The utility of human two plus one small pronucleated zygotes (2.1PN) based on clinical outcomes and the focused ploidy analysis.

PURPOSE: Are human embryos arising from two plus one small pronucleated zygotes, called 2.1 pronuclei (PN), clinically useful? METHODS: In a retrospective embryo cohort study and prospective experimental study, a total of 287 cycles in which at least one 2.1PN was identified in the fertilization check were included. Embryonic development and clinical outcome were compared for the 1395 2PN zygotes and 304 2.1PN zygotes that were siblings. All embryos were individually cultured in time-lapse systems. Twenty-five 2.1PN-derived blastocysts, donated for research, were used in focused single-nucleotide variant ploidy analysis to identify the distribution pattern of heterozygosity. RESULTS: The average diameter of PN was 24.9 ± 2.4 µm for large PN and 10.2 ± 2.4 µm for small PN; 79.9% of small PN was derived from female pronuclei. Blastocyst formation rate and good-quality blastocyst rate were significantly lower with 2.1PN embryos than with 2PN embryos (40.0% vs. 57.7%, 21.4% vs. 33.5%, respectively). A total of 13 embryos derived from 2.1PN were transferred, and three healthy babies were born. In ploidy constitutions of trophectoderm (TE), 2.1PN-derived blastocyst TE was shown to be mostly diploid (95.8%, 23/24), and only one blastocyst showed triploid. CONCLUSIONS: It was suggested that 2.1PN embryos have lower embryonic developmental potential than 2PN embryos, but most of the 2.1PN were diploid, indicating that they are likely to be clinically usable. It is recommended to perform embryo transfer following a combination of PGT-A and ploidy analysis.

Micromapping testicular sperm extraction: A new technique for microscopic testicular sperm extraction in nonobstructive azoospermia.

Purpose: In microscopic testicular sperm extraction (mTESE) for nonobstructive azoospermia (NOA), sperm can be recovered relatively easily in some cases, and mTESE may be retrospectively considered excessive. However, mTESE is routinely performed in the majority of NOA patients because of the difficulty in predicting tissue status. A minimally invasive and comprehensive sperm retrieval method that allows on-the-spot tissue assessment is needed. We have developed and evaluated a novel sperm retrieval technique for NOA called micromapping testicular sperm extraction (MMTSE). Methods: MMTSE involves dividing the testis into four sections and making multiple small needle holes in the tunica albuginea to extract seminiferous tubules and retrieve sperm. The sperm-positive group by MMTSE (Group I) underwent additional tissue collection (ATC) via a small incision, whereas the sperm-negative group by MMTSE (Group 0) underwent mTESE. Results: In total, 40 NOA participants underwent MMTSE. Group I included 15 patients and Group 0 included 25 patients. In Group 1, sperm were recovered from all patients by ATC. In Group 0, sperm were recovered in 4 of 25 cases using mTESE. Conclusions: MMTSE shows promise as a simple method that comprehensively searches testicular tissue and retrieves sperm using an appropriate method while minimizing patient burden.

Clinical outcomes of personalized blastocyst embryo transfer after endometrial receptivity analysis: A multicenter, retrospective cohort study.

Purpose: To evaluate clinical outcomes after endometrial receptivity analysis (ERA). Methods: This was a multicenter, retrospective cohort study involving 861 women who underwent ERA testing at certified fertility clinics in Japan, and who received subsequent personalized blastocyst embryo transfers (ET) between 2018 and 2020. Clinical outcomes, including pregnancies, miscarriages, and live births, were evaluated according to receptivity status for ERA. Results: Mean patient age was 37.7 years (SD = 4.0), and the median number of previous ETs was 2 (interquartile range, 2-3). 41.0% (353/861) of patients were non-receptive for ERA testing. Clinical pregnancy, miscarriage, and live birth rates for personalized blastocyst ET were 44.5% (226/508), 26.1% (59/226), and 26.8% (136/508) for receptive patients, and 43.1% (152/353), 28.3% (43/152), and 28.9% (102/353) for non-receptive patients, all statistically nonsignificant. Multiple logistic regression demonstrated similar nonsignificant associations between receptivity and clinical outcomes. Greater patient age, smoking, and longer duration of infertility were significantly and negatively associated with receptivity, whereas a history of delivery was positively associated and statistically significant. Conclusions: Clinical outcomes after ERA testing were similar between receptive and non-receptive patients. Further prospective study including an appropriate comparison group are warranted to evaluate the efficacy of ERA testing.

