Effects of granulocyte-macrophage colony-stimulating factor supplementation in culture medium on embryo quality and pregnancy outcome of women aged over 35 years

Effects of high-normal fasting blood glucose on ART outcomes of frozen-thawed single blastocyst transfer in women with normal BMI

PURPOSE

This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).

METHODS

944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes.

PRIMARY OUTCOME

live birth rate (LBR).

RESULTS

LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541-0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018-2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.

CONCLUSIONS

In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.

Impact of culture media pre-equilibration methods on embryo development

This study investigates the influence of four culture media pre-equilibration methods on embryo development and clinical pregnancy outcomes. The methods are as follows: Method A involved covering media with fresh mineral oil in humid-type incubators for 24 h. Method B replicated Method A in dry-type incubators. Method C utilized pre-equilibrated (humidified) mineral oil to cover the media, also in humid-type incubators for 24 h. Method D followed the same process as Method C but in dry-type incubators. Subsequently, media from all groups were transferred to dry-type incubators for 72 h. Osmolality was measured at 24, 48, 72, and 96 h. For G1 PLUS, no significant differences were observed among groups at 24, 48, and 72 h. However, at 96 h, Groups B and D exhibited significantly higher osmolality than Groups A and C (A vs B, p = 0.043; A vs D: p = 0.046; B vs C, p = 0.043; C vs D, p = 0.046). No significant variations were found between Groups A and C or B and D. Similar results were obtained for G2 PLUS. A retrospective analysis of embryo development and clinical outcomes using Methods A revealed significant improvements in good blastocysts and available embryos compared with Method B for all (p = 0.005 and 0.004) and IVF cycles (p = 0.025 and 0.017). Method A also enhanced blastocyst formation in ICSI cycles (p = 0.017). However, clinical pregnancy outcomes did not significantly differ between Methods A and B. Pre-equilibrating culture media overnight in humid-type incubators, even when covered with fresh mineral oil, significantly mitigates osmolality rise and improves embryo development potential during embryo culture in dry-type incubators.

Mammalian embryo culture media: now and into the future

For over 70years, since the culture of the first mammalian embryo in vitro , scientists have undertaken studies to devise and optimise media to support the manipulation and culture of gametes and embryos. This area of research became especially active in the late 1970s onwards following the successful birth of the first human in vitro fertilised embryo. This review summarises some of the key advances in mammalian embryo culture media over time based on a greater understanding of the biochemical milieu of the reproductive tract. It highlights how learnings from studies in mice and agricultural species have informed human culture media compositions, in particular the inclusion of albumin, growth factors, cytokines, and antioxidants into contemporary culture media formulations, and how these advances may then in turn help to inform and guide development of in vitro culture systems used in other arenas, in particular agriculture. Additionally, it will highlight how the introduction of new technologies, such as timelapse, can influence current trends in media composition and usage that may see a return to a single step medium.

Disruption of CSF2RA in the bovine preimplantation embryo reduces development and affects embryonic gene expression in utero

The hypothesis that CSF2 plays a role in the preimplantation development of the bovine embryo was tested by evaluating consequences of inactivation of CSF2RA (the functional receptor in the embryo) for development of embryos in utero. CRISPR/Cas9 was used to alter sequences on exon 5 and intron 5 of CSF2RA, Control embryos were injected with Cas9 mRNA only. Embryos > 16 cells at day 5 after insemination were transferred to synchronized recipient females in groups of 7 to 24. Embryos were flushed from the uterus two days later. The proportion of recovered embryos that developed to the blastocyst stage was lower for knockout embryos (39%) than for control embryos (63%). RNA sequencing of individual morulae and blastocysts indicated a total of 27 (morula) or 15 (blastocyst) differentially-expressed genes (false discovery rate <0.05). Gene set enrichment analysis indicated that the knockout affected genes playing roles in several functions including cell signaling and glycosylation. It was concluded that signaling through CSF2RA is not obligatory for development of the bovine preimplantation embryo to the blastocyst stage but that CSF2 signaling does enhance the likelihood that the embryo can become a blastocyst and result in specific changes in gene expression.

