Lipid droplet biogenesis in the ovary.

Background: Lipid droplets (LDs) are organelles consisting of a central core of neutral lipids covered by a single layer of phospholipids and are found in most eukaryotic cells. Accumulating evidence suggests that LDs not only store neutral lipids but also coordinate with other organelles for lipid metabolism within cells.

Methods: This review focuses on the synthesis of LDs during follicular development and highlights the factors involved in the regulation of LD biogenesis within the ovary.

Assisted reproductive technology in Japan: A summary report for 2022 by the Ethics Committee of the Japan Society of Obstetrics and Gynecology.

Purpose: This descriptive analysis evaluated the 2022 assisted reproductive technology (ART) data collected by the Japan Society of Obstetrics and Gynecology registry.

Methods And Results: In 2022 (cutoff date 30 November 2023), 634 of 635 registered ART facilities participated; 602 implemented ART treatment, with 543 630 registered cycles and 77 206 neonates (9.1% and 10.

Influence of the shortened warming protocol on human blastocyst viability: an in-vitro experimental study.

Research Question: Does the shortened warming protocol impact the cell viability and outgrowth competence of human vitrified blastocysts warmed with or without fatty acids?

Design: In this study, 326 discarded vitrified human blastocysts donated for research by consenting couples were used. The blastocysts were randomly allocated to five groups depending on the warming solutions, protocols and recovery culture media: the control-conventional, control-shortened, FA-conventional, FA-shortened, and FA-shortened/recovery culture with fatty acid (FA-shortened/RF) groups. The blastocysts were warmed with or without fatty acids following the manufacturer's instruction (conventional method) or using the shortened method, in which blastocysts were immersed in a thawing solution for 1 min and then cultured in the recovery medium for 2 h.

Nationwide Survey on the Status of Oncofertility in Japan and Involvement of Embryologists in the Practice of Fertility Preservation.

To investigate the actual status of fertility preservation techniques in oncofertility in Japan and to clarify the involvement of embryologists in this field. This survey was conducted online, targeting embryologists working at 622 facilities registered with the Japan Society of Obstetrics and Gynecology for assisted reproductive technology. The response rate was 56.

Use of time-lapse technology on fertilization verification, embryo evaluation, and utilization: A national survey in Japan.

Background: Time-lapse technology (TLT) has emerged as a significant advancement in the field of assisted reproductive technology (ART), providing continuous observation of embryos. However, limited information exists on the adoption of TLT across ART facilities and the clinical implications of its application in embryo evaluation and fertilization verification. The existing literature has not yet comprehensively examined how TLT data are utilized to optimize ART outcomes, particularly in Japan, where ART practices are highly prevalent.

Developmental perturbation in human embryos: Clinical and biological significance learned from time-lapse images.

Background: Time-lapse technology (TLT) has gained widespread adoption worldwide. In addition to facilitating the undisturbed culture of embryos, TLT offers the unique capability of continuously monitoring embryos to detect spatiotemporal changes. Although these observed phenomena play a role in optimal embryo selection/deselection, the clinical advantages of introducing TLT remain unclear.

Fatty acid supplementation during warming improves pregnancy outcomes after frozen blastocyst transfers: a propensity score-matched study.

This study aimed to examine the viability of human blastocysts after warming with fatty acids (FAs) using an in vitro outgrowth model and to assess pregnancy outcomes after a single vitrified-warmed blastocyst transfer (SVBT). For the experimental study, we used 446 discarded vitrified human blastocysts donated for research purposes by consenting couples. The blastocysts were warmed using FA-supplemented (FA group) or non-FA-supplemented (control group) solutions.

Assisted reproductive technology in Japan: A summary report for 2021 by the Ethics Committee of the Japan Society of Obstetrics and Gynecology.

Purpose: The Japan Society of Obstetrics and Gynecology (JSOG) registry gathers comprehensive data from registered assisted reproductive technology (ART) facilities in Japan. Herein, we report 2021 ART cycle characteristics and outcomes.

Methods: Descriptive statistics were used to summarize and analyze 2021 data.

Improved pregnancy prediction performance in an updated deep-learning embryo selection model: a retrospective independent validation study.

Research Question: What is the effect of increasing training data on the performance of ongoing pregnancy prediction after single vitrified-warmed blastocyst transfer (SVBT) in a deep-learning model?

Design: A total of 3960 SVBT cycles were retrospectively analysed. Embryos were stratified according to the Society for Assisted Reproductive Technology age groups. Embryos were scored by deep-learning models iDAScore v1.

Preimplantation genetic testing using comprehensive genomic copy number analysis is beneficial for balanced translocation carriers.

