Fertilization Embryo Research Articles

Evaluation of an automated dish preparation system for IVF and embryo culture using a mouse mode

Manual dish preparation for IVF in human fertility clinics or animal laboratories heavily relies on embryologists' experience, which can lead to occupational illness due to long-term and monotonous operation. Therefore, introducing an automated technique to replace traditional methods is crucial for improving working efficiency and reducing work burden for embryologists. In the current study in the mouse, both manual and automated methods were used to prepare IVF or embryo culture dishes. A one-way analysis of variance was conducted to compare several factors, including preparation time, qualified rates, media osmolality of dishes, fertilization rates, and embryonic development to assess the efficiency and potential of automated preparation. The results showed that automation system significantly reduced the required time and increased the efficiencies and qualified rates of dish preparation, especially for embryo culture dishes, without significantly altering medium osmolalities. There were no significant differences between two preparations in fertilization rates and embryo development in mice. Thus, automated dish preparation can improve working efficiency and qualified rates while maintaining fertilization rates and subsequent embryonic development without compromising osmolality stability of medium. It presents a superior alternative to manual preparation, reducing the workload of embryologists and facilitating the standardization of operational procedures.

Intracytoplasmic sperm injection does not improve the outcome of IVF treatments in patients with advanced maternal age or low oocyte number: A randomized controlled trial.

Intracytoplasmic sperm injection (ICSI) was introduced to achieve fertilization in cases of severe male factor infertility. However, ICSI is often used in cases of non-male factor infertility, such as advanced maternal age or low oocyte number, but the clinical benefit of the method in these indications has not been proven. A prospective randomized study was conducted in a university clinic between 2018 and 2020. Patients with ≥40 years of age and/or ≤4 oocytes with non-sever male factor infertility were randomized into conventional IVF or ICSI groups. Fertilization rate, embryo quality, implantation, clinical pregnancy and live birth rates were compared. A total of 336 IVF cycles (169 conventional IVF and 167 ICSI) were involved in the study. The fertilization rate was higher in the conventional IVF group compared to the ICSI group (IVF: 61.7%, ICSI: 53.4%, P=0.001). Embryo development and morphology did not show considerable difference between groups. Implantation, clinical pregnancy and live birth rate were 13.1%, 24.3% and 11.4% in the conventional IVF and 10.4%, 19.0%, 12.0% in the ICSI group. The differences were not significant. Subgroup analysis showed a significantly better clinical outcome following conventional IVF when advanced maternal age was accompanied by low oocyte number (Implantation: 11.7% vs 2.6%, P=0.027; Clinical pregnancy: 18.5% vs 4%, P=0.020). A significantly higher fertilization rate, a tendency for higher clinical pregnancy rate was found in conventional IVF treatments compared to ICSI. When advanced maternal age was associated with low oocyte number, ICSI resulted in a substantially lower chance of fertilization and clinical pregnancy. These data suggest that ICSI offers no advantage over conventional IVF in terms of fertilization, embryo quality, implantation and pregnancy rates for couples with advanced maternal age or with low oocyte number.

H19 Promoter DNA Methylation is Lower Among Early Abortion Patients Undergoing IVF Embryo Transfer.

H19 is the first long noncoding RNA (lncRNA) found to be associated with gene imprinting. It is highly expressed in the embryonic stage and may have important regulatory effects on human embryonic development. We investigated the differences between the levels of H19 promoter DNA methylation in the chorionic villi of patients who experienced spontaneous abortion (SA) following in vitro fertilization embryo transfer (IVF-ET) and those of patients with a normal early pregnancy (NEP). We also analyzed the associated DNA methyltransferase (DNMT) activity. Chorionic villus tissue from patients with SA and NEP were collected. The DNA methylation levels of two CpG islands in the promoter region of the H19 gene in the two groups were detected by bisulfite sequencing, and the mRNA expression of DNMTs was analyzed by real-time polymerase chain reaction. The sample size of each group was 32, and there were no significant differences in baseline data, including age, parity, and body mass index, between the two groups. Among the 7 CpG islands measured, the methylation rates of 3 CpG islands (CpG 1, 6, and 7) were significantly lower in the SA group than in the NEP group (P < 0.01). The methylation levels of the other 4 CpG islands were not significantly different between the two groups. There were no differences in the expression of DNMT1 between the two groups (P > 0.05), but DNMT3a and DNMT3b RNA levels were significantly lower in SA group than in the NEP group (P < 0.01). The lower H19 promoter DNA methylation levels found in the chorionic villi of patients with SA patients following IVF-ET may be explained by decreased expression of DNMT3a and DNMT3b.

