the total treatment cost per live birth in the freeze-all group was US $5319.89, vs. US $6382.42 in the fresh group. CEAC show that the freeze-all policy was a cost-effective treatment at a threshold of US $2703.57 for one additional live birth. Considering the Willingness-to-pay threshold per live birth, the probability was 60.1% at the threshold of US $2896.5, with the freeze-all group being more cost-effective than the fresh-ET group; or 90.1% at the threshold of $4183.8. CONCLUSION: The freeze-all policy is a cost-effective treatment, as long as the additional cost of US $2703.57 per additional live birth is financially acceptable for the subjects.

Planned oocyte cryopreservation (Planned OC): systematic review and meta-analysis of cost-efficiency and patients' perspective.

BACKGROUND: Advances in vitrification techniques have enabled planned oocyte cryopreservation ('Planned OC'). OBJECTIVES: To explore the cost-efficiency and utilisation of planned OC, as well as patients' perspectives on the process. SEARCH STRATEGY: A systematic search in PubMed/MEDLINE, Embase, Cochrane Database and PsychINFO, for all relevant studies published between January 2007 and December 2019. SELECTION CRITERIA: The protocol followed PRISMA guidelines in PECO format, and was registered with PROSPERO. DATA COLLECTION AND ANALYSIS: Two independent reviewers evaluated all manuscripts for inclusion eligibility. Authors were contacted for missing data. Included studies were assessed for risk of bias and for heterogeneity. Weighted effects were measured and plotted. MAIN RESULTS: The search yielded 12 545 records, of which 43 were included. Planned OC is cost-efficient at 35, assuming 60% utilisation; and at 37 assuming utilising donor sperm when necessary. At 38 it is cost-efficient to defer planned OC in favour of undergoing 2 IVF cycles. Currently, utilisation of banked-oocytes within 22-58 months, is up to 15%. Nine percent of warmed banked oocytes result in life births. Online resources and treating physicians are equally important sources of information regarding planned OC. Most patients think planned OC is ideal before age 35 and are not fully aware of what the process entails and tend to overestimate the success rates. The main barrier to wider endorsement of planned OC is being wary of potential health implications or of limited success. CONCLUSION: Planned OC is an adequate method for preserving fertility. However, knowledge gaps result in under-utilisation leading to reduced cost-efficiency. TWEETABLE ABSTRACT: Identifying facilitators and barriers for wider adoption of banking oocytes can enhance the cost-efficiency of this modality.

Development of a fast and user-friendly cryopreservation protocol for sweet potato genetic resources.

Sweet potato (Ipomoea batatas) is one of the ten most important staple crops and provides a livelihood for many people around the globe. To adapt to ever-changing circumstances farmers and breeders need to have access to a broad diversity of germplasm. This study focuses on the development of a cryopreservation protocol that allows the long term storage of different sweet potato cultivars. For this, a droplet vitrification protocol was optimized, comparing several parameters; preculture method (0.3 M sucrose vs no preculture); meristem position (axillary vs apical); plant age (3 to 9 weeks); regeneration medium (MS + 2.22 µM BA, Hirai and MS); and length of loading solution treatment (20 to 360 min). Two months after cryopreservation, the regeneration rates of the meristems were compared, which resulted in significant differences for the preculture method, meristem position and loading solution. With these new insights an optimized droplet vitrification protocol was developed with the following parameters: use of 3-9 week old axillary meristems, no preculture phase, 20 min LS treatment, 30 min PVS2 treatment, exposure to liquid nitrogen by droplet vitrification, warming treatment in RS for 15 min, 1 day 0.3 M sucrose recuperation culture, 1 month MS + 2.22 µM BA followed by 1 month of MS cultures. This protocol was subsequently tested on 10 representative accessions resulting in a post cryopreservation regeneration rate of more than 40% for 70% of the tested cultivars, showing that this protocol could be implemented for a large portion of existing sweet potato collections.

