Whither cryopreservation? The landscape gets colder.

The increase in utilization and changing legal landscape has made the field of embryo and gamete cryopreservation fraught with potential future challenges and liabilities. Clinics should be aware of the current state of the science, potential legal ramifications of what is currently routine practice, and long-term ethical implications of our work.

The ART of cryopreservation and its changing landscape.

The purpose of this review is to educate the reader on the role that cryopreservation has played and continues to play in the ever-evolving field of assisted reproductive technologies, specifically in clinical human fertility treatment. We discuss the science behind the cryopreservation methods and investigated some of the major considerations that any clinic or cryobank faces in terms of risks and liabilities, physical challenges that accompany the constantly growing collection of cryopreserved specimens, and what this means on the ethical and legal front. Finally, we take a glimpse in the future to explore what may be on the horizon for the preservation of gametes and reproductive tissues.

In re: the disposition of frozen embryos: 2022.

Debates regarding reproductive rights have waxed and waned since the early twentieth century. The current front-and-center debate draws this discussion into tighter focus. Challenges to reproductive rights, changes in definitions of personhood and a pending decision regarding Roe v Wade could change the management and options regarding the disposition of frozen embryos. This commentary outlines how changes in abortion law and reproductive rights could potentially impact the options available to both patients and clinics.

Perinatal outcomes of singleton live births after preimplantation genetic testing during single frozen-thawed blastocyst transfer cycles: a propensity score-matched study.

OBJECTIVE: To determine whether singleton pregnancy achieved after preimplantation genetic testing (PGT) is associated with a higher risk of adverse perinatal outcomes than in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) singleton pregnancy. DESIGN: A retrospective cohort study. SETTING: A university-affiliated fertility center. PATIENT(S): This cohort study included singleton live births resulting from PGT (n = 232) and IVF/ICSI singleton pregnancies (n = 2,829) with single frozen-thawed blastocyst transfer. Multiple baseline covariates were used for propensity score matching, yielding 214 PGT singleton pregnancies matched to 617 IVF/ICSI singleton pregnancies. INTERVENTION(S): Trophectoderm biopsy. MAIN OUTCOME MEASURE(S): The primary outcome was gestational hypertension, and various clinical perinatal secondary outcomes related to maternal and neonatal health were measured. RESULT(S): Compared with IVF/ICSI singleton pregnancy, PGT singleton pregnancy was associated with a significantly higher risk of gestational hypertension (adjusted odds ratio, 2.58; 95% confidence interval, 1.32, 5.05). In the matched sample, the risk of gestational hypertension remained higher with PGT singleton pregnancy (odds ratio, 2.33; 95% confidence interval, 1.04, 5.22) than with IVF/ICSI singleton pregnancy. No statistical differences were noted in any other measured outcomes between the groups. CONCLUSION(S): The perinatal outcomes of PGT and IVF/ICSI singleton pregnancies were similar except for the observed potentially higher risk of gestational hypertension with PGT singleton pregnancy. However, because the data on PGT singleton pregnancies are limited, this conclusion warrants further investigation.

The impact of different cycle regimens on birthweight of singletons in frozen-thawed embryo transfer cycles of ovulatory women.

OBJECTIVE: To investigate whether different endometrial preparation regimens affect neonatal outcomes after frozen-thawed embryo transfer (FET). DESIGN: Retrospective cohort study. SETTING: Tertiary care academic medical center. PATIENTS: A total of 3,639 patients with live-born singletons were categorized into three groups on the basis of the type of endometrial preparation regimens. Of these, 1,225, 2,136, and 278 live-born singletons were conceived through natural cycle FET, artificial cycle FET, and stimulated cycle FET, respectively. INTERVENTION(S): None. MAIN OUTCOME MEASURES: The main outcomes were the measures of birthweight including the absolute mean birthweight, Z-score, low birthweight, high birthweight (HBW), small for gestational age, and large for gestational age (LGA). RESULTS: After controlling for a variety of covariates, singletons from the artificial cycle FET group had a higher mean birthweight and Z-score than those from the natural cycle FET group and stimulated cycle FET group. The risk of LGA infants significantly increased in the artificial cycle group (14.0%) than that in the natural cycle group (10.3%) and stimulated cycle group (7.6%). The risk of hypertensive disorders of pregnancy in the artificial cycle group (4.4%) was significantly higher than that in the natural cycle group (2.5%). The stimulated cycle FET singletons had a higher risk of low birthweight than the natural cycle FET singletons. The other perinatal outcomes, including the incidence of preterm birth, small for gestational age, and gestational diabetes mellitus, were comparable between the groups before or after adjustment for confounders. CONCLUSIONS: Singletons from artificial cycle FET were associated with a higher risk of LGA infants, and natural cycle FET may be a better regimen for ovulatory women. Our results indicate a link between the absence of the corpus luteum and adverse perinatal outcomes, and further studies are needed to detect the underlying mechanism.