Non-medical oocyte cryopreservation at a single center in Japan: 8 years of experience.

Purpose: Increasing numbers of women are opting to undergo non-medical oocyte cryopreservation (NMOC). In this report, we present experience at our clinic and discuss NMOC in Japan. Methods: We followed the progress of 403 women who underwent NMOC at our clinic between 2014 and 2021, totaling 592 reproductive cycles. Results: In total, 61 women underwent oocyte warming and fertility treatment. Of these, 13 women gave birth to 14 children. The median age at first oocyte cryopreservation was 38.3 years, and the oldest pregnant woman was 42 years. Most clients (60%) were in their late 30s. The median time between first oocyte cryopreservation and warming was 3.0 years. One woman was able to achieve a live birth with four vitrified oocytes. Conclusions: This is the first report in Japan documenting pregnancies and childbirths resulting from NMOC. Ideally, women hope to achieve natural pregnancy between 20 and 32 years of age. NMOC is an option for individuals who are unable to pursue pregnancy during optimal reproductive years and wish to preserve their fertility for future attempts. NMOC is recommended in cases with few indications, and it is necessary to continue accumulating data on its long-term safety and effectiveness.

Chlormadinone acetate in progestin-primed ovarian stimulation does not negatively affect clinical results.

Purpose: To investigate whether progestin-primed ovarian stimulation (PPOS) with chlormadinone acetate (CMA) adversely affects clinical results and neonatal outcomes, or causes congenital deformities. Methods: This retrospective study was conducted at private IVF clinic from November 2018 to November 2021. Women underwent oocyte retrieval using gonadotropin-releasing hormone (GnRH) antagonist protocol (n = 835) or PPOS protocol (n = 57) were included. Eligible patients were normal ovarian responders (aged <40, AMH ≧1.0 ng/mL) with freeze-all cycle. Embryo developments, clinical results, or neonatal outcomes of singletons derived from transfer of frozen single blastocysts were compared within each group. Results: Patient characteristics were similar in both groups. The median LH level (mIU/mL) at trigger in the GnRH antagonist group [2.0 (1.2-3.7)] was significantly higher than in the PPOS group [0.9 (0.3-1.7)]. There was no cycle with premature LH surge in the PPOS group. Fertilization and blastocyst formation rates did not differ significantly between groups. Furthermore, clinical outcomes were also similar in the two groups. Congenital abnormality rates did not differ significantly [0.9% (3/329), 0.0% (0/17)]. Conclusions: CMA using ovarian stimulation did not negatively affect clinical results. Our data suggest that PPOS with CMA is an appropriate ovarian stimulation method for normal ovarian responders.

Creation, effects on embryo quality, and clinical outcomes of a new embryo culture medium with 31 optimized components derived from human oviduct fluid: A prospective multicenter randomized trial.

Purpose: Our aim is to make an ideal embryo culture medium close to human oviduct fluid (HOF) components, and to evaluate the quality of this medium with embryo quality and clinical outcomes in assisted reproductive technology (ART) by a prospective randomized controlled trial (RCT). Methods: Study I: HOF was collected laparoscopically from patients (n = 28) with normal pelvic findings. According to HOF analysis results, the new medium "HiGROW OVIT®" (OVIT) was designed. Study II: Embryos (2 pronuclei (2PN) = 9633) were assigned from 1435 patients. The blastulation rate (BR), good BR (gBR), utilized (transferred/cryo-preserved) BR (uBR), pregnancy rate (PR), and miscarriage rate (MR) were compared between the OVIT and control groups by RCT. Results: The novel medium 'OVIT' was produced according to 31 HOF components. The concentrations of essential amino acids (e-AAs) were lower in OVIT than in current media, yet the opposite was true for ne-AA concentrations. gBR and uBR were higher in the OVIT group than in the control group. In the older female group, gBT and uBR were significantly higher in the OVIT group. Conclusions: The novel medium 'OVIT' was produced according to HOF data. The OVIT had significantly better embryo quality and clinical outcomes than the current media.