Balanced chromosomal translocation is one of chromosomal variations. Carriers of balanced chromosomal translocations have an increased risk of spontaneous miscarriage. To avoid the risk, preimplantation genetic testing (PGT) using comprehensive genomic copy number analysis has been developed.

Comparing performance between clinics of an embryo evaluation algorithm based on time-lapse images and machine learning.

Purpose: This article aims to assess how differences in maternal age distributions between IVF clinics affect the performance of an artificial intelligence model for embryo viability prediction and proposes a method to account for such differences.

Methods: Using retrospectively collected data from 4805 fresh and frozen single blastocyst transfers of embryos incubated for 5 to 6 days, the discriminative performance was assessed based on fetal heartbeat outcomes. The data was collected from 4 clinics, and the discrimination was measured in terms of the area under ROC curves (AUC) for each clinic.

The destinies of human embryos reaching blastocyst stage between Day 4 and Day 7 diverge as early as fertilization.

Study Question: What clinical and laboratory differences emerge from parallel direct comparison of embryos reaching the blastocyst stage between Days 4, 5, 6, and 7 (Days 4-7)?

Summary Answer: Increasing times to blastocyst formation are associated with a worse clinical outcome and perturbations in developmental patterns appear as early as the fertilization stage.

What Is Known Already: Previous evidence indicates that later times to blastocyst development are associated with a worse clinical outcome. However, the vast majority of these data concern Day 5 and Day 6 blastocysts, while Day 4 and Day 7 blastocysts remain less thoroughly investigated.

Fatty acid supplementation into warming solutions improves pregnancy outcomes after single vitrified-warmed cleavage stage embryo transfers.

Purpose: This study aimed to examine the embryonic development of human 4-cell stage embryos after warming with fatty acids (FAs) and to assess the pregnancy outcomes after single vitrified-warmed cleavage stage embryo transfers (SVCTs).

Methods: Experimental study: A total of 217 discarded, vitrified human 4-cell stage embryos donated for research by consenting couples were used. The embryos were warmed using the fatty acid (FA)-supplemented solutions (FA group) or nonsupplemented solutions (control group).

Association between endometrial thickness before ovulation, live birth, and placenta previa rates in clomiphene citrate-treated cycles.

Background: Although a recent study reported that the pregnancy outcomes in the first trimester were more correlated with endometrial thickness on the day of the trigger than with endometrial thickness on the day of single fresh-cleaved embryo transfer, it remains unclear whether endometrial thickness on the day of the trigger can predict live birth rate after a single fresh-cleaved embryo transfer.

Objective: This study aimed to examine whether endometrial thickness on the trigger day is associated with live birth rates and whether modifying the single fresh-cleaved embryo transfer criteria to reflect endometrial thickness on the trigger day improved the live birth rate and reduced maternal complications in a clomiphene citrate-based minimal stimulation cycle.

Study Design: This was a retrospective study of the outcomes of 4440 treatment cycles of women who underwent single fresh-cleaved embryo transfer on day 2 of the retrieval cycle.

Post-warming culture of human vitrified blastocysts with prolactin improves trophoblast outgrowth.

Background: Human embryos express the prolactin (PRL) receptor at the morula and blastocyst stages. Treatment with PRL from cleavage to the blastocyst stage improves blastocyst outgrowth on fibronectin-coated dishes. However, whether post-warming PRL treatment of blastocysts cultured without PRL could improve outgrowth competence remains unknown.

Assisted reproductive technology in Japan: A summary report for 2020 by the ethics Committee of the Japan Society of obstetrics and gynecology.

Purpose: Since 1986, the Japan Society of Obstetrics and Gynecology assisted reproductive technology (ART) registry system has collected data on national ART use and outcomes trends in Japan. Herein, we describe the characteristics and outcomes of ART cycles registered during 2020 and compare the results with those from 2019.

Methods And Results: In 2020, 621 ART facilities participated in the registration.

Does embryo categorization by existing artificial intelligence, morphokinetic or morphological embryo selection models correlate with blastocyst euploidy rates?

Research Question: Does embryo categorization by existing artificial intelligence (AI), morphokinetic or morphological embryo selection models correlate with blastocyst euploidy?

Design: A total of 834 patients (mean maternal age 40.5 ± 3.4 years) who underwent preimplantation genetic testing for aneuploidies (PGT-A) on a total of 3573 tested blastocysts were included in this retrospective study.

Endometrial preparation and maternal and obstetrical outcomes after frozen blastocyst transfer.

Background: Two types of endometrial preparation protocols are used for frozen embryo transfers in current practice: hormone replacement and the natural cycle. Endometrial preparation in the natural cycle reportedly increases the chances of live birth and decreases early pregnancy loss compared with that in the hormone replacement cycle. However, the influence of endometrial preparation on maternal and neonatal health remains unclear.