Predictive Value of Swab Cultures for Cryopreserved Flaps During Delayed Cranioplasties.

OBJECTIVE: To assess the predictive value of swab cultures of cryopreserved skull flaps during cranioplasties for surgical site infections (SSIs). METHODS: A retrospective review was conducted of consecutive patients who underwent delayed cranioplasties with cryopreserved autografts between 2009 and 2017. The results of cultures obtained from swabs and infected surgical sites were assessed. The accuracy, sensitivity, and specificity of swab cultures for SSIs were evaluated. RESULTS: The study included 422 patients categorized into two groups, swab and nonswab, depending on whether swab cultures were implemented during cranioplasties. The overall infection rate was 7.58%. No difference was seen in infection rates between groups. There were 18 false-positive and no true-positive swab culture results. All bacteria between swab cultures and SSI cultures were discordant. Meanwhile, there were 19 false-negative swab cultures. The results showed high specificity but low sensitivity for swab cultures to predict SSI occurrence and the pathogens. CONCLUSIONS: Owing to low accuracy and sensitivity, swab cultures of cryopreserved autografts should not be routinely performed during delayed cranioplasties.

The association between season, day length, and temperature on clinical outcomes after cryopreserved embryo transfer.

OBJECTIVE: To investigate whether there is an association between season, temperature, and day length at oocyte retrieval and/or embryo transfer (ET) and clinical outcomes in frozen ET cycles. DESIGN: Retrospective cohort study. SETTING: Large academically affiliated research hospital. PATIENT(S): A total of 3,004 frozen ET cycles from 1,937 different women with oocyte retrieval and transfer between 2012 and 2017. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Implantation, clinical pregnancy, spontaneous abortion, and live birth. RESULT(S): Frozen ETs with oocyte retrieval dates in summer had 45% greater odds of clinical pregnancy (odds ratio [OR], 1.45; 95% confidence interval [CI], 1.15-1.82) and 42% greater odds of live birth (OR, 1.42; 95% CI, 1.13-1.79) compared with those with oocyte retrieval dates in winter. A 41% greater odds of clinical pregnancy (OR, 1.41; 95% CI, 1.16-1.71) and 34% greater odds of live birth (OR, 1.34; 95% CI, 1.10-1.62) were observed among transfers with an average temperature at oocyte retrieval in the highest tertile (17.2-33.3 °C) compared with those in the lowest tertile (-17.2-6.7 °C). There were no consistent associations between clinical outcomes and day length at oocyte retrieval or between season, day length, or temperature at transfer of thawed embryos. CONCLUSION(S): Warmer temperatures at oocyte retrieval are associated with higher odds of clinical pregnancy and live birth among frozen ET cycles. The consistent associations seen with oocyte retrieval dates and the lack of associations observed with ET dates suggest that any seasonality effects on in vitro fertilization success are related to ovarian function and not uterine receptivity.

Do frozen embryo transfers modify the epigenetic control of imprinted genes and transposable elements in newborns compared with fresh embryo transfers and natural conceptions?

