Assisted reproductive technologies (ARTs) are performed worldwide in the equine industry to produce genetically valuable foals. Among them, ovum pick up (OPU) combined with intra-cytoplasmic sperm injection (ICSI) can now be more efficient than embryo transfer (ET) under optimal conditions. However, OPU is not a benign procedure for the mare and the process is costly. Improved efficiency is therefore in the interest of everyone, maximizing mare welfare and optimizing economics for the client. One of the key factors of success is the antral follicle count (AFC) at the time of OPU and subsequently the number of oocytes obtained. Variations in AFC are reported between individuals and between geographical areas. This leads to a significant increase in numbers of embryos produced per session in some countries compared to others, independent of the laboratory efficiency. This article revisits the basics of folliculogenesis involved in establishment of the antral follicle population and explores work in other species given the paucity of equine research in this area. The aim of the review is to elucidate interesting areas of further research that could generate essential information for clinicians and clients about the management and selection of the donor mare for OPU and potentially identify pharmacological targets for manipulation.

UNASSIGNED: This study compared, in high responders undergoing IVF treatment, GnRH agonist-only trigger and dual trigger on oocyte retrieval rate and cumulative live birth rate (LBR). The aim was to determine if the GnRH agonist-only triggers had provided outcomes comparable to dual trigger, while minimizing the risk of ovarian hyperstimulation syndrome (OHSS).
UNASSIGNED: A retrospective, matched case-control study was conducted at Taichung Veterans General Hospital, Taiwan, including women who underwent IVF/ICSI between January 1, 2014, and December 31, 2022. Inclusion criteria were: GnRH antagonist protocol and estrogen level >3,000 pg/ml on trigger day. Exclusion criteria were: immune/metabolic diseases, donated oocytes, and mixed stimulation cycles. Propensity score matching was applied to balance age, AMH level, and oocyte number between the GnRH agonist-only and dual trigger groups. Outcomes were analyzed for patients who had complete treatment cycles, focusing on oocyte retrieval rate and cumulative LBR.
UNASSIGNED: We analyzed 116 cycles in the agonist-only group, and 232 cycles in the dual trigger group. No inter-group difference was found in their age, BMI, and AMH levels. The dual trigger group had a higher oocyte retrieval rate (93% vs. 80%; p <0.05), while fertilization rates, blastocyst formation rates, and cumulative LBR were comparable. Notably, no OHSS cases had been reported in the GnRH agonist-only group, compared with 7 cases in the dual trigger group.
UNASSIGNED: GnRH agonist-only triggers resulted in a lower oocyte retrieval rate compared to dual triggers but did not significantly affect cumulative LBR in high responders. This approach effectively reduces OHSS risk without compromising pregnancy outcomes, making it a preferable option in freeze-all strategies, despite a longer oocyte pick-up duration and a medium cost. GnRH agonist-only trigger, however, may not be suitable for fresh embryo transfers or patients with low serum LH levels on trigger day.

This study was aimed to investigate the impact of intracytoplasmic sperm injection (ICSI) on reproductive outcomes in couples with non-male factor infertility and frozen-thawed embryo transfer (FET) treatment. This retrospective cohort study involved a total of 10,143 cycles from 6206 couples who underwent FET at the Third Affiliated Hospital of Zhengzhou University between January 2016 and September 2022. Patients were categorized into two groups based on the insemination methods of transferred embryos. Clinical and neonatal outcomes were compared between ICSI and conventional in vitro fertilization (cIVF) groups. The results showed that ICSI was not associated with improved clinical outcomes compared to cIVF. However, ICSI was associated with lower birthweight when twins were born. In conclusion, although subgroup analysis showed that ICSI was associated with slightly improved live birth rate for infertile couples with non-male factor infertility compared to cIVF, the regression analysis showed that ICSI did not demonstrate any improvement of the reproductive outcomes. The infertile women with twin pregnancies should be further informed of the lower birthweight and lower birth length when their oocytes were inseminated with ICSI. The findings of this study provide valuable insights for clinicians when discussing the benefits and risks of ICSI in patients with non-male factor infertility.