E-Freeze - a randomised controlled trial evaluating the clinical and cost effectiveness of a policy of freezing embryos followed by thawed frozen embryo transfer compared with a policy of fresh embryo transfer, in women undergoing in vitro fertilisation: a statistical analysis plan.

BACKGROUND: The E-Freeze trial is a multi-centre randomised controlled trial of fresh versus frozen embryo transfer for women undergoing in vitro fertilisation. This paper describes the statistical analysis plan for the E-Freeze trial. METHODS AND DESIGN: E-Freeze is a two-arm parallel-group, multi-centre, individually randomised controlled trial to determine if a policy of freezing embryos, followed by thawed frozen embryo transfer, results in a higher healthy baby rate when compared with the current policy of transferring fresh embryos. Couples undergoing their first, second or third cycle of in vitro fertilisation at fertility centres in the UK were randomised to either fresh or frozen embryo transfer. The primary outcome is a healthy baby, defined as a live singleton baby born at term with an appropriate weight for gestation. This paper describes the statistical analysis plan for the trial, including the analysis principles, definitions of outcomes, methods for primary analysis, pre-specified subgroup analysis and sensitivity analysis. This plan was finalised prior to completion of recruitment to the trial. TRIAL REGISTRATION: ISRCTN registry: ISRCTN61225414 . Registered on 29 December 2015.

Collection of Frozen Rodent Brain Regions for Downstream Analyses.

As our understanding of neurobiology has progressed, molecular analyses are often performed on small brain areas such as the medial prefrontal cortex (mPFC) or nucleus accumbens. The challenge in this work is to dissect the correct area while preserving the microenvironment to be examined. In this paper, we describe a simple, low-cost method using resources readily available in most labs. This method preserves nucleic acid and proteins by keeping the tissue frozen throughout the process. Brains are cut into 0.5-1.0 mm sections using a brain matrix and arranged on a frozen glass plate. Landmarks within each section are compared to a reference, such as the Allen Mouse Brain Atlas, and regions are dissected using a cold scalpel or biopsy punch. Tissue is then stored at -80 °C until use. Through this process rat and mouse mPFC, nucleus accumbens, dorsal and ventral hippocampus and other regions have been successfully analyzed using qRT-PCR and Western assays. This method is limited to brain regions that can be identified by clear landmarks.

Cost-Effectiveness of Antifungal Supplementation of Corneal Cold Storage Media.

PURPOSE: To evaluate the cost-effectiveness of supplementing hypothermic cold storage media (CSM) with antifungal therapy. DESIGN: Cost-effectiveness analysis (CEA). PARTICIPANT: Base case of a patient with Fuch's endothelial dystrophy undergoing a first eye keratoplasty. METHODS: Cost-effective analysis of the base case with corneal tissue stored in CSM or CSM supplemented with antifungal therapy over a 16-year time horizon. Multiple clinical scenarios were considered, including endothelial keratoplasty (EK) and penetrating keratoplasty (PK); amphotericin B, voriconazole, caspofungin, and combination therapy; and third-party payer and societal perspectives. The incidences were derived from PubMed literature searches and average wholesale prices of medications; all costs were discounted 3% per annum and adjusted for inflation to 2019 US dollars. MAIN OUTCOME MEASURES: Incremental cost-effectiveness ratios (ICERs). RESULTS: In the reference case, a corneal endothelial graft stored in amphotericin B-supplemented CSM was the most cost-effective approach from a third-party payer and societal perspective. Probability sensitivity analysis (PSA) of the societal model for the EK was robust, with 93.5% being below an arbitrary willingness-to-pay threshold (WTP) of $20 000 per fungal infection averted. Voriconazole, caspofungin, and combination antifungals were less cost-effective than amphotericin B. The main factors influencing the CEA were the incidences of postkeratoplasty fungal infections, potential increases in graft failures, and antifungal costs. For grafts intended for PKs, antifungal supplementation was less cost-effective than for EKs. CONCLUSIONS: Antifungal supplementation with amphotericin B for EK grafts was the most cost-effective approach of the studied antifungals; however, the CEA was sensitive to potential changes in graft failure rates, underlining the importance of long-term safety studies. For full-thickness corneal grafts, antifungal supplementation was less cost-effective.