OBJECTIVE: To determine whether the epigenetic control of imprinted genes (IGs) and transposable elements (TEs) differs at birth between fresh or frozen embryo transfers and natural conceptions. DESIGN: Prospective study. SETTING: University hospital. PATIENT(S): A total of 202 singleton births were divided into three groups: 84 natural pregnancies (controls), 66 in vitro fertilization/intracytoplasmic sperm injection with fresh embryo transfers, and 52 vitro fertilization/intracytoplasmic sperm injection with frozen embryo transfers. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Pyrosequencing was used to assess the DNA methylation profiles of three IGs (H19/IGF2:IG-DMR [two sequences], KCNQ1OT1:TSS-DMR, and SNURF:TSS-DMR) and two TEs (LINE-1 and HERV-FRD) in cord blood and placenta. The quantitative reverse transcriptase polymerase chain reaction was used to study the transcription of three IGs (H19, KCNQ1, and SNRPN) and two TEs (LINE-1 and ORF2). RESULT(S): After adjustment, the placental DNA methylation levels of H19/IGF2 were lower in the fresh embryo transfer group than in the control (H19/IGF2-seq1) and frozen embryo transfer (H19/IGF2-seq2) groups. The DNA methylation rate for LINE-1 was lower in placentas from the fresh embryo transfer group than in placentas from the control and frozen embryo transfer groups and for HERV-FRD compared with controls. In cord blood, DNA methylation levels were not significantly associated with the mode of conception. The relative expression of LINE-1 and ORF2 was decreased in both cord blood and placental tissues from fresh embryo transfer conceptions compared with natural conceptions and frozen embryo transfer conceptions. CONCLUSION(S): Compared with natural conceptions and frozen embryo transfers, fresh embryo transfers were associated with methylation and/or transcription changes in some TEs and IGs, mostly in placental samples, which could indicate altered placental epigenetic regulation resulting from ovarian stimulation protocols.

Endometrial thickness changes after progesterone administration do not affect the pregnancy outcomes of frozen-thawed euploid blastocyst transfer: a retrospective cohort study.

OBJECTIVE: To evaluate whether the change in endometrial thickness from progesterone administration day to transfer day is related to pregnancy outcomes in single frozen-thawed euploid blastocyst transfer cycles. DESIGN: Observational cohort study. SETTING: Single reproductive medical center. PATIENT(S): All patients were transferred with a single biopsied euploid blastocyst, and their endometrium was prepared with hormone replacement therapy (HRT). INTERVENTION(S): The endometrial thickness on the day of blastocyst transfer and progesterone administration was measured by transvaginal ultrasound, and the difference between them and the change ratio were calculated. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates and live birth rates. RESULT(S): Endometrial ultrasound images of 508 euploid blastocyst transfer cycles using HRT were evaluated by transvaginal ultrasound. Overall, pregnancy outcomes were comparable in different groups of endometrial thickness changes. The results of multiple logistic regression showed that the clinical pregnancy rate and live birth rate did not significantly increase with the increase in endometrial thickness change ratios (per 10%) in the fully adjusted model as a continuous variable. In the adjustment model as a categorical variable, there was no statistical difference in pregnancy outcomes among the groups with changes in endometrial thickness. Interaction analysis showed that after adjusting for confounders, there was no statistically significant interaction between the endometrial thickness change ratio and pregnancy outcomes in all subgroups. CONCLUSION(S): In the euploid blastocyst transfer cycle of preparing the endometrium with HRT, the endometrial thickness change ratio after progesterone administration was not related to pregnancy outcomes.

Serum luteal phase progesterone in women undergoing frozen embryo transfer in assisted conception: a systematic review and meta-analysis.

OBJECTIVE: To investigate the association between luteal serum progesterone levels and frozen embryo transfer (FET) outcomes. DESIGN: Systematic review and meta-analysis. SETTING: Not applicable. PATIENT(S): Women undergoing FET. INTERVENTION(S): We conducted electronic searches of MEDLINE, PubMed, CINAHL, EMBASE, the Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov, and grey literature (not widely available) from inception to March 2021 to identify cohort studies in which the serum luteal progesterone level was measured around the time of FET. MAIN OUTCOME MEASURE(S): Ongoing pregnancy or live birth rate, clinical pregnancy rate, and miscarriage rate. RESULT(S): Among the studies analyzing serum progesterone level thresholds <10 ng/mL, a higher serum progesterone level was associated with increased rates of ongoing pregnancy or live birth (relative risk [RR] 1.47, 95% confidence interval [CI] 1.28 to 1.70), higher chance of clinical pregnancy (RR 1.31, 95% CI 1.16 to 1.49), and lower risk of miscarriage (RR 0.62, 95% CI 0.50 to 0.77) in cycles using exclusively vaginal progesterone and blastocyst embryos. There was uncertainty about whether progesterone thresholds ≥10 ng/mL were associated with FET outcomes in sensitivity analyses including all studies, owing to high interstudy heterogeneity and wide CIs. CONCLUSION(S): Our findings indicate that there may be a minimum clinically important luteal serum concentration of progesterone required to ensure an optimal endocrine milieu during embryo implantation and early pregnancy after FET treatment. Future clinical trials are required to assess whether administering higher-dose luteal phase support improves outcomes in women with a low serum progesterone level at the time of FET. PROSPERO NUMBER: CRD42019157071.