Feasibility and efficiency of delayed ovarian stimulation and metaphase II oocyte banking for fertility preservation and childbearing desire after fertility-impairing treatment

The aim of our study was to evaluate the feasibility and efficiency of delayed ovarian stimulation and metaphase II oocyte banking for fertility preservation after fertility-impairing treatment regardless of the initial disease. We conducted a cohort study based on population of women < 40 years of age with diminished ovarian reserve caused by fertility-impairing treatment (n = 129). Three groups of women were compared according to the type of initial disease: hematological malignancies, solid tumors, and benign diseases. The primary endpoint was the number of metaphase II oocytes collected per woman. We studied the cumulative live-birth rate per cycle with fertilized metaphase II oocyte, for women who wanted to conceive. We studied 245 delayed controlled ovarian stimulation cycles in 129 women: 201 for fertility preservation and 44 for in vitro fertilization and fresh embryo transfers. The number of metaphase II oocytes collected per woman after banking was similar in the three groups, with a mean of 10.7 ± 4.6, 12.3 ± 9.1, and 10.1 ± 7.6 metaphase II oocytes (p = 0.46), respectively. In the subgroup of women who wanted to conceive, the cumulative live birth rate per woman was 38%, with 8 live births for these 21 women. After fertility-impairing treatment, practitioners should discuss a fertility preservation procedure for banking metaphase II oocytes.

The impact of female BMI on sperm DNA damage repair ability of oocytes and early embryonic development potential in intracytoplasmic sperm injection cycles.

Obesity adversely influences the quality of oocytes and embryos and can affect DNA repair in embryos, leading to reproductive issues. However, the effects of body mass index (BMI) on DNA repair ability in oocytes during intracytoplasmic sperm injection (ICSI) cycles have not yet been investigated. Therefore, this retrospective study aimed to analyze the influence of sperm DNA damage on embryo development and reproductive outcomes in overweight/obese and normal-weight women in ICSI cycles. A total of 1,141 patients who received the first fresh ICSI cycle treatments were recruited from July 2017 to July 2021. Based on the BMI of the women, all patients were divided into normal weight (18.5≤BMI<25 kg/m2; n=824; 72.22%) and overweight/obese (BMI≥25 kg/m2; n=317; 27.78%) groups. Furthermore, according to the sperm DNA fragmentation index (DFI), these two groups were subdivided into two subgroups: DFI<30% and DFI≥30%. In the normal-weight women group, the embryonic development and reproductive outcomes of ICSI cycles were not statistically different between the two subgroups (DFI<30% and DFI≥30%). However, in the overweight/obese women group, couples with a sperm DFI≥30% had a significantly lower fertilization rate (76% vs. 72.7%; p=0.027), cleavage rate (98.7% vs. 97.2%; p=0.006), and high-quality embryo rate (67.8% vs. 62.6%; p=0.006) than couples with a sperm DFI<30%. When injected sperm with high DFI into the oocytes of overweight/obese women, resulting in lower fertilization, cleavage, and high-quality embryo rates in ICSI cycles, and the decreased early developmental potential of embryos from overweight/obese patients may be caused by the diminished capacity of oocytes to repair sperm DNA damage.

The effects of male anxiety and depression on IVF outcomes.

What are the effects of male anxiety and depression on IVF outcomes? Men with anxiety had lower final total motile sperm counts (fTMSC) during IVF compared to men without anxiety; however, there were no differences in live birth rates (LBRs). Studies have shown that male anxiety causes low sperm motility, worse sperm morphology, and increased DNA fragmentation, which are known to be influential factors on fertilization rates and embryo quality during IVF. However, data are lacking on whether there is a direct association between male anxiety and/or depression and IVF outcomes. This was a survey-based, retrospective cohort study completed at a single, large hospital-affiliated fertility center with 222 respondents who underwent IVF with or without ICSI. The study was conducted between 6 September 2018 and 27 December 2022. Male partners of couples who underwent IVF or IVF/ICSI completed a Hospital Anxiety and Depression Scale (HADS) questionnaire. They were separated into two groups for both anxiety (HADS-A ≥ 8 or HADS-A < 8) and depression (HADS-D ≥ 8 or HADS-D < 8). Men with an elevated HADS-A or HADS-D score ≥8 were considered to have anxiety or depression, respectively. The primary outcome was LBR. Secondary outcomes included semen parameters at the time of IVF, cycle outcomes, pregnancy outcomes, and prevalence of erectile dysfunction and low libido. There were a total of 222 respondents, of whom 22.5% had a HADS-A ≥ 8 and 6.5% had a HADS-D ≥ 8. The average age of respondents was 37.38 ± 4.90 years old. Antidepressant use was higher in the respondents with a HADS-A or HADS-D ≥ 8 (P < 0.05). Smoking use was similar between groups for both HADS-A and HADS-D (P > 0.05). When adjusted for male BMI, antidepressant use and smoking, men with a HADS-A or HADS-D ≥ 8 had similar rates of erectile dysfunction (adjusted relative risk (aRR) = 1.12 (95% CI 0.60, 2.06)) and low libido (aRR = 1.70 (95% CI 0.91, 3.15)) compared to those with a HADS-A or HADS-D ≤ 8. Men with a HADS-A ≥ 8 were more likely to have a lower fTMSC on the day of oocyte retrieval (11.8 ≥ 8 vs 20.1 < 8, adjusted ß = -0.66 (95% CI -1.22, -0.10)). However, the LBR per embryo transfer (ET) was similar between the HADS-A groups (43.2% ≥8 vs 45.1% <8, adjusted relative risk = 0.90 (95% CI 0.65, 1.06)). Although depression was uncommon in the entire cohort, the HADS-D groups were clinically similar for fTMSC (18.7 ≥ 8 vs 16.0 < 8) and LBR per ET (46.7% ≥8 vs 45.4% <8). Limitations of our study are the survey-based design, the lack of sperm morphology assessment at the time of IVF, our inability to fully assess the HADS-D ≥ 8 cohort due to the small sample size and the large Caucasian demographic. Couples undergoing IVF have an increased likelihood of suffering from anxiety and/or depression. There is currently a debate on whether or not men should be treated with antidepressants while attempting to conceive due to potential detrimental effects on sperm quality. Our study shows that, regardless of antidepressant use, couples with men who did or did not report anxiety and/or depression have similar LBRs when undergoing IVF. Therefore, it is important to assess both partners for mental health and to not withhold treatment due to a concern about a potential impact of antidepressants or anxiety/depression on sperm quality. There was no funding to report for this study. Z.W. is a contributing author for UptoDate. S.S.S. is on the advisory board for Ferring Pharmaceuticals. E.G. was a medical consultant for Hall-Matson Esq, Teladoc, and CRICO and is a contributing author for UptoDate. The remaining authors have nothing to report. N/A.