Engineering a bioprosthetic ovary for fertility and hormone restoration.

There has been an increase in childhood cancer survivors over the past few decades, and with this, an increased awareness of the co-morbidities of the treatment or disease that affect the survivor's quality-of-life. The increased rate of infertility among this patient group and the desire to have biological children voiced by childhood cancer survivors underscores the urgent need for fertility preservation and development of techniques to restore fertility and gonadal hormone function for this population. The ovarian tissue contains a finite source of female gametes that can be transplanted to restore ovarian function and has resulted in over one hundred reported live births. However, the success of biological offspring per ovarian tissue transplant, the reduced lifespan of these transplants, and the potential for these tissues to contain cancer cells from patients with metastatic diseases supports the need for improved options. One innovation that could improve ovarian transplantation is the development of a bioprosthetic ovary comprised of a 3D printed scaffold with isolated ovarian follicles. A murine bioprosthetic ovary restored ovarian hormones in ovariectomized mice, which also gave birth to healthy offspring. Research is ongoing to create the next iteration of the scaffold that would support ovarian follicles from large animal models and humans with the hopes of translating this technology for patients.

Study protocol: E-freeze - freezing of embryos in assisted conception: a randomised controlled trial evaluating the clinical and cost effectiveness of a policy of freezing embryos followed by thawed frozen embryo transfer compared with a policy of fresh embryo transfer, in women undergoing in vitro fertilisation.

BACKGROUND: Infertility affects one in seven couples; many of these need in vitro fertilisation (IVF). IVF involves external hormones to stimulate a woman's ovaries to produce eggs which are harvested surgically. Embryos, created in the laboratory by mixing eggs with sperm, are grown in culture for a few days before being replaced within the uterus (fresh embryo transfer). Spare embryos are usually frozen with a view to transfer at a later point in time - especially if the initial fresh transfer does not result in a pregnancy. Despite improvements in technology, IVF success rates remain low with an overall live birth rate of 25-30% per treatment. Additionally, there are concerns about health outcomes for mothers and babies conceived through IVF, particularly after fresh embryo transfer, including maternal ovarian hyperstimulation syndrome (OHSS) and preterm delivery. It is believed that high levels of hormones during ovarian stimulation could create a relatively hostile environment for embryo implantation whilst increasing the risk of OHSS. It has been suggested that freezing all embryos with the intention of thawing and replacing them within the uterus at a later stage (thawed frozen embryo transfer) instead of fresh embryo transfer, may lead to improved pregnancy rates and fewer complications. We aim to compare the clinical and cost effectiveness of fresh and thawed frozen embryo transfer, with the primary aim of identifying any difference in the chance of having a healthy baby. METHODS: E-Freeze is a pragmatic, multicentre two-arm parallel group randomised controlled trial where women aged ≥18 and < 42 years, with at least three good quality embryos are randomly allocated to receive either a fresh or thawed frozen embryo transfer. The primary outcome is a healthy baby, defined as a term, singleton, live birth with appropriate weight for gestation. Cost effectiveness will be calculated from a healthcare and societal perspective. DISCUSSION: E-Freeze will determine the relative benefits of fresh and thawed frozen embryo transfer in terms of improving the chance of having a healthy baby. The results of this pragmatic study have the potential to be directly transferred to clinical practice. TRIAL REGISTRATION: ISRCTN registry: ISRCTN61225414 . Date assigned 29/12/2015.

Cost-effectiveness of preimplantation genetic testing for aneuploidies.