Six-year follow-up of children born from vitrified oocytes.

RESEARCH QUESTION: Are children born from vitrified-warmed oocytes physically or mentally different from naturally conceived children? DESIGN: Intracytoplasmic sperm injection (ICSI) of vitrified-warmed oocytes was performed for 282 patients (307 cycles) from August 2000 to March 2020. Long-term follow-up of children born from vitrified-warmed oocytes was performed via a questionnaire that was sent to the parents at regular intervals from 3 to 72 months after the child's birth. Questionnaires were sent 11 times from birth to the age of 6 years. The development of motor function and mental status was evaluated as the primary outcome, based on the reported data. Subsequently, patients were divided into four groups by age at oocyte retrieval (20-29, 30-34, 35-39, and 40 years or older). Clinical outcomes were calculated as a secondary outcome. RESULTS: For the 282 patients, the birth of 116 babies was reported (110 singletons and three sets of twins), and seven cases are, at the time of writing, unconfirmed. The results of the survey found physical parameters in singletons to be equivalent to the nationally reported average data issued by the Ministry of Health, Labor and Welfare of Japan. CONCLUSION: This is the first follow-up report of children born from vitrified-warmed oocytes followed by ICSI. The data suggested that the responses from the study participants on the mental and physical development of children were comparable to the data reported by the government, although more responses from patients should be collected to allow further study.

Y chromosome microdeletion screening using a new molecular diagnostic method in 1030 Japanese males with infertility.

The azoospermia factor (AZF) region is important for spermatogenesis, and deletions within these regions are a common cause of oligozoospermia and azoospermia. Although several studies have reported this cause, the present research, to the best of our knowledge, is the first large-scale study assessing this factor in Japan. In this study, 1030 male patients with infertility who were examined for Y chromosome microdeletion using the polymerase chain reaction-reverse sequence-specific oligonucleotide (PCR-rSSO) method, a newly developed method for Y chromosome microdeletion screening, were included. The study enrolled 250 patients with severe oligospermia and 717 patients with azoospermia. Among the 1030 patients, 4, 4, 10, and 52 had AZFa, AZFb, AZFb+c, and AZFc deletions, respectively. The sperm recovery rate (SRR) of microdissection testicular sperm extraction in patients with AZFc deletions was significantly higher than that in those without AZF deletions (60.0% vs 28.7%, P = 0.04). In patients with gr/gr deletion, SRR was 18.7%, which was lower than that in those without gr/gr deletion, but was not statistically significant. In conclusion, our study showed that the frequency of Y chromosome microdeletion in male patients in Japan was similar to that reported in patients from other countries, and SRR was higher in patients with AZFc deletion.

Does dysbiotic endometrium affect blastocyst implantation in IVF patients?