Gamete Collection, Artificial Fertilization and Captive-Rearing of Eggs in a Terrestrial-Breeding Anuran with Parental Care: Alytes obstetricans.

The genus Alytes consists of six primitive terrestrial-breeding species (five of them endangered or present in restricted distributions) with unique male parental care. Alytes obstetricans was used as a model for the development of assisted reproductive technologies for gamete collection, artificial fertilization and captive-rearing of embryos. Sperm collection was achieved with human chorionic gonadotropin (hCG), but only 17 to 50% of males responded to the hormone. In addition, an effect of captivity on sperm quality was observed. A combination of gonadotropin-releasing hormone agonist (GnRHa) and hCG was tested for induction of ovulation, and 100% of females responded to the treatment. Recently collected sperm was used in artificial fertilization, and 10% of eggs showed complete embryo development. To design a method for captive-rearing of embryos, natural clutches (n = 13) were removed from males and divided into two sub-clutches. One was kept with all eggs together and in the other, the egg string was cut and eggs were split individually. All sub-clutches with eggs kept separated presented embryo survival (ranging from 27 to 61%) that hatched normally, while only one sub-clutch with embryos maintained together had some embryo survival (36%). These results may contribute to the management of this and related species.

Loss of ACTL7A causes small head sperm by defective acrosome-acroplaxome-manchette complex

BackgroundActin-like 7 A (ACTL7A) is essential for acrosome formation, fertilization and early embryo development. ACTL7A variants cause acrosome detachment responsible for male infertility and early embryonic arrest. In this study, we aim to explore the additional functions of ACTL7A beyond the process of acrosome biogenesis and investigate the possible underlying mechanisms.MethodsNuclear morphology analysis was used to observe the sperm head shape of ACTL7A-mutated patients. Actl7a knock-out (KO) mouse model was generated. Immunofluorescence and transmission electron microscopy (TEM) were performed to analyze the structure of spermatids during spermiogenesis. Tandem mass tags labeling quantitative proteomics strategy was employed to explore the underlying molecular mechanisms. The expression levels of key proteins in the pathway were analyzed by western blotting. Intracytoplasmic sperm injection (ICSI)-artificial oocyte activation (AOA) technology was utilized to overcome fertilization failure in male mice with a complete knockout of Actl7a.ResultsThe new phenotype of small head sperm associated with loss of ACTL7A in patients was discovered, and further confirmed in Actl7a-KO mice. Immunofluorescence and TEM analyses revealed that the deletion of ACTL7A damaged the formation of acrosome-acroplaxome-manchette complex, leading to abnormalities in the shaping of sperm heads. Moreover, a proteomic analysis of testes from WT and Actl7a-KO mice revealed that differentially expressed genes were notably enriched in PI3K/AKT/mTOR signaling pathway which is strongly associated with autophagy. Inhibition of autophagy via PI3K/AKT/mTOR signaling pathway activation leading to PDLIM1 accumulation might elucidate the hindered development of manchette in Actl7a-KO mice. Remarkably, AOA successfully overcame fertilization failure and allowed for the successful production of healthy offspring from the Actl7a complete knockout male mice.ConclusionsLoss of ACTL7A causes small head sperm as a result of defective acrosome-acroplaxome-manchette complex via autophagy inhibition. ICSI-AOA is an effective technique to rescue male infertility resulting from ACTL7A deletion. These findings provide essential evidence for the diagnosis and treatment of patients suffering from infertility.