OBJECTIVE: This study aimed to examine the correlation between different dominant follicle proportions (DFPs) and outcomes of in-vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) among patients classified under POSEIDON Groups 3 and 4, who underwent gonadotropin-releasing hormone antagonist (GnRH-ant) protocols. Additionally, it sought to determine the optimal DFP threshold for trigger timing.
METHODS: A retrospective analysis was performed on patients classified under POSEIDON Groups 3 (n = 593) and 4 (n = 563) who underwent GnRH-ant protocols for controlled ovarian hyperstimulation (COH) between 2016 and 2022. These patients were categorized into two groups based on their DFPs, defined as the ratio of ≥ 18-mm dominant follicles to ≥ 12-mm follicles on the trigger day (DFP ≤ 40% and DFP ≥ 40%). Statistical analyses, including restricted cubic spline (RCS) and multivariate logistic regression, were employed to assess the relationship between DFP and IVF/ICSI outcomes.
RESULTS: Demographic characteristics of patients were similar across groups. In POSEIDON Groups 3 and 4, DFP > 40 was associated with a significant decrease in the number (No.) of oocytes retrieved, cleaved embryos, and available embryos. Moreover, following the GnRH-ant cycle, the clinical pregnancy and live birth rates in fresh embryo transfer (ET) were notably reduced in the DFP > 40 group compared with the DFP ≤ 40 group, whereas no significant differences were observed in the pregnancy outcomes of the first frozen-thawed embryo transfer (FET) between the groups. In POSEIDON Group 3, the cumulative clinical pregnancy rate (CCPR) and cumulative live birth rate (CLRB) were significantly higher in the DFP ≤ 40 subgroup than in the DFP > 40 subgroup, with a notable decrease in CLRB observed with increasing DFP levels. However, in POSEIDON Group 4, no significant differences in CCPR and CLRB were found between the groups. Logistic regression analysis identified age and the No. of oocytes retrieved as pivotal factors influencing CLRB in Group 4.
CONCLUSIONS: For patients in POSEIDON Group 3, maintaining a DFP ≤ 40 mm is crucial to achieve optimal laboratory and pregnancy outcomes by avoiding delayed triggering. However, for patients in POSEIDON Group 4, age remains a critical factor influencing CLRB regardless of DFP, although a higher No. of oocytes retrieved and available embryos with DFP ≤ 40 is beneficial.

OBJECTIVE: To investigate the etiology, diagnosis and treatment of 45,X/46,XY mixed gonadal dysgenesis and the patients\' clinical characteristics of conception, pregnancy and delivery, with purpose of improving the treatment and pregnancy management of the patients.
METHODS: We retrospectively analyzed the clinical data on a pregnant patient with 45,X/46,XY mixed gonadal dysgenesis.
RESULTS: Based on the findings of hypoplasia of secondary sexual characteristics, streak gonads, chromosome karyotype incompatibility with social sex, and chromosome aberration in the gonadal tissue, the patient was diagnosed with 45,X/46,XY mixed gonadal dysgenesis, received oocyte donation and intracytoplasmic sperm injection-embryo transfer (ICSI-ET), and achieved a live birth.
CONCLUSIONS: Female patients with 45,X/46,XY mixed gonadal dysgenesis are infertile, but can achieve pregnancy through oocyte donation. However, the incidence rates of pregnancy complications and abnormal delivery are higher in these patients than in normal females. The perinatal outcomes can be improved by efficient treatment and pregnancy management of the patients.

OBJECTIVE: To investigate the effect of the early blastocyst on pregnancy and birth outcomes in patients in vitro fertilization/(early rescue) intracytoplasmic sperm injection-embryo transfer [IVF/(early rescue)ICSI-ET] cycles.
METHODS: In this retrospective cohort study, 289 patients with single-blastocyst transfer within IVF/(early rescue)ICSI-ET treatment cycle were included and divided into the early (n = 48, Gardner stage = 1 or 2) and the fully expanded blastocyst (n = 241, Gardner stage ≥ 3) groups. The differences in pregnancy and birth outcomes between the two groups were compared.
RESULTS: There was no significant differences between the two groups in baseline indicators, including demographic characteristics and clinical treatment (P> 0.05).The clinical outcomes indicators in the early and the fully expanded blastocyst groups were compared, including the number of transferable embryos on the third day (D3)5.0 (4.0, 6.8) vs. 6.0 (5.0, 8.0) (P = 0.001), the number of remaining embryos frozen per cycle 1.0 (0.3, 2.0) vs. 3.0 (2.0, 5.0) (P<0.001); the number of cycles of unfrozen embryos 13/48 (27.1%) vs. 12/241 (5.0%) (P<0.001); the pregnancy outcome including the clinical pregnancy rate (CPR) 20/48 (41.7%) vs. 129/241 (53.5%) (P>0.05); the live birth rate (LBR)15/48 (31.3%) vs.106/241 (44.0%) (P>0.05). There were no significant differences in birth outcomes, such as gestational week of labor, mode of delivery, neonatal birth weight, height, Apgar score, sex ratio, and birth defects between the two groups (P>0.05).Multivariate binary logistic regression showed the same result, i.e., early blastocyst transfer in fresh cycle was not a risk factor for clinical pregnancy (OR = 0.516, 95% CI = 0.260-1.022) and live birth (OR = 0.521, 95% CI = 0.252-1.079).
CONCLUSIONS: Compared with the fully expanded blastocyst group, the CPR and LBR in the early blastocyst group of the fresh transfer cycles were relatively ideal, and there were no significant differences in birth outcomes and neonatal status between the two groups.