The therapeutic effect of granulocyte colony stimulating factor (G-CSF) on potential biochemical pregnancy in patients with unexplained repeated transplantation failure (RIF): a case series and literature review

BACKGROUND

Biochemical pregnancy is a type of embryo transfer failure, patients with unexplained repeated implantation failure (RIF) also have higher biochemical pregnancy rate. Our study intends to evaluate the effect of granulocyte colony-stimulating factor (G-CSF) in patients with unexplained RIF with low hCG levels in early pregnancy.

METHODS

Unexplained RIF patients with low hCG levels after embryo transfer were allocated. G-CSF were administrated from the ninth days after embryo transfer. Clinical pregnancy, miscarriage and live birth rates were evaluated.

RESULTS

The clinical pregnancy and live birth rates were 52.5% and 30%.

CONCLUSION

G-CSF is an effective treatment for potential biochemical pregnancy in unexplained RIF patients.

Granulocyte-macrophage colony-stimulating factor-containing medium treatment after thawing improves blastocyst-transfer outcomes in the frozen- thawed blastocyst-transfer cycle

PURPOSE

To determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium could improve embryo-transfer outcomes in frozen-thawed blastocyst transfer.

METHODS

Patients who underwent frozen-thawed blastocyst transfer (430 women, aged 30-39 years, 566 cycles) were analyzed. Frozen-thawed blastocysts were cultured in GM-CSF-containing medium or control medium for 3-5 h, followed by transfer to the uterus. The embryo-transfer outcomes in the two groups were measured and compared, and a propensity score matching (1:1) method was used to balance the differences in baseline characteristics. We analyzed 213 matched samples.

RESULTS

In patients who underwent frozen-thawed blastocyst transfer with GM-CSF, the percentage of human chorionic gonadotropin-positive cases, biochemical pregnancies, clinical pregnancies, ongoing pregnancies, and live birth rates was 60.6%, 7.98%, 52.6%, 42.9%, and 40.9%, respectively, as compared with 45.1%, 3.29%, 41.8%, 31.1%, and 30.5%, respectively, for the control groups. The rates of human chorionic gonadotropin positivity (odds ratio [OR]: 1.87, 95% confidence interval: [CI]: 1.27-2.75), biochemical pregnancy (2.55, 1.04-6.29), clinical pregnancy (1.54, 1.05-2.27), ongoing pregnancy (1.64, 1.13-2.41), and live birth (1.67, 1.14-2.45) were significantly higher in the GM-CSF group than the control group. The incidence of pregnancy loss (22.3% vs. 27.0%) did not significantly differ between the groups.

CONCLUSION

The use of a GM-CSF-containing medium for blastocyst-recovery culture improved the live birth rate as a result of increased implantation rate in the frozen-thawed blastocyst-transfer cycle. The use of GM-CSF-containing medium following blastocyst thawing could be an effective choice for improving the blastocyst-transfer outcomes.

GM-CSF perturbs cell identity in mouse pre-implantation embryos

Growth factors became attractive candidates for medium supplementation to further improve the quality of embryo culture and to mimic in vivo nutrition. Granulocyte macrophage colony-stimulating factor (GM-CSF) is a cytokine influencing the maternal-fetal interface and supporting placental development in mouse and human. It is expressed in epithelial cells of the endometrium under the regulation of estrogens. The factor is already in clinical use and a large clinical trial showed that, if supplemented to an embryo culture medium, it leads to increased survival of embryos, especially in women with previous miscarriages. Animal and cell culture studies on isolated trophectoderm cells support an effect mainly on cellular expansion. Aim of this study was to investigate, if the supplementation of GM-CSF either in a human ART medium or in a mouse optimized medium, leads to a change in cell number and cell lineages in the early pre-implantation mouse embryo. Our data shows that mouse GM-CSF increased total cell numbers with increasing concentrations. This increase of cell number has not been found in embryos cultured in ART media with or without human GM-CSF (hGM-CSF) or in a mouse medium supplemented with different concentrations of hGM-CSF. The changes were caused by a marked difference in TE and primitive endoderm cell numbers but not due to a change in epiblast cell numbers. Additionally, results show an ectopic expression of NANOG among trophectoderm cells in both, human ART media (with and without GM-CSF) and at increasing concentrations in the mouse and the human GM-CSF supplemented media. In conclusion, we could show that GM-CSF has an effect on cell identity in mice, which might probably also occur in the human. Therefore, we would like to rare awareness that the use of supplements without proper research could bare risks for the embryo itself and probably also in the post-implantation phase.