Use of cryopreserved ovarian tissue in the Danish fertility preservation cohort.

OBJECTIVE: To evaluate the use of cryopreserved ovarian tissue in the Danish fertility preservation cohort. DESIGN: Retrospective cohort study. SETTING: University hospitals and fertility clinics. PATIENT(S): Ovarian tissue cryopreservation (OTC) was performed for 1,186 Danish girls and women from 1999-2020, of whom 117 subsequently underwent ovarian tissue transplantation (OTT). Subgroup 1 included 759 patients with a follow-up period of >5 years. Out of these, OTT rates were further analyzed for those patients who were alive and aged >24 years in July 2020 (subgroup 2; n = 554). INTERVENTION(S): OTC and OTT. MAIN OUTCOME MEASURE(S): OTT, death, donation of tissue. RESULT(S): In subgroup 1, 14% of the patients had undergone OTT, 18% had died, 9% had donated their tissue for research, and 59% still had their tissue stored. In subgroup 2, 19% had undergone OTT and for most diagnoses the OTT rates ranged from 15% to 22% with benign hematologic diseases having the highest OTT rate (35%). On the basis of the entire cohort, stratified age analysis indicated that women aged ≥30 years at OTC were more likely to return for OTT than women aged 18-29 years at OTC; mean storage times were 3.7 and 3.6 years, respectively. Only 4% of the girls aged <18 years at OTC had undergone OTT. CONCLUSION(S): The OTT rates depended on the diagnosis, age at OTC, and follow-up time. Specific criteria are needed for reporting and comparing OTT rates. Six out of 10 patients still had their cryopreserved tissue stored and longer follow-up is needed, especially for younger girls.

Oocyte vitrification for fertility preservation for both medical and nonmedical reasons.

Growing evidence of successful outcomes achieved with the oocyte vitrification technique has greatly contributed to its application in the field of fertility preservation (FP). The population that can benefit from FP includes women at a risk of losing their ovarian function because of either iatrogenic causes or natural depletion of their ovarian reserve. Therefore, oncological patients and healthy women who wish to delay motherhood for various reasons-elective FP-are currently being offered this option. Satisfactory oocyte survival rates and clinical outcomes, including cumulative live birth rates, have been reported in recent years. These studies show that age at oocyte retrieval strongly affects reproductive prognosis after FP. Therefore, elective FP patients should be encouraged to decide before they reach the age of 35 years to significantly increase their chances of success. The effect of age has also been observed in patients with cancer and women diagnosed with endometriosis. The reproductive outcome after FP is worse in patients with cancer, but a direct association between the disease and reproductive outcome is yet to be proven. Young patients (≤35 years) with endometriosis who have undergone cystectomy before oocyte retrieval for FP have worse outcomes than nonoperated women in age-matched groups. In addition, the number of oocytes used per patient is closely related to success in all populations, with considerable improvement in the result with the addition of a few oocytes, especially in healthy young patients.

Transplantation of cryopreserved ovarian tissue in a series of 285 women: a review of five leading European centers.

The feasibility of freezing and thawing ovarian tissue is nowadays widely documented. However, ovarian tissue transplantation (OTT) is happening at a much slower pace, and clinical experience is somewhat limited. In this review, five European centers present their collective experience of transplanting ovarian tissue in 285 women. The focus is on surgical techniques and OTT outcomes, reproductive outcomes, the impact of chemotherapy before ovarian tissue cryopreservation (OTC), the risk of relapse, and endocrine resumption and longevity of transplanted tissue. The risk of relapse due to reimplantation of ovarian tissue appears to be very low according to current data. Recovery of endocrine function is seen in almost all women undergoing transplantation of ovarian tissue, and about one in four gives birth to a healthy child. The efficacy of in vitro fertilization in these patients is not very high, however, and needs to be substantially improved. Radiation to the pelvis, especially with relatively high doses, appears to considerably decrease the likelihood of a successful pregnancy and may be contraindicated. Our results demonstrate that chemotherapy before OTC does not impair the chances of success, depending, of course, on the total dose and type of chemotherapy administered. At this early stage of development of OTT for restoration of fertility, the results are encouraging and demonstrate clear potential. However, the method is far from being fully developed and requires continued research efforts to optimize our approach.