Sığır embriyolarında 2G/3G cep telefonu sinyallerinin in vitro fertilizasyon, embriyo gelişimi ve cinsiyet dağılımı üzerine etkileri

During the thousand years of human evolution, the male to female ratio was practically equal, but it has recently changed in some way. The aim of this study was to investigate the effects of electromagnetic radiation from mobile phones on in vitro fertilization, embryo growth, and sex differentiation in cattle embryos. MII oocytes obtained from ovaries taken from slaughterhouse were used as research material. Gametes were exposed to electromagnetic fields by having a mobile phone inside the incubator that would periodically ring. On days 7 and 8, blastocyst development stages and embryo cleavage rates were evaluated. Additionally, the rates of cleavage for different time intervals after in vitro fertilization were noted. The sex determination of the embryos produced in vitro was determined by using polymerase chain reaction (PCR). As a result, it was found that exposure to radiofrequency electromagnetic fields could mainly reduce blastomere count, embryo diameter, and embryo quality rather than a having major adverse effect on the development of cattle embryos. Additionally, it was shown that exposure to electromagnetic fields appears to drastically reduce the chances of male survival.

Full-term live birth in a woman with 17α-hydroxylase and 17,20-lyase deficiency with assisted reproductive technology: a case report

Background17α-hydroxylase deficiency, which is caused by a CYP17A1 gene mutation, is a rare type of congenital adrenocortical hyperplasia that mainly manifests as hypertension, hypokalaemia and sexual dysplasia. To date, few pregnancies associated with this syndrome have been reported.Case presentationWe describe a 35-year-old Chinese woman with nonclassical congenital adrenal hyperplasia (NCCAH) due to 17α-hydroxylase/17,20-lyase deficiency who achieved pregnancy after in vitro fertilization (IVF) and frozen-thawed embryo transfer. She had secondary amenorrhea since she was 27, and subsequently, high level of progesterone in the follicular phase was found during a blood test. A compound heterozygous mutation was found in the CYP17A1 gene, c.1263G > A and c.985_987delinsAA. The patient was given standardized treatment with dexamethasone. Due to ovulation disorder, IVF was performed. She underwent whole embryo vitrification freezing. Frozen-thawed embryo transplantation was performed following the artificial cycle protocol of endometrium preparation, resulting in a singleton pregnancy. At 39 weeks and 1 day of gestation, caesarean section was performed due to the breech position of the foetus.ConclusionA high level of progesterone reduces endometrial receptivity. Standardized treatment with dexamethasone and frozen-thawed embryo transfer with an artificial cycle protocol of endometrium preparation should be the choice for infertile female patients with CYP17A1 deficiency.

Deoxyribonucleic acid test results in both paternity cases and assisted reproductions: rebuttals of the presumption of legitimacy under Section 165 of the “Nigerian Evidence Act”, 2011?

Section 165 of the Nigerian Evidence Act, 2011, presumes the legitimacy of a child given birth to during the existence of a valid marriage between the mother of such a child and any man, or within 280 days after the dissolution of any such marriage - if the mother remains unmarried after the dissolution of the marriage. Being a presumption, the legitimacy of such a child may be displaced upon adducing credible evidence to prove that the child is not fathered by the man during the continuance of the marriage or within 280 days immediately after the dissolution of the marriage. This Article therefore, discusses the use of Deoxy Ribonucleic Acid tests results to rebut the presumption of legitimacy in Section 165 of the Evidence Act using paternity cases and In Vitro Fertilization of embryos, particularly where there are medical mistakes or malpractices by clinicians and embryologists. Keywords: Deoxyribonucleic Acid; Paternity; In Vitro Fertilization; Presumption; Evidence Act

Correlation between abnormal energy metabolism of ovarian granulosa cells and in vitro fertilization–embryo transfer outcomes in patients with polycystic ovary syndrome and obesity

ContextGranulosa cells (GCs) that surround oocytes in mammalian reproduction play an active role in oocyte differentiation through proliferation and energy production.AimsThis study aimed to investigate the characteristics of the energy metabolism of ovarian GCs and the influence of GCs on the early embryonic development in polycystic ovary syndrome (PCOS).MethodsThe clinical characteristics and in vitro fertilization-embryo transfer treatment outcomes of 39 patients with PCOS and 68 patients with simple tubal factor infertility who underwent controlled ovarian hyperstimulation were analyzed and summarized. The mitochondrial function and glucose metabolism level of the GCs were determined, as well as the content of oxidative stress markers in the follicular fluid (FF) of patients with and without PCOS.Key resultsWhen compared to the non-PCOS group, patients with PCOS had a significantly increased number of retrieved oocytes but a significantly decreased number of high-quality embryos, available embryos, and high-quality blastocyst formation (P < 0.05). Furthermore, the mitochondrial membrane potential, adenosine triphosphate level, and mitochondrial DNA (mtDNA) copy number decreased in the GCs, whereas the levels of reactive oxygen species increased (P < 0.01). The levels of malondialdehyde and 8-oxo-deoxyguanosine (8-OHdG) in the follicular fluid (FF) of the patients with PCOS were higher than those of the control group (P < 0.05), and superoxide dismutase was increased by compensation (P < 0.05). In the PCOS group, the expressions of GLUT1, LDHA, and PFKP were lower than those in the non-PCOS group, and glucose levels were higher.ConclusionsThe low oocyte competence of PCOS may be associated with mitochondrial dysfunction and abnormal glycolysis.ImplicationsThis research offers explanations for the possible connections influencing human ovarian folliculogenesis.