PURPOSE: To analyze the pregnancy outcomes of IVF patients presenting eubiotic or dysbiotic endometrium at the time of embryo transfer and to analyze what bacterial profiles are suitable for embryo implantation. METHODS: Ninety-nine IVF patients under 40 years old undergoing vitrified-warmed blastocyst transfer in HRT cycle had concurrent endometrial microbiome analysis. Samples from the endometrium were taken from the participants at the time of mock transfer; the bacterial profiles at genus level and percentage of lactobacilli in the endometrium of the patients were analyzed. RESULTS: Thirty-one cases (31.3%) had dysbiotic endometrium. The background profiles, pregnancy rates per transfer (52.9% vs 54.8%), and miscarriage rates (11.1% vs 5.9%) were comparable between patients with eubiotic or dysbiotic endometrium. Major bacterial genera other than Lactobacillus detected in the dysbiotic endometrium were Atopobium, Gardnerella, and Streptococcus. Some patients achieved ongoing pregnancies with 0% Lactobacillus in the endometrium. The endometrial bacterial profiles of pregnant cases with dysbiotic endometrium were comparable with those of non-pregnant cases. CONCLUSION: Analyzing microbiota at the species-level resolution may be necessary for identifying the true pathogenic bacteria of the endometrium and avoiding over-intervention against non-Lactobacillus microbiota. Further studies are necessary for analyzing the mechanism of how the pathogenic bacteria affect embryo implantation.

Association of four imprinting disorders and ART.

BACKGROUND: Human-assisted reproductive technologies (ART) are a widely accepted treatment for infertile couples. At the same time, many studies have suggested the correlation between ART and increased incidences of normally rare imprinting disorders such as Beckwith-Wiedemann syndrome (BWS), Angelman syndrome (AS), Prader-Willi syndrome (PWS), and Silver-Russell syndrome (SRS). Major methylation dynamics take place during cell development and the preimplantation stages of embryonic development. ART may prevent the proper erasure, establishment, and maintenance of DNA methylation. However, the causes and ART risk factors for these disorders are not well understood. RESULTS: A nationwide epidemiological study in Japan in 2015 in which 2777 pediatrics departments were contacted and a total of 931 patients with imprinting disorders including 117 BWS, 227 AS, 520 PWS, and 67 SRS patients, were recruited. We found 4.46- and 8.91-fold increased frequencies of BWS and SRS associated with ART, respectively. Most of these patients were conceived via in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), and showed aberrant imprinted DNA methylation. We also found that ART-conceived SRS (ART-SRS) patients had incomplete and more widespread DNA methylation variations than spontaneously conceived SRS patients, especially in sperm-specific methylated regions using reduced representation bisulfite sequencing to compare DNA methylomes. In addition, we found that the ART patients with one of three imprinting disorders, PWS, AS, and SRS, displayed additional minor phenotypes and lack of the phenotypes. The frequency of ART-conceived Prader-Willi syndrome (ART-PWS) was 3.44-fold higher than anticipated. When maternal age was 37 years or less, the rate of DNA methylation errors in ART-PWS patients was significantly increased compared with spontaneously conceived PWS patients. CONCLUSIONS: We reconfirmed the association between ART and imprinting disorders. In addition, we found unique methylation patterns in ART-SRS patients, therefore, concluded that the imprinting disorders related to ART might tend to take place just after fertilization at a time when the epigenome is most vulnerable and might be affected by the techniques of manipulation used for IVF or ICSI and the culture medium of the fertilized egg.

A pilot study and case reports on endometrial microbiota and pregnancy outcome: An analysis using 16S rRNA gene sequencing among IVF patients, and trial therapeutic intervention for dysbiotic endometrium.

PURPOSE: The present study aimed to analyze the pregnancy outcomes of IVF patients presenting Lactobacillus-dominated microbiota (LDM) or non-Lactobacillus-dominated microbiota (NLDM) of their endometrium and to report cases who were treated for NLDM concurrently with antibiotics and prebiotic/probiotic supplements in a Japanese infertile population. METHODS: Ninety-two IVF patients were recruited from August 2017 to March 2018. Endometrial fluid samples for sequencing were collected using an IUI catheter. The bacterial status of the endometrium and the pregnancy outcomes were analyzed. For cases with NLDM, antibiotics and prebiotics/probiotics were administered according to their individual microbial conditions. RESULTS: Forty-seven cases (51.1%) presented LDM and 45 cases (48.9%) presented NLDM at initial analysis. Nine Patients with NLDM were treated by antibiotics and prebiotics/probiotics, and successfully became Lactobacillus-dominant. Pregnancy rates by single vitrified-warmed blastocyst transfers were higher in the LDM group (58.9% per patient and 36.3% per FBT) than in the NLDM group (47.2% per patient and 34.7% per FBT) but not significantly different. CONCLUSION: The results of this study could not necessarily prove the clear benefit of establishing Lactobacillus-dominated endometrium in terms of pregnancy outcome, but there is significance in searching for endometrial microbial status of infertile patients and recovering Lactobacillus-dominated endometrium might benefit implantation.