Programming of postnatal phenotype caused by exposure of cultured embryos from Brahman cattle to colony-stimulating factor 2 and serum

Alterations in the environment of the preimplantation embryo can affect competence to establish pregnancy and phenotype of resultant calves. In this study, the bovine embryo produced in vitro was used to evaluate postnatal programming actions of the embryokine colony-stimulating factor 2 (CSF2) and serum, which is a common additive of culture media. Oocytes were collected by ovum pick up from Brahman donors and fertilized with semen from Brahman bulls. Embryos were randomly assigned to one of the three treatments: vehicle, CSF2 10 ng/mL, or 1% (v/v) serum. Treatments were added to the culture medium from day 5 to 7 after fertilization. Blastocysts were harvested on day 7 and transferred into crossbred recipients. Postnatal body growth and Longissimus dorsi muscle characteristics of the resultant calves were measured. The percent of cleaved embryos becoming blastocysts was increased by serum and, to a lesser extent, CSF2. Treatment did not affect survival after embryo transfer but gestation length was shortest for pregnancies established with serum-treated embryos. Treatment did not significantly affect postnatal body weight or growth. At 3 mo of age, CSF2 calves had lower fat content in the Longissimus dorsi muscle and less subcutaneous fat over the muscle than vehicle calves. There was a tendency for cross-sectional area of the muscle to be smaller for serum calves than vehicle calves. Results confirm the importance of the preimplantation period as a window to modulate postnatal phenotype of resultant calves. In particular, CSF2 exerted actions during the preimplantation period to program characteristics of accumulation of intramuscular and subcutaneous fat of resultant calves. The use of a low serum concentration in culture medium from day 5 to 7 of development can increase the yield of transferrable embryos without causing serious negative consequences for the offspring.

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.

Therapeutic role of granulocyte macrophage colony-stimulating factor (GM-CSF) in patients with persistent thin endometrium: A prospective and randomized study

OBJECTIVE

To assess the effect of granulocyte macrophage colony-stimulating factor (GM-CSF) on unresponsive thin (<7 mm) endometrium in women undergoing frozen-thawed embryo transfer.

METHODS

A single-center, randomized, prospective study enrolled 304 women with thin unresponsive endometrium from Shanghai Ninth People's Hospital between March 2017 and May 2018. Of them, 161 patients received an intrauterine infusion of GM-CSF and 143 patients served as controls. After hysteroscopy, a gel with or without GM-CSF was administered to fill the uterine cavity completely or up to 5 mL only. The primary outcome was confirmed pregnancy and secondary outcomes included endometrial thickness and implantation rate.

RESULTS

Patients who were administered GM-CSF had a significantly higher chemical pregnancy rate (35.3% vs 20.0%; P=0.009) and clinical pregnancy rate (28.6% vs 13.3%; P=0.005) compared with patients in the control group. Patients treated with GM-CSF had significantly higher endometrial thickness compared with controls (7.83 ± 1.45 mm vs 7.37 ± 0.70 mm, P=0.003).

CONCLUSION

GM-CSF therapy can effectively increase endometrial thickness and improve the clinical pregnancy rate in patients with persistent thin endometrium. The therapeutic role of GM-CSF for infertile women under in vitro fertilization and embryo transfer (IVF-ET) treatment can be further explored.