How the Oviduct Lipidomic Profile Changes over Time after the Start of an Obesogenic Diet in an Outbred Mouse Model.

We investigated whether a high-fat/high-sugar (HF/HS) diet alters the lipidomic profile of the oviductal epithelium (OE) and studied the patterns of these changes over time. Female outbred Swiss mice were fed either a control (10% fat) or HF/HS (60% fat, 20% fructose) diet. Mice (n = 3 per treatment per time point) were sacrificed and oviducts were collected at 3 days and 1, 4, 8, 12 and 16 weeks on the diet. Lipids in the OE were imaged using matrix-assisted laser desorption ionisation mass spectrometry imaging. Discriminative m/z values and differentially regulated lipids were determined in the HF/HS versus control OEs at each time point. Feeding the obesogenic diet resulted in acute changes in the lipid profile in the OE already after 3 days, and thus even before the development of an obese phenotype. The changes in the lipid profile of the OE progressively increased and became more persistent after long-term HF/HS diet feeding. Functional annotation revealed a differential abundance of phospholipids, sphingomyelins and lysophospholipids in particular. These alterations appear to be not only caused by the direct accumulation of the excess circulating dietary fat but also a reduction in the de novo synthesis of several lipid classes, due to oxidative stress and endoplasmic reticulum dysfunction. The described diet-induced lipidomic changes suggest alterations in the OE functions and the oviductal microenvironment which may impact crucial reproductive events that take place in the oviduct, such as fertilization and early embryo development.

Flat mount preparation for whole-mount fluorescent imaging of zebrafish embryos.

The zebrafish is a widely used model organism for biomedical research due to its ease of maintenance, external fertilization of embryos, rapid embryonic development, and availability of established genetic tools. One notable advantage of using zebrafish is the transparency of the embryos, which enables high-resolution imaging of specific cells, tissues, and structures through the use of transgenic and knock-in lines. However, as the embryo develops, multiple layers of tissue wrap around the lipid-enriched yolk, which can create a challenge to image tissues located deep within the embryo. While various methods are available, such as two-photon imaging, cryosectioning, vibratome sectioning, and micro-surgery, each of these has limitations. In this study, we present a novel deyolking method that allows for high-quality imaging of tissues that are obscured by other tissues and the yolk. Embryos are lightly fixed in 1% PFA to remove the yolk without damaging embryonic tissues and are then refixed in 4% PFA and mounted on custom-made bridged slides. This method offers a simple way to prepare imaging samples that can be subjected to further preparation, such as immunostaining. Furthermore, the bridged slides described in this study can be used for imaging tissue and organ preparations from various model organisms.

Ameliorative effect of Stevia rebaudiana Bertoni on sperm parameters, in vitro fertilization, and early embryo development in a streptozotocin-induced mouse model of diabetes.

Diabetes mellitus (DM) is a common metabolic disease characterized by high blood sugar levels. It is well known that men with diabetes frequently experience reproductive disorders and sexual dysfunction. In fact, sperm quality has a significant effect on fertilization success and embryo development. The current study aimed to investigate the effect of Stevia rebaudiana hydroalcoholic extract on serum testosterone levels, sperm parameters, in vitro fertilization (IVF) success, and in vitro embryonic developmental potential to reach the blastocyst stage in a streptozotocin (STZ)-induced mouse model of diabetes. In this research, 30 male mice were distributed randomly into control, diabetic (streptozotocin 150 mg/kg) and diabetic + Stevia (400 mg/kg) groups. The results revealed a decrease in body and testis weight and elevated blood fasting blood sugar (FBS) levels in the diabetic group, compared with the control. However, Stevia treatment significantly increased body and testis weight, while serum FBS levels were decreased compared with the diabetic group. In addition, Stevia significantly increased blood testosterone levels compared with the diabetic group. Moreover, sperm parameters were improved considerably by Stevia treatment compared with the diabetic group. Furthermore, Stevia administration significantly promoted IVF success rate and in vitro development of fertilized oocytes compared with the diabetic group. In summary, our data indicated that Stevia enhanced sperm parameters, IVF success, and in vitro embryonic developmental competency in diabetic mice, probably because of its antioxidant effects. Therefore, Stevia could ameliorate sperm parameters that, in turn, increase fertilization outcomes in experimental-induced diabetes.