OBJECTIVE: To evaluate the economical benefit of preimplantation genetic testing of aneuploidies (PGT-A) when applied in an extended culture and stringent elective single ET framework. DESIGN: Theoretical cost-effectiveness study. SETTING: Not applicable. PATIENTS/ANIMAL(S): None. INTERVENTION(S): Comparison of the cost-effectiveness between two IVF treatment strategies: serial transfer of all available blastocysts without genetic testing (first fresh transfer and subsequent frozen-thawed transfer); and systematic use of genetic testing (trophectoderm biopsy, freeze-all, and frozen-thawed transfers of euploid blastocysts). The costs considered for this analysis are based on regional public health system provider. MAIN OUTCOME MEASURE(S): Costs per live birth. RESULT(S): Cost-effectiveness profile of PGT-A improves with female age and number of available blastocysts. Sensitivity analyses varying the costs of ET, the costs of genetic analyses, the magnitude of the detrimental impact of PGT-A on live birth rate, and the crude live birth rates change to some extent the thresholds for effectiveness but generally confirm the notion that PGT-A can be economically advantageous in some specific subgroups. CONCLUSION(S): PGT-A can be cost-effective in specific clinical settings and population groups. Economic considerations deserve attention in the debate regarding the clinical utility of PGT-A.

Elective egg freezing without medical indications.

The aim of this review is to provide current knowledge on fertility preservation for non-medical reasons in women willing to postpone childbearing. The topic is highly debatable, starting from disagreement about its terminology, the number of eggs necessary to predict chances of success, and the safety and socio/ethical point of view. Cost analysis and discrepancies among countries' recommendations and regulations are described to confirm the controversies and unsolved issues around this very interesting topic. Finally, an overview on the returning rate of women among "egg bankers" and reasons behind their decisions are illustrated.

Evaluation and optimization of a methodology for the long-term cryogenic storage of Tetradesmus obliquus at - 80 °C.

Cryopreservation is a common methodology for long-term microalgae storage. Current cryopreservation methods are based on using diverse cryoprotectants and two-step cooling protocols, followed by sample storage at the temperature of liquid nitrogen (- 196 °C). However, the use of this methodology requires a continuous liquid N2 supply as well as facilities with dedicated equipment, which is not affordable for every laboratory. In our work, we report on the successful development of a simple and cost-effective method for the long-term cryogenic storage of Tetradesmus obliquus at temperatures (- 80 °C) used in commonly available deep freezers that are more readily accessible to laboratories. Two procedures were evaluated that were originally devised for other microalgae; this was followed by the optimization of critical parameters such as the sample's microalgal concentration and the cryoprotectant reagent's incubation time. Cell viability was monitored using the survival rates obtained by direct agar plating and the growth recovery times in liquid cultures. Viability-related variables were recorded following different storage times of up to 3 years. The main operational factors involved in the process (cell concentration, incubation time, and storage time) were statistically analyzed with regard to their influence on the survival rate. The statistical analysis showed interdependence (a two-factor interaction) between the cellular concentration and the cryoprotectant's incubation time, on the one hand, and between the incubation time and the storage time on the other. Survival rates above 70% were obtained under optimized conditions after 3 months of storage, along with 20-35% viabilities after 3 years. These results open up the possibility of extending this method to other Scenedesmaceae, or even other microalgal species, and for its use in resource-limited laboratories.

Early outcomes of a municipally funded oocyte cryopreservation programme in Japan.

One factor explaining the declining birth rate in Japan is the social advancement of women. Women are delaying marriage and childbirth, with many then facing so-called 'social infertility'. Advanced infertility treatment options, such as in vitro fertilization, are available, but the costs are high. Further, the success rates for 'older' women are only around 10%. We report the preliminary results of an oocyte cryopreservation programme promoted and subsidized by our city government. Citywide seminars were conducted to generate awareness of issues surrounding fertility. Among the total 81 attendees were women considering oocyte retrieval and the current practice of oocyte retrieval and cryopreservation and its associated risks were explained. Fifty-seven attendees, women under 34 years of age, were considered potential candidates for the procedure. These women wished to delay pregnancy for specific reasons, such as occupational demands. Twenty-six of these women expressed a definite desire for oocyte cryopreservation, and 19 have thus far completed the oocyte retrieval and cryopreservation procedure. Frozen MII oocytes have ranged in number from 3 to 22 per patient (mean ± SD, 8.3 ± 5.2). Outcomes thus far indicate that women whose fertility is at risk can be assisted by this fertility preservation method and that it will help address the problem of the declining birth rate in Japan.