Analysis of endometrial microbiota by 16S ribosomal RNA gene sequencing among infertile patients: a single-center pilot study.

PURPOSE: The present study aimed to analyze the endometrial and vaginal microbiome among a Japanese infertile population by sequencing and the impact of the endometrial and vaginal environment on implantation. METHODS: In total, 102 infertile (79 in vitro fertilization [IVF] and 23 non-IVF) patients and seven healthy volunteers were recruited from August to December, 2017. Endometrial fluid and vaginal discharge samples for sequencing were collected by using an intrauterine insemination catheter. The bacterial status of the endometrium and vagina were analyzed. RESULTS: The Lactobacillus-dominated microbiota (>90% Lactobacillus spp.) in the endometrium vs vagina was 38% (30/79) vs 44.3% (44/79) in the IVF patients, 73.9% (17/23) vs 73.9% (17/23) in the non-IVF patients, and 85.7% (6/7) vs 85.7% (6/7) in the healthy volunteers. The percentage of endometrial Lactobacillus in the healthy volunteers was highly stable within the same menstrual cycle and even in the following cycle. The major taxonomies were Gardnerella, Streptococcus, Atopobium, Bifidobacterium, Sneathia, Prevotella, and Staphylococcus. Fifteen patients achieved pregnancy by a single vitrified-warmed blastocyst transfer during this study; the median percentage of Lactobacillus in the pregnant women was 96.45 ± 33.61%. CONCLUSION: A considerable percentage of non-Lactobacillus-dominated (NLD) microbiota was found in the endometrium of Japanese infertile women. Increasing the endometrial level of the Lactobacilli to >90% might favor the implantation outcome of NLD infertile patients.

Long-term clinical outcomes of testicular sperm extraction and intracytoplasmic sperm injection for infertile men.

Purpose: To find the best methods to achieve the highest pregnancy and birth rates for couples needing testicular sperm extraction (TESE)-intracytoplasmic sperm injection (ICSI). Methods: Retrospectively studied were 801 patients with male factor infertility who had undergone TESE-ICSI between April, 1996 and July, 2016 and who had been categorized into four groups: obstructive azoospermia (OA); non-obstructive azoospermia (NOA); Klinefelter syndrome (KS); and cryptozoospermia (Crypt). The sperm retrieval rate, hormone levels, fertilization rate (FR), pregnancy rate (PR), and birth rate (BR) after ICSI among three groups were compared: fresh testicular sperm (FS)-fresh oocytes (FO) (Group I); frozen-thawed testicular sperm-FO (Group II); and FS-vitrified-warmed oocytes (Group III). Results: The testicular sperm recovery rate was 57.8% (463/801): 89.6% in the Crypt, 97.1% in the OA, 28.9% in the NOA, and 42.2% in the KS groups. The follicle-stimulating hormone levels were significantly higher in the NOA and KS groups and the testosterone levels were significantly lower in the KS group. The FR, PR, and BR were: 65.2%, 43.2%, and 28.5% in group I; 59.2%, 33.4%, and 18.7% in group II; and 56.4%, 33.8%, and 22.1% in group III. Conclusion: Intracytoplasmic sperm injection with FS-FO achieved the best PR and BR. It should be considered what to do in cases with no testicular sperm by TESE. The authors hope that ICSI with donor sperm will be allowed in Japan in the near future.

Efficacy of the endometrial receptivity array for repeated implantation failure in Japan: A retrospective, two-centers study.