Ovum Pick Up (OPU) and in vitro embryo production in pregnant cows (Bos Indicus) at the Bachigualatito rancho, la Trinitaria, Chiapas

With the objective of determining the production, quality and development of bovine embryos (Bos Indicus), oocytes were collected from 14 females distributed in two groups: empty females (T1; n=7) and an experimental group of pregnant females (T2; n=7). The two groups were subjected to Ovum Pick Up (OPU) using disposable 18-gauge needles and a vacuum pressure of 100 mmHg. to later carry out in vitro fertilization (IVF). The study variables were the number of oocyte aspirated and fertilized and the expected embryos. A Wilcoxon test was performed for non-parametric data between two groups, finding no significant differences between treatments P&gt; 0.05. 250 oocytes were recovered by fertilizing out of 190, obtaining a fertilization rate of 77%, reaching a transferrable blastocyst rate of 24% (45/190). In empty females (7), 113 oocytes were obtained, reaching a fertilization rate of 75% (81/113) and 25% transferable blastocysts (18/81). In the 7 pregnant females, 137 oocytes were collected, reaching a fertilization rate of 83% (109/137) and 23% transferable blastocysts (27/109). Follicular aspiration for in vitro fertilization of embryos from pregnant and empty cows is viable without differences between them, but being more variable in pregnant cows.

P-119 Relation of graphical follicle models to the cumulative live birth rate in GnRH-antagonist stimulation treatment cycles

Abstract Study question Is it possible to create a model that combines follicle number and size to help physicians visualize the trigger requirements to predict oocyte utilization? Summary answer Findings support graphical follicle model as an innovative, simple, and practiced parameter for predicting clinical results in ovary stimulation treatment and facilitating personalized protocol adjustment. What is known already Previous studies have observed the number and size of follicles are two independent indicators of whether the oocyte is adequate and mature and are used to predict the trigger time in routine clinical practice. However, due to individualized differences, it currently relies mainly on physician experience. Study design, size, duration This retrospective study included 8405 patients started their first in vitro fertilization cycle with a GnRH-ant protocol including fresh and subsequent frozen-thawed cycles during 2016–2020. Participants/materials, setting, methods We classified follicles recorded on the HCG day by size. We then produced graphical models, and classified into Inverted-trapezoid (large follicles in dominant proportion), Polygon (moderate follicles in dominant proportion), Trapezoid (small follicles in dominant proportion), Rectangle (equivalent proportions of the three size categories). The Cochran–Mantel–Haenszel and Generalized Linear Model(GLM) were used to evaluate the difference among models in relation to maturity, fertilization, and number of viable embryos, as well as cumulative live birth rate. Main results and the role of chance In GLM analysis, after adjusting the confounders, there are differences between models of CLBR. The CLBR of the different models was higher in the Polygon and Inverted-trapezoid model than Trapezoid and Rectangle model (42.75%, 39.56%, vs. 37.38%, 28.57%, respectively; all P&amp;lt;0.05). For oocytes derived from very large follicles ( &amp;gt; 20 mm), the CLBR was lower than that of patients with ≤ 20 mm follicles [26.10% vs. 42.10%, OR = 1.74 (95% confidence interval 1.52–2.00), P&amp;lt;0.01] in Inverted-trapezoid model, but there was no difference between models. And the risk of ovarian hyperstimulation syndrome (OHSS) rate of patients with ≤ 20 mm follicles was lower than that of patients with &amp;gt; 20 mm follicles [8.64% vs. 17.89%, OR = 0.57 (95%CI: 0.49−0.65), P&amp;lt;0.01] in Inverted-trapezoid model. Patients who received an adjusted Gn dose(whether Decreased or Increased-dose protocol) showed no difference in CLBR among models (Polygon vs Inverted-trapezoid vs Trapezoid vs Rectangle model: 47.07% vs. 49.21% vs. 47.69% vs. 42.42%, P &amp;gt; 0.05); but when patients continued with the same starting dose in Fixed-dose protocol, the CLBR of the Polygon model was higher than that of other models (40.43% vs. 34.32, 31.13% vs. 26.46%, respectively; all P value &amp;lt;0.05). Limitations, reasons for caution This study is retrospective. Due to analysis of real-world data, the follicular corresponding outcome following measurement was not obtained. Besides, the majority of patients received 2 cleavage stage embryos transfer, this approach may impact the external validity of follicle model. Wider implications of the findings The follicle models can demonstrate ovarian response of patients. It is better for patients to reach the Inverted-trapezoid model with dominate follicles &amp;gt; 18 mm and &amp;lt;20 mm. Adjusting the protocol is critical to the outcome. But how to improve follicle models by regulating stimulation remains to be further studied. Trial registration number not applicable

P-258 In-vitro oocyte maturation (IVM) in the ART clinic – What can we learn from our failed cycles?