CHINESE CLINICAL TRIAL REGISTER

ChiCTR-IPR-17011242.

Effects of resveratrol, granulocyte-macrophage colony-stimulating factor or dichloroacetic acid in the culture media on embryonic development and pregnancy rates in aged mice

The success rate of assisted reproductive technology is closely correlated with maternal age. Reproductive aging pathologies are frequently caused by impaired DNA repair, genomic instability, and mitochondrial dysfunction. Several reports have shown that resveratrol can prevent age-related diseases by improving mitochondrial function. Improved blastocyst development and mitochondrial output by dichloroacetic acid (DCA) supplementation were reported in aged mice. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has significant effects on implantation rates in women with previous miscarriages. Therefore, this study was conducted to observe how those compounds influence the developmental and the reproductive potential of aged oocytes. BDF1 female mice at 58-62 weeks old were used for this study. MII oocytes were fertilized and cultured in MRC media supplemented with or without resveratrol (0.5 μM), GM-CSF (2 ng/ml) or DCA (1.0 mM). The addition of resveratrol, GM-CSF or DCA tended to increase blastocyst development and pregnancy rates. Supplementation with resveratrol significantly increased the pregnancy and implantation rates (p < 0.05). Moreover, resveratrol decreased reactive oxygen species production and increased mitochondrial membrane potential. These results suggest that the addition of resveratrol can increase pregnancy outcomes in women of advanced maternal age.

The BlastGen study: a randomized controlled trial of blastocyst media supplemented with granulocyte-macrophage colony-stimulating factor

RESEARCH QUESTION

Does Embryogen®/BlastGen™ culture medium improve live birth rates compared with standard culture medium for women undergoing IVF and intracytoplasmic sperm injection (ICSI) with poor prognosis.

DESIGN

Randomized clinical trial. A total of 100 couples undergoing IVF/ICSI were randomly allocated to having their inseminated oocytes incubated in either Embryogen®/BlastGen™ sequential culture media or standard Cleavage/Blastocyst sequential culture media for 5 days (ClinicalTrials.gov Identifier: NCT02305420).

RESULTS

No statistically significant difference in live birth rate was found between the control group and the Embryogen®/BlastGen™ group (17 [34%] versus 11 [22%], respectively) (OR 0.55; 95% CI 0.22 to 1.32; P = 0.18). After adjustment for maternal age, body mass index and fertilization procedure, the blastulation rate reduced (40.6 ± 26.5 versus 24.6 ± 26.7; RR 0.70, CI 0.52 to 0.95; P < 0.05), and grade of the embryo transferred (OR 0.35, CI 0.16 to 0.77; P < 0.01) when Embryogen®/BlastGen™ medium was used.

CONCLUSION

A significant reduction in day-5 embryo outcome parameters was found using Embryogen®/BlastGen™ compared with standard medium, and insufficient evidence of a difference in pregnancy outcomes. Taking into consideration the small samples size, study limitations and strict inclusion criteria of this single-centre study, further research is needed to determine the efficacy of Embryogen®/BlastGen™ medium in couples undergoing IVF/ICSI.

The effects and mechanisms of GM-CSF on endometrial regeneration

BACKGROUND

Endometrial injury can result in thin endometrium and subfertility. Granulocyte macrophage colony stimulating factor (GM-CSF) contributes to tissue repair, but its role in endometrial regeneration has not been investigated.

METHODS

To determine the effect of GM-CSF on endometrial regeneration, we established a mouse model of thin endometrium by uterine perfusion with 20 μL 90% ethanol. Thin endometrium in mice was featured by lowered endometrial thickness, decreased expression of Ki67 in glandular cells, and a reduced number of implantation sites. To explore the mechanism of GM-CSF on endometrial regeneration, endometrium was obtained from patients undergoing hysterectomy or hysteroscopy and endometrial biopsy. Effects of GM-CSF on primary cultured human endometrial glandular and stromal cells were examined by the 5-bromo-2'-deoxyuridine (BrdU) proliferation assay and transwell migration assay, followed by exploration of the potential signaling pathway.