A Cost-Effectiveness Analysis of Organ Preservation Methods for Deceased Donor Kidneys at High Risk for Delayed Graft Function in Brazil.

The clinical benefit of machine perfusion (MP) was recently assessed in a 1-year Brazilian multicenter prospective randomized trial, that showed that the use of MP was associated with a reduced incidence of delayed graft function (DGF) compared to static cold storage (SCS) in kidney transplant recipients (45% vs 61%). The objective of the present analysis is to consider the cost-effectiveness of MP relative to SCS based on clinical data from this Brazilian cohort. A decision tree model was constructed to simulate a population of 1000 kidney transplant recipients based on data derived from this Brazilian multicenter clinical trial. The model accounts for different health state utilities to estimate the cost-effectiveness of deceased donor kidney transplantation in Brazil comparing 2 kidney preservation methods: MP and SCS. The model accounts for 3 possible graft outcomes at 1 year post-transplantation: success (an immediate functioning kidney), failure (primary nonfunction requiring a return to dialysis), or DGF 1 year post-transplant. MP provided 612 total quality-adjusted life years (QALYs) (0.61 QALYs per patient) as compared to SCS (553 total QALYs, 0.55 QALYs per patient). MP was cost effective relative to SCS (US$22,117/QALY, R$70,606/QALY). The use of MP also resulted in more functioning grafts than SCS (821 vs 787), leading to a cost per functioning graft of US$38,033 (R$121,417). In conclusion, this analysis indicates that, despite the initial added cost associated with MP, the use of MP results in more functioning grafts (821 vs 787) and higher patient quality of life relative to SCS in Brazil.

Defining thresholds for abnormal premature progesterone levels during ovarian stimulation for assisted reproduction technologies.

OBJECTIVE: To evaluate methodologies to establish abnormal progesterone (P) levels on the day of trigger for recommending freeze only cycles. DESIGN: Threshold analysis and cost analysis. SETTING: Private ART practice. PATIENT(S): Fresh autologous ART. INTERVENTIONS(S): None. MAIN OUTCOME MEASURE(S): Live birth. RESULT(S): Fourteen established statistical methodologies for generating clinical thresholds were evaluated. These methods were applied to 7,608 fresh ART transfer cycles to generate various P thresholds which ranged widely from 0.4 to 3.0 ng/mL. Lower thresholds ranged from 0.4 to 1 ng/mL and classified the majority of cycles as abnormal as well as required very large number needed to treat (NNT) to increase one live birth. Frozen embryo transfer was cost-effective when P was ≥1.5 ng/mL, with 12% of the population having an abnormal test result and an NNT of 13. Statistical and cost-effective thresholds clustered between 1.5 and 2.0 ng/mL. CONCLUSION(S): Statistically significant thresholds for P were demonstrated as low as 0.4 ng/mL but resulted in a very large NNT to increase one live birth. A clinical benefit to a freeze-only approach was demonstrated above P thresholds ranging from 1.5 to 2.0 ng/dL. At these thresholds, elevated P has a demonstrable and clinically significant negative effect and captures a smaller percentage of the patient population at higher risk for fresh transfer failure, thus making freeze-only a cost-effective option.

A cost-effectiveness analysis of freeze-only or fresh embryo transfer in IVF of non-PCOS women.