Abstract Study question Why do some IVM cycles remain unsuccessful? Which factors contribute to failure in producing a usable embryo in IVM cycles? Summary answer Failure to obtain usable embryos after IVM was associated with oocyte dysfunction, inappropriate patient selection and unanticipated low oocyte yield. What is known already In-vitro maturation of oocytes retrieved from antral follicles has been offered as a mild-ART-approach to subfertile women with increased functional ovarian reserve, ovarian resistance to gonadotropins and in the context of fertility preservation. When using monophasic IVM culture systems, oocyte maturation, embryological development and pregnancy outcomes are generally lower compared to conventional ART (cART). Women who yield high numbers of cumulus oocyte complexes from a single egg retrieval procedure, such as those with polycystic ovary syndrome (PCOS), have been considered the best candidates for IVM, to compensate for the lower maturation rate and lower embryo yield from IVM cycles. Study design, size, duration This was a single-tertiary center, retrospective cohort study between May 2018 and February 2022 including 277 patients: 53 patients with failed IVM and 224 patients with a successful IVM cycle (inter-patient analysis). All ART cycles from patients with one failed IVM were investigated (intra-patient analysis). Failed IVM cycles were grouped: (i) ≤20% oocyte maturation; (ii) fertilization failure; (iii) embryo development failure. Patients with FSH resistance, fertility preservation or egg donation were excluded. Participants/materials, setting, methods Only patients with AMH &amp;gt;2.27 ng/ml were included. Oocytes retrieved in minimally stimulated non-hCG triggered IVM cycles were matured in a monophasic IVM system. Embryos were vitrified at cleavage stage and transferred in a hormonally substituted (HRT) cycle. Baseline patient characteristics, endocrinology and embryological data were analyzed. Intra-patient analysis was done using all ART cycles (failed IVM, IVM and cART) performed in one patient. Main results and the role of chance Inter-patient analysis revealed similar age, BMI and free testosterone, whereas AMH was lower in patients with a failed cycle (8.8 ± 3.5 vs 10.9 ± 6.4 ng/mL, p = 0.03). As expected, maturation, fertilization and useable embryos differed significantly in failed vs successful cycles: respectively 31% vs 48%; 40% vs 65%; 0% vs 50%; p &amp;lt; 0.0001. Out of 53 patients with a failed IVM cycle, 6 had oocyte maturation problems, 11 had failed fertilization and 36 had impaired embryological development. Intra-patient analysis revealed that in the failed oocyte maturation group, 2/6 patients had maturation problems that persisted in cART cycles, indicating oocyte dysfunction. Similarly, recurrent fertilization failure was noted in 3/11 patients, due to insufficient sperm quality (n = 2). In 8/36 patients, insufficient embryo quality was observed both after IVM and cART. Hence 13/53 (24.5%) failed IVM cycles were attributed to intrinsic patient characteristics. A subgroup of patients with a failed IVM cycle had normal maturation (3/6), fertilization (7/11) or good embryos (18/36) in other IVM or cART cycles. Factors associated with cycle failure included technical issues during egg retrieval resulting in unanticipated low oocyte yield (n = 14/40), and suboptimal inclusion criteria (no PCOS, n = 3/40). Limitations, reasons for caution This was a retrospective study and holds the possibility of unmeasured confounding factors. Wider implications of the findings Risk factors for IVM failure should be identified (e.g. non-PCOS, poor operator experience) and any underlying intrinsic patient conditions should be managed within a multi-disciplinary team. Optimal patient selection is key. Analysis of failed cycles helps clinicians to estimate the prognosis of future ART cycles in women with elevated AMH. Trial registration number not applicable

P-259 Intracytoplasmic sperm injection conducted within a micro 3D printed device that requires no holding pipette or vacuum reduces porcine oocyte invagination during microinjection

Abstract Study question Can the use of a custom-designed and 3D printed microICSI™ device reduce the degree of oocyte invagination during intracytoplasmic sperm injection (ICSI)? Summary answer Invagination was significantly less in porcine oocytes when ICSI was performed in microICSI™ device compared to conventional ICSI. What is known already ICSI is a difficult procedure for embryologists to master, yet until recently, technically little had changed. In particular, the holding pipette (HP) with vacuum to hold the oocyte has not been surpassed. However, a source of shear-stress during ICSI of oocytes is the invagination of the zona pellucida and cytoplasm that occurs during microinjection, due to the pressure of the injection pipette against the small surface area of the HP. A recent study demonstrated microinjection within a two-piece 3D printed device. Here we evaluated a design refinement that displaced injection pressure more evenly across the oocyte to improve embryo quality. Study design, size, duration A control (conventional ICSI) and study group (microICSI™) were compared over three replicates investigating the level of invagination (3-point score, 1 is lowest and 3 is greatest) during ICSI. Incidence of cytoplasmic lysis was also recorded 24 h following ICSI. Participants/materials, setting, methods Porcine oocytes collected by follicle aspiration of abattoir-sourced ovaries were matured for 39-44 h in NCSU-17 medium supplemented with eCG, hCG, porcine follicular fluid, EGF and insulin. Mature oocytes, stripped of cumulus, were randomly allocated to either conventional ICSI or microICSI™. ICSI was performed, with treatment order randomised, and the injected oocytes were cultured in NCSU-17 culture medium at 39 C. Main results and the role of chance The microICSI™ device was modelled as a one-piece structure with contoured surfaces within a microwell array to support the oocyte during injection without the requirement for a holding pipette. Two-photon polymerisation 3D micro printing was used to print and assess multiple prototype geometries to optimise the support of the oocyte during ICSI. Over the three replicates (n = 10-20/treatment/replicate), the degree of invagination was consistently lower in the microICSI™ group compared with conventional ICSI (Mean ± SEM): Replicate 1: 1.40 ± 0.16 vs. 2.00 ± 0.19; Replicate 2: 1.20 ± 0.11 vs. 2.00 ± 0.13; Replicate 3: 1.42 ± 0.12 vs. 1.78 ± 0.15, with a paired t-test showing a significant difference between the two groups (p = 0.035). The incidence of lysis was not significantly different between the two treatments (ranging from 15-20% across both groups and varied between replicates). Limitations, reasons for caution The use of a porcine ICSI model may not sufficiently replicate what occurs with human ICSI as human oocytes experience greater levels of invagination (typically scored out of 4 rather than 3). Wider implications of the findings Reducing the invagination due to the injection process may reflect a less stressful procedure, with improvement to fertilization rates and embryo quality. Trial registration number not applicable