RESULTS

GM-CSF intraperitoneal (i.p.) injection significantly increased endometrial thickness, expression of Ki67 in endometrial glandular cells, and the number of implantation sites. GM-CSF significantly promoted proliferation of primary human endometrial glandular cells and migration of stromal cells. GM-CSF activated p-Akt and increased expressions of p70S6K and c-Jun, which were blocked by LY294002.

CONCLUSION

We found that GM-CSF could improve endometrial regeneration, possibly through activating PI3K/Akt signaling pathway.

Relationship between granulocyte-macrophage colony-stimulating factor, embryo quality, and pregnancy outcomes in women of different ages in fresh transfer cycles: a retrospective study

This study aimed to explore the effects of low-concentration (0.6 ng/mL) granulocyte-macrophage colony-stimulating factor (GM-CSF) supplementation on human embryo quality and pregnancy outcomes in patients with fresh transfer cycles. The data were retrospectively collected from 719 hyperstimulation cycles of 631 patients divided into two groups: GM-CSF supplementation (0.6 ng/mL, n = 399) and control (n = 320). The embryo quality and pregnancy outcomes were compared. GM-CSF addition significantly increased the available embryo rate (52.0 vs. 48.1%, p < .05). In patients >38 years, it significantly enhanced cleavage (99.4 vs. 97.8%, p < .05) and blastocyst formation (45.7 vs. 34.9%, p < .05) rates but not pregnancy outcomes, including clinical pregnancy (power = 0.160) and implantation (power = 0.204) rates. The lack of a statistically significant difference could be related to low study power. These results suggest that low-concentration GM-CSF addition contributes to embryo quality improvement, especially in patients >38 years.IMPACT STATEMENTWhat is already known on this subject? Granulocyte-macrophage colony-stimulating factor (GM-CSF) has a beneficial effect on the development of human embryos in assisted reproductive technology.What do the results of this study add? Adding 0.6 ng/mL GM-CSF significantly increased the available embryo rate. In patients over 38 years of age, it statistically significantly enhanced the cleavage rate (99.4 vs. 97.8%, p < .05) and blastocyst formation rate (45.7 vs. 34.9%, p < .05).What are the implications of these findings for clinical practice and/or further research? GM-CSF benefits embryos with poorer development potential and a randomised clinical trial with a larger sample size should be performed.

The role of immunotherapy in in vitro fertilization: a guideline

Adjuvant immunotherapy treatments in in vitro fertilization (IVF) aim to improve the outcome of assisted reproductive technology (ART) in both the general ART population as well as subgroups such as patients with recurrent miscarriage or implantation failure. The purpose of this guideline is to evaluate the role of immunomodulating therapy in ART. Unfortunately, many of the evaluated therapies lack robust evidence from well-designed adequately powered randomized controlled trials to support their use. Immunotherapies reviewed in the present document are either not associated with improved live-birth outcome in IVF or have been insufficiently studied to make definitive recommendations.

Common medium versus advanced IVF medium for cryopreserved oocytes in heterologous cycles

Granulocyte-macrophage colony-stimulation factor plays different crucial roles during embryo implantation and subsequent development. Here we aimed to evaluate the effects of embryo cell culture medium, with the inclusion of granulocyte-macrophage colony-stimulation factor (GM-CSF), on embryo development and pregnancy rate. To this end, we took advantage of our retrospective observational study to correlate the outcomes from two different culture media. We included in this study 25 unselected patient from our IVF Center that underwent heterologous IVF cycle with crypreserved oocytes. We analyze the fertilization rate, pregnancy rate, and embryo quality at different day of transfer obtained from two different media composition. Our results show that the rate of fertilization and the pregnancy rate were increased using medium added with this particular type of cytokines (GM-CSF).