Fertility preservation in men: a contemporary overview and a look toward emerging technologies.

Cancer and oncologic therapies can have significant adverse effects on male reproductive potential, leaving many men permanently infertile. Fertility preservation has emerged as a key survivorship issue over the past 20 years, and numerous professional societies have published guidelines calling for fertility preservation to become a routine component of oncologic care. Most males with cancer are able to produce a semen specimen for fertility preservation, but numerous other methods of sperm procurement are available for patients who cannot provide a sufficient sample. Despite these options, fertility preservation will remain a challenge for prepubertal boys and men without sperm production. For these patients, experimental and investigational approaches offer the hope that one day they will translate to the clinical arena, offering additional pathways for successful fertility preservation care.

Protective Effects of Curcumin on the Outcome of Cryopreservation in Human Sperm.

Cryopreservation causes decreased sperm fertility potential due to reactive oxygen species (ROS) production and physical-chemical damage, resulting in reduced sperm viability and motility. The addition of antioxidants to freezing media could protect sperm from cryo-damage, counteracting the harmful effects of ROS. The aim of this study was to assess the effects of curcumin supplementation in freezing medium on preventing cryo-damage in human semen. Semen samples collected from fertile men were cryopreserved in freezing medium supplemented with different concentrations of curcumin (2.5, 5, 10, and 20 µM). After freezing-thawing, sperm parameters, DNA fragmentation, intracellular ROS, and glutathione peroxidase 4 (GPX4) gene expression were evaluated. Supplementation with 20 µM curcumin in freezing medium caused increases in progressive and nonprogressive motility and significant reductions in intracellular ROS and DNA fragmentation in frozen-thawed sperm cells. Following cryopreservation, GPX4 mRNA expression was significantly upregulated in thawed semen supplemented with 20 µM curcumin compared to the control. The results showed that curcumin supplementation in freezing medium was protective against human sperm parameters and sperm DNA, counteracting oxidative damage induced by the freeze-thaw process.

Development of an emergency plan for in vitro fertilization programs: a committee opinion.

All in vitro fertilization programs and clinics should have a plan to protect fresh and cryopreserved human specimens (embryos, oocytes, sperm) and to provide contingencies for continuation or cessation of patient care in the event of an emergency or natural disaster. This document replaces the document titled "Recommendations for development of an emergency plan for in vitro fertilization programs: a committee opinion," last published in 2016 (Fertil Steril 2016;105:e11-3).

Fertility preservation in men and women: Where are we in 2021? Are we rising to the challenge?

Demand for fertility preservation in women for oncologic, nononcologic, and personal reasons has increased dramatically. Meeting that demand is a major challenge, and we are rising to the challenge. Mature oocyte cryopreservation after ovarian stimulation and ovarian tissue cryopreservation are both methods endorsed by the American Society for Reproductive Medicine (formerly The American Fertility Society), and numerous papers confirmed their efficacy. In girls and women with leukemia or cancers who are at a high risk of ovarian metastasis and who may not be eligible for ovarian tissue transplantation, restoration of fertility can only be achieved by in vitro methods. Male fertility preservation has also become a pressing issue and is extensively reviewed in the present journal issue.

Impacts of Cyclosporin A on clinical pregnancy outcomes of patients with a history of unexplained transfer failure: a retrospective cohort study.