P-677 Letrozole inhibits ovulation via reducing responsiveness to luteinizing hormone in in vitro-grown mouse follicles

Abstract Study question Does letrozole reduce responsiveness to luteinizing hormone (LH) in in vitro-grown mouse follicles? Summary answer We found that letrozole reduced responsiveness to LH via reducing of luteinizing hormone/chorionic gonadotropin receptor (Lhcgr) transcription in in vitro. What is known already The continuous dosing of letrozole, the third-generation aromatase inhibitor, is used for the controlled ovarian stimulation (COS) of fertility preservation cycles in women with hormone-sensitive breast cancer to prevent the transient rise of serum estrogen levels. Recently, lower oocyte maturation rates and higher abnormal fertilization rates in COS with letrozole compared to standard COS have been reported. The studies using aromatase knockout mice and estrogen receptor beta knockout mice showed that intra-follicular estrogen is essential for responsiveness to LH of granulosa cells. However, whether letrozole reduces responsiveness to LH of follicles remains unknown. Study design, size, duration We evaluated the effect of letrozole on responsiveness to LH using in vitro mouse follicle culture system. Preantral follicles (150-200 µm) with a small number of stromal cells were isolated from 3 weeks old C57BL/6jjcl mouse ovaries and cultured in the presence of letrozole. We analyzed in vitro ovulation ability, and expression levels of ovulation-related genes to clarify the effect of letrozole on responsiveness to LH of follicles. Participants/materials, setting, methods The follicles were cultured with letrozole (0.01µM, 0.1µM, or 1µM) or vehicle (0.1% DMSO) for 5 days followed by 5 IU/ml hCG and 5 ng/ml hEGF stimulation as ovulation induction. The diameter and survival rate of follicles were assessed. After16 hours after ovulation induction, we assessed the ovulation and measured the transcription of Lhcgr, Ptgs2, Runx1 and Actb (internal control) in the follicles by RT-qPCR. We conducted a collateral experiment in the presence of estradiol. Main results and the role of chance The follicle growth and survival rate did not change by letrozole in vitro. However, in vitro ovulation was reduced by the addition of letrozole in a dose-dependent manner (Cochran-Armitage trend test, P &amp;lt; 0.0001): 41.2% in the 0.01µM letrozole treated group (n = 23), 10.5% in the 0.1µM letrozole treated-group (n = 17), and no ovulation in the 1µM letrozole treated-group (n = 19) compared with 69.6% in the vehicle-group (n = 18). Exogenous estrogen addition restored the ovulation ability of 1µM letrozole-treated follicle to the same levels as the vehicle group. RT-qPCR revealed that 0.1 µM letrozole significantly reduce the transcription levels of Lhcgr (P = 0.0027), Runx1 (P = 0.0124), and Ptgs2 (P = 0.0067) compared with vehicle-treated follicles. Exogenous estrogen addition restored the transcription of these genes to levels observed in vehicle-treated follicles. We also observed a positive correlation between the transcription of Lhcgr and Ptgs2 (R = 0.55, P = 0.0003), Lhcgr and Runx1 (R = 0.71, P &amp;lt; 0.0001), and Ptgs2 and Runx1 (R = 0.77, P &amp;lt; 0.0001). Our results suggested that letrozole-treated follicles impaired ovulation due to dysregulation of Lhcgr transcription and its downstream cascade caused by estrogen deficiency. Limitations, reasons for caution This is an in vitro experiment using a mouse model. Further research is needed to determine whether our findings are applicable to humans. Wider implications of the findings Our findings imply that letrozole may have disadvantages in not only ovulation, but also subsequent reproductive processes affected by the effectiveness of the LH surge, such as oocyte maturation, fertilization, and preimplantation embryo development. When evaluating oocyte cryopreservation for fertility preservation, it may be necessary to consider the COS protocol. Trial registration number Not applicable