STUDY QUESTION: Is a freeze-only strategy more cost-effective from a patient perspective than fresh embryo transfer (ET) after one completed In Vitro Fertilization/ Intracytoplasmic Sperm Injection (IVF/ICSI) cycle in women without polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: There is a low probability of the freeze-only strategy being cost-effective over the fresh ET strategy for non-PCOS women undergoing IVF/ICSI. WHAT IS KNOWN ALREADY: Conventionally, IVF embryos are transferred in the same cycle in which oocytes are collected, while any remaining embryos are frozen and stored. We recently evaluated the effectiveness of a freeze-only strategy compared with a fresh ET strategy in a randomized controlled trial (RCT). There was no difference in live birth rate between the two strategies. STUDY DESIGN, SIZE, DURATION: A cost-effectiveness analysis (CEA) was performed alongside the RCT to compare a freeze-only strategy with a fresh ET strategy in non-PCOS women undergoing IVF/ICSI. The effectiveness measure for the CEA was the live birth rate. Data on the IVF procedure, pregnancy outcomes and complications were collected from chart review; additional information was obtained using patient questionnaires, by telephone. PARTICIPANTS/MATERIALS, SETTING, METHODS: For all patients, we measured the direct medical costs relating to treatment (cryopreservation, pregnancy follow-up, delivery), direct non-medical costs (travel, accommodation) and indirect costs (income lost). The direct cost data were calculated from resources obtained from patient records and prices were applied based on a micro-costing approach. Indirect costs were calculated based on responses to the questionnaire. Patients were followed until all embryos obtained from a single controlled ovarian hyperstimulation cycle were used or a live birth was achieved. The incremental cost-effectiveness ratio (ICER) was based on the incremental cost per couple and the incremental live birth rate of the freeze-only strategy compared with the fresh ET strategy. Probabilistic sensitivity analysis (PSA) and a cost-effectiveness acceptability curve (CEAC) were also performed. MAIN RESULTS AND THE ROLE OF CHANCE: Between June 2015 and April 2016, 782 couples were randomized to a freeze-only (n = 391) or a fresh ET strategy (n = 391). Baseline characteristics including mean age, Body Mass Index (BMI), anti-Mullerian hormone, total dose of Follicle Stimulating Hormone (FSH), number of oocytes obtained, good quality Day 3 embryos, fertility outcomes and treatment complications were comparable between the two groups. The live birth rate (48.6% vs. 47.3%, respectively; risk ratio, 1.03; 95% Confidence Interval [CI], 0.89, 1.19; P = 0.78) and the average cost per couple (3906 vs. 3512 EUR, respectively; absolute difference 393.6, 95% CI, -76.2, 863.5; P = 0.1) were similar in the freeze-only group versus fresh ET. Corresponding costs per live birth were 8037 EUR versus 7425 EUR in the freeze-only versus fresh ET group, respectively. The incremental cost for the freeze-only strategy compared with fresh ET was 30 997 EUR per 1% additional live birth rate. The direct non-medical costs and indirect costs of infertility treatment strategies represented ~45-52% of the total cost. PSA shows that the 95% CI of ICERs was -263 901 to 286 681 EUR. Out of 1000 simulations, 44% resulted in negative ICERs, including 13.0% of simulations in which the freeze-only strategy was dominant (more effective and less costly than fresh ET), and 31% of simulations in which the fresh embryo strategy was dominant. In the other 560 simulations with positive ICERs, the 95% CI of ICERs ranged from 2155 to 471 578 EUR. The CEAC shows that at a willingness to pay threshold of 300 000 EUR, the probability of the freeze-only strategy being cost-effective over the fresh ET strategy would be 58%. LIMITATIONS, REASONS FOR CAUTION: Data were collected from a single private IVF center study in Vietnam where there is no public or insurance funding of IVF. Unit costs obtained might not be representative of other settings. Data obtained from secondary sources (medical records, financial and activity reports) could lack authenticity, and recall bias may have influenced questionnaire responses on which direct costs were based. WIDER IMPLICATIONS OF THE FINDINGS: In non-PCOS women undergoing IVF/ICSI, the results suggested that the freeze-only strategy was not cost-effective compared with fresh ET from a patient perspective. These findings indicate that other factors could be more important in deciding whether to use a freeze-only versus fresh ET strategy in this patient group. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by My Duc Hospital; no external funding was received. Ben Willem J. Mol is supported by an NHMRC Practioner Fellowship (GNT 1082548) and reports consultancy for Merck, ObsEva and Guerbet. Robert J. Norman has shares in an IVF company and has received support from Merck and Ferring. All other authors have no conflicts of interest to declare. TRIAL REGISTRATION NUMBER: Not applicable.