Aim: This study aimed to assess the efficacy of the endometrial receptivity array (ERA) as a diagnostic tool and the impact of personalized embryo transfer (pET) for the treatment of patients with recurrent implantation failure (RIF) in Japan. Methods: Fifty patients with a history of RIF with frozen-thawed blastocyst transfers were recruited from July, 2015 to April, 2016. Endometrial sampling for the ERA and histological dating and a pET according to the ERA were performed. The receptive (R) or non-receptive (NR) status of the endometrium as a result of the first ERA, endometrial dating, and pregnancy rates after the pET were analyzed. Results: Of the patients with RIF, 12 (24%) were NR. Among them, eight (66.7%) were prereceptive. A clinical follow-up was possible in 44 patients who underwent the pET. The pregnancy rates were 58.8% per patient and 35.3% per first pET in the R patients and 50.0% per patient and 50.0% per first pET in the NR patients. Discrepancies between the ERA results and histological dating were seen more in the NR patients than in the R patients. Conclusions: For patients with unexplained RIF, there is a significance in searching for their personal window of implantation (WOI) using the ERA, considering the percentage of those who were NR and the pregnancy rates that resulted from the pET. By transferring euploid embryos in a personal WOI, much better pregnancy rates are expected.

Effects of fertility preservation in patients with breast cancer: A retrospective two-centers study.

Purpose: To assess the efficacy of fertility preservation (FP) and the impact of chemotherapy on the reproductive potential of Japanese patients with breast cancer. Methods: Sixty-two patients with breast cancer visited the authors' centers from October, 2003 to June, 2015. They were divided into two groups according to the treatment: oocyte or embryo vitrification for FP before cancer treatment (group A) or infertility treatment after cancer treatment (group B). Group B was divided into two subgroups, B1 (no chemotherapy) and B2 (postchemotherapy), in order to analyze the effect of anticancer drugs on ovarian reserves and assisted reproductive technology outcomes. The number of retrieved oocytes, vitrified oocytes or embryos, and pregnancy rates were analyzed and compared: group A compared to group B1 compared to group B2. Results: The patients in groups A and B1 underwent egg collection without any chemotherapy. The numbers of collected oocytes and vitrified embryos were significantly higher in groups A and B1 than in group B2. Nearly 50% of the in vitro fertilization patients who underwent an embryo transfer (ET) became pregnant, including two patients in group A who underwent a vitrified-warmed ET. Among the pregnant women, 70% did not have chemotherapy. Conclusion: For patients with breast cancer, FP with unfertilized oocytes or embryos before chemotherapy seems to be promising for achieving higher pregnancy rates, with no risk of minimal residual disease.

Residual ethylene glycol and dimethyl sulphoxide concentration in human ovarian tissue during warming/thawing steps following cryopreservation.

There have been 60 births after transplantation of cryopreserved ovarian tissue: 58 using the slow freezing method, and two using the vitrification method. DMSO and EG are widely used as cryoprotectants. However DMSO is a known epimutagen, and EG has been reported to be toxic in high concentrations. In this study, we measured residual DMSO and EG in ovarian tissue after vitrification and slow freezing. Cryoprotectants remained at a high concentration in the vitrified/warmed ovarian tissue just before transplantation (DMSO: 9.8 mg/g, EG: 9.8 mg/g). We must consider the impact of the cryoprotectants on the mother and the baby.

Oxygen consumption rate of early pre-antral follicles from vitrified human ovarian cortical tissue.