BACKGROUND: A rapid development in assisted reproductive technology (ART) has led to a surge in its popularity among target couples. However, elucidation on the molecular mechanism and effective solutions for a common problem posed by ART, namely transfer failure, is still lacking. The new therapeutic potential of cyclosporin A (CsA), a typical immunosuppressant widely used in the treatment of rejection after organ transplantation, in recurrent pregnancy loss (RPL) patients may inspire some novel transfer failure therapies in the future. To further explore the clinical effects of CsA, this study investigated whether its application can improve clinical pregnancy outcomes in patients with a history of unexplained transfer failure in frozen-thawed embryo transfer (FET) cycles. METHODS: Data from a retrospective cohort investigation (178 frozen-thawed embryo transfer cycles in 178 patients) were analysed using binary logistic regression to explore the relationship between CsA treatment and clinical pregnancy outcomes; the odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated as a measure of relevancy. Implantation rate was the main outcome measure. RESULTS: There was no difference in the fine adjusted OR (95 % CI) of the implantation rate [1.251 (0.739-2.120)], clinical pregnancy rate [1.634 (0.772-3.458)], chemical pregnancy rate [1.402 (0.285-6.909)], take-home baby rate [0.872 (0.423-1.798)], multiple births rate [0.840 (0.197-3.590)], preterm birth [1.668 (0.377-7.373)], abnormal birth weight [1.834 (0.533-6.307)] or sex ratio [0.956 (0.339-2.698)] between the CsA-treated group and control group. No birth defects were observed in the present study. CONCLUSIONS: Although CsA does not affect infant characteristics, it has no beneficial effects on the clinical pregnancy outcomes in patients with a history of unexplained transfer failure in FET cycles.

Psychosocial determinants of women's intentions and willingness to freeze their eggs.

OBJECTIVE: To examine the psychosocial factors that influence Australian women's intentions to freeze their eggs. DESIGN: Initially, a qualitative elicitation study followed by a larger-scale quantitative study. SETTING: Both studies were conducted online. PATIENTS: A total of 234 Australian women 25-43 years of age, who identifed as heterosexual, had no children, were open to the idea of having children, were currently not pregnant, and did not have a diagnosis of medical infertility. INTERVENTION: None. MAIN OUTCOME MEASURE(S): Intentions and willingness of women to freeze their eggs. RESULT(S): Hierarchical multiple regression analyses showed that after accounting for demographic variables, there was strong support for the psychosocial predictors of attitude, pressure from others, and control perceptions as predictors of women's intentions to freeze their eggs. Of the additional variables, cognitive bias (influence of the media) was significant, and the final model accounted for 52.7% of variance in women's intentions to freeze their eggs. CONCLUSION(S): This study was the first to predict women's intentions to freeze their eggs using a well-established decision-making model, the theory of planned behavior. Messages designed to develop a positive attitude toward egg freezing, and to encourage an increased perception of personal control of the egg freezing process, as well as approval from others, could support women to investigate egg freezing, in consultation with appropriate medical advice, as an option when faced with possible future infertility. Effective strategies broaden fertility options for women faced with age-related fertility decline, maximize women's chances of a successful pregnancy, and, critically, prevent the often substantial psychological distress associated with involuntary childlessness.

Routine endometrial receptivity array in first embryo transfer cycles does not improve live birth rate.

OBJECTIVE: To compare the live birth rate between patients who undergo personalized embryo transfer (pET) after endometrial receptivity array (ERA) versus frozen embryo transfer (FET) with standard timing in first single euploid FET cycles. To report the rate of displacement of the window of implantation (WOI) in an infertile population without a history of implantation failure. DESIGN: Prospective cohort study of patients who underwent their first single euploid programmed FET. SETTING: Private fertility clinic. PATIENT(S): Patients who underwent first autologous single euploid programmed FET between January 2018 and April 2019. INTERVENTION(S): Endometrial biopsy with ERA followed by pET as indicated. MAIN OUTCOME MEASURE(S): Live birth rate and rate of receptive and nonreceptive ERA. RESULT(S): A total of 228 single euploid FET cycles were included in our analysis. Of those, 147 (64.5%) were ERA/pET cycles, and 81 (35.5%) were standard timing FET cycles. Endometrial receptivity array was receptive in 60/147 (40.8%) and nonreceptive in 87/147 (59.2%) patients. Nonreceptive ERAs were prereceptive in 93.1% of cases. The live birth rate did not differ between patients who underwent FET with standard timing and patients who underwent ERA/pET, 45/81 (56.6%) and 83/147 (56.5%), respectively. CONCLUSION(S): Our data do not support the routine use of ERA in an unselected patient population undergoing first autologous single euploid programmed embryo transfer.