Murine embryos exposed to human endometrial MSCs-derived extracellular vesicles exhibit higher VEGF/PDGF AA release, increased blastomere count and hatching rates

Endometrial Mesenchymal Stromal Cells (endMSCs) are multipotent cells with immunomodulatory and pro-regenerative activity which is mainly mediated by a paracrine effect. The exosomes released by MSCs have become a promising therapeutic tool for the treatment of immune-mediated diseases. More specifically, extracellular vesicles derived from endMSCs (EV-endMSCs) have demonstrated a cardioprotective effect through the release of anti-apoptotic and pro-angiogenic factors. Here we hypothesize that EV-endMSCs may be used as a co-adjuvant to improve in vitro fertilization outcomes and embryo quality. Firstly, endMSCs and EV-endMSCs were isolated and phenotypically characterized for in vitro assays. Then, in vitro studies were performed on murine embryos co-cultured with EV-endMSCs at different concentrations. Our results firstly demonstrated a significant increase on the total blastomere count of expanded murine blastocysts. Moreover, EV-endMSCs triggered the release of pro-angiogenic molecules from embryos demonstrating an EV-endMSCs concentration-dependent increase of VEGF and PDGF-AA. The release of VEGF and PDGF-AA by the embryos may indicate that the beneficial effect of EV-endMSCs could be mediating not only an increase in the blastocyst’s total cell number, but also may promote endometrial angiogenesis, vascularization, differentiation and tissue remodeling. In summary, these results could be relevant for assisted reproduction being the first report describing the beneficial effect of human EV-endMSCs on embryo development.

Effects of different open cryo-carriers on embryo survival and clinical outcome in frozen embryo transfer cycle patients

The purpose of this study was to compare the efficacy of different open cryo-carriers: the CryoloopTM, CryotopTM, and CryoleafTM, in embryo survival and clinical outcome in patients with frozen embryo transfer (FET) cycle. We analyzed the embryo survival rate and clinical outcome in 325 patients of 348 FET cycles vitrified with the CryoloopTM (160 cycles), CryotopTM (105 cycles), or CryoleafTM (83 cycles). No significant differences were observed in embryo survival rate (98.8% vs. 100% vs. 97.7%, p > 0.05), HCG positive rate (58.8% vs. 63.8% vs. 57.8%, p > 0.05), biochemical pregnancy rate (6.9% vs. 11.4% vs. 9.6%, p > 0.05), or implantation rate (33.2% vs. 37.4% vs. 34.1%, p > 0.05) in the three groups respectively. The early abortion rate of the CryoloopTM group was significantly higher than that of the CryotopTM and CryoleafTM group (27.1% vs. 3.6% and 7.5%, p < 0.05). At the same time, the average female age of the CryoloopTM group was significantly older by 1 year than that of the CryotopTM and CryoleafTM group (33.29 ± 4.71 years vs. 31.96 ± 4.27 years and 31.1 ± 4.28 years, p < 0.05). There was no significant difference in take home baby rate (38.1% vs. 46.7% vs. 43.4, p > 0.05) or birth weight among the groups (2893.5 ± 780.8 g vs. 2778.4 ± 710.0 g vs. 2724.5 ± 838.8 g, p > 0.05). No case of neonatal malformation was observed in the present study. Overall, CryotopTM and CryoleafTM were effective for embryo vitrification at both the cleavage and blastocyst stage according to the results of clinical outcome and infant characteristics. However, CryoloopTM led to a decreased positive HCG rate and increased early abortion rate, heightened at the cleavage stage.

ABBREVIATIONS

LN₂: liquid nitrogen; CPA: cryoprotectant; ART: assisted reproductive technology; IVF: in vitro fertilization; ICSI: intracytoplasmic sperm injection; BMI: body mass index; FSH: follicular stimulation hormone; COH: controlled ovarian hyperstimulation; FET: frozen embryo transfer; mm: millimeter; HCG: human chorionic gonadotropin; RCT: randomized clinical trial; NC: natural cycle; AC: artificial cycle; EM: equilibration medium; DMSO: dimethyl sulphoxide; EG: ethylene glycol; VM: vitrification medium; WM: warming medium.