The study of human ovarian tissue transplantation and cryopreservation has advanced significantly. Autotransplantation of human pre-antral follicles isolated from cryopreserved cortical tissue is a promising option for the preservation of fertility in young cancer patients. The purpose of the present study was to reveal the effect of vitrification after low-temperature transportation of human pre-antral follicles by using the oxygen consumption rate (OCR). Cortical tissues from 9 ovaries of female-to-male transsexuals were vitrified after transportation (6 or 18 h). The follicles were enzymatically isolated from nonvitrified tissue (group I, 18 h of transportation), vitrified-warmed tissue (group II, 6 and 18 h of transportation) and vitrified-warmed tissue that had been incubated for 24 h (group III, 6 and 18 h of transportation). OCR measurement and the LIVE/DEAD viability assay were performed. Despite the ischemic condition, the isolated pre-antral follicles in group I consumed oxygen, and the mean OCRs increased with developmental stage. Neither the transportation time nor patient age seemed to affect the OCR in this group. Meanwhile, the mean OCR was significantly lower (P < 0.05) in group II but was comparable to that of group I after 24 h of incubation. The integrity of vitrified-warmed primordial and primary follicles was clearly corroborated by the LIVE/DEAD viability assay. These results demonstrate that the OCR can be used to directly estimate the effect of vitrification on the viability of primordial and primary follicles and to select the viable primordial and primary follicles from vitrified-warmed follicles.

Deliveries of babies with normal health derived from oocytes with smooth endoplasmic reticulum clusters.

PURPOSE: To examine the impact on development of derived embryos from smooth endoplasmic reticulum clusters (SERC) in human metaphase II (MII) oocytes. METHODS: Retrospective analysis at Kyono ART Clinic. Comparison of embryological development, pregnancy, live birth and fetal malformation between oocytes with SERC (the SERC(+) group) and those without (the SERC(-) group) in 2,158 patients (3,758 cycles) after ICSI. RESULTS: Fertilization and implantation rate were significantly lower in SERC(+) MII oocytes than in SERC(-) MII oocytes. After the transfer of fresh and vitrified embryos derived from SERC(+) oocytes, 14 pregnancies resulted in 14 healthy babies, including 2 from fresh embryo transfer (ET) and 12 from vitrified-warmed ET, with no malformations. CONCLUSION(S): The presence of SERC in MII oocytes was associated with significantly lower fertilization rates and implantation rates than seen in SERC(-) MII oocytes within SERC (+) cycles. However, SERC had no impact on post-implantation development as well as neonatal outcome.

Evaluation of oxygen consumption in human vitrified and warmed pre-antral follicles after prolonged low temperatures.

PURPOSE: The purpose of this study was to evaluate the effect of transportation at prolonged low temperatures on the survival of pre-antral follicles. METHODS: Ovarian tissue was removed from six women with gender identity disorder. Tissues were stored in an icebox at 4 °C for 6 or 18 h prior to vitrification. After warming, ovarian tissues were cultured for 24 h and follicle survival was assessed via a viability/cytotoxicity kit. Morphological features and oxygen consumption rate (OCR) were evaluated by scanning electrochemical microscopy (SECM). RESULTS: Survival rate of isolated primordial follicles was 95.7 and 100 %, and that of primary follicles was 91.7 and 81.8 % in the 6- and 18-h groups respectively. There was no difference in morphology between the 6- and 18-h storage groups. In comparison with OCR of vitrified-warmed follicles and OCR of 24-h culture after vitrified-warmed follicles, OCR of 24-h culture after vitrified-warmed primordial follicles was significantly higher in both 6-hour (0.02 ± 0.02 vs 0.07 ± 0.04, P < 0.05) and 18-h groups (0.02 ± 0.02 vs 0.11 ± 0.10, P < 0.05). CONCLUSIONS: This strongly suggests that prolonged transportation of ovarian tissue at low temperatures is useful when there are no available local systems for fertility preservation.

The precise timing of embryo splitting for monozygotic dichorionic diamniotic twins: when does embryo splitting for monozygotic dichorionic diamniotic twins occur? Evidence for splitting at the morula/blastocyst stage from studies of in vitro fertilization.

There is a long-held credo, as illustrated in Langman's Medical Embryology (11th ed., Sadler, 2010), that dichorionic diamniotic (DD) twins develop after embryo splitting in the early stages of embryonic development. However, from our clinical experiences of the examination of data from single-embryo transfers in 16 fertility clinics in Japan and from various reports, the majority of occurrences of DD twins have been found in the blastocyst stages.