Background and Objectives: Although considerable research has been devoted to examining the distinctions between fresh and frozen embryo transfer regarding obstetric outcomes and rates of pregnancy success, there is still a scarcity of thorough analyses that specifically examine neonatal outcomes. The objective of our study was to provide an in-depth analysis of neonatal outcomes that occur after the transfer of fresh and frozen embryos (ET vs. FET) in IVF/ICSI cycles. Materials and Methods: Multiple databases (PubMed/MEDLINE, Cochrane Library, Web of Science, Wiley, Scopus, Ovid and Science Direct) were searched from January 1980 to February 2024. Two reviewers conducted the article identification and data extraction, meeting inclusion and exclusion criteria. The methodological quality was evaluated using the Newcastle-Ottawa Scale (NOS) or the revised Cochrane Risk of Bias Tool. The meta-analysis was performed using RevMan 5.4. Results: Twenty studies, including 171,481 participants in total, were subjected to qualitative and quantitative analyses. A significant increase in preterm birth rates was noted with fresh embryo transfer compared to FET in the overall IVF/ICSI population (OR 1.26, 95% CI 1.18-1.35, p < 0.00001), as well as greater odds of a low birth weight (OR 1.37, 95% CI 1.27-1.48, p < 0.00001) and small-for-gestational-age infants in this group (OR 1.81, 95% CI 1.63-2.00, p < 0.00001). In contrast, frozen embryo transfer can result in macrosomic (OR 0.59, 95% CI 0.54-0.65, p < 0.00001) or large-for-gestational-age infants (OR 0.64, 95% CI 0.60-0.69, p < 0.00001). No significant difference was observed regarding congenital malformations or neonatal death rates. Conclusions: This systematic review confirmed that singleton babies conceived by frozen embryo transfer are at lower risk of preterm delivery, low birthweight and being small for gestational age than their counterparts conceived by fresh embryo transfer. The data support embryo cryopreservation but suggest that elective freezing should be limited to cases with a proven indication or within the framework of a clinical study.

Background and Objectives: Fertilized zygotes normally display two pronuclei (PN), but abnormal fertilization patterns (0, 1 or >2PN) are observed daily in IVF labs. Multiple PN zygotes (>2) are generally discarded due to an increased risk of aneuploidy. However, the decision to transfer or not transfer 1PN-derived embryos remains controversial. The aims of our study were to analyze the neonatal outcomes of fresh or frozen-thawed embryos derived from 1PN zygotes, and to evaluate the influence of the fertilization method. Materials and Methods: Data were retrospectively collected from cycles performed between January 2018 and December 2022. Fresh cycles were analyzed for the comparative fate of 1PN zygotes (n = 1234) following conventional in vitro fertilization (cIVF; n = 648) or intracytoplasmic sperm injection (ICSI; n = 586), as well as the results of the 64 transfers of 1PN-derived embryos (pregnancy rate (PR) and neonatal outcomes). This pregnancy follow-up was also applied to 167 transfers of frozen-thawed 1PN-derived embryos. Results: In fresh cycles, 46% of the 1PN zygotes in the cIVF group developed into embryos of sufficient quality to be transferred or frozen (day 3 or 5/6). This rate was lower in the fresh ICSI cycles (33%). Blastulation rate was also significantly higher in the cIVF group (44%) in comparison to the ICSI group (20%). The fresh single embryo transfers (32 per group) allowed seven pregnancies in the cIVF group (PR = 21.9%) as compared to four pregnancies in the ICSI group (PR = 12.5%). In the cIVF group, five deliveries of healthy newborns were achieved, but only one in the ICSI group. In frozen/thawed cycles, 36 pregnancies were obtained out of the 167 transfers. A non-significant difference was observed between embryos derived from cIVF cycles (PR = 26%) and ICSI cycles (PR = 16%) with 18 and 8 healthy babies born, respectively. Conclusions: We observed better outcomes for 1PN zygotes in cIVF cycles in comparison to ICSI cycles. Our center policy to transfer good-quality 1PN-derived embryos allowed the birth of 32 healthy babies.

Necrozoospermia is a special type of asthenospermia, in which mass sperm death is commonly seen, with an incidence rate of 0.2%－0.4%. Studies on necrospermia are rarely reported. Its etiology is complicated, and its diagnosis and treatment are very difficult. This article focuses on the main etiological factors, pathophysiological mechanism, diagnostic methods and treatment strategies of necrospermia, aiming to provide some reference for andrologists and reproduction physicians, as well as a theoretical guidance for intracytoplasmic sperm injection (ICSI) in the treatment of the patients with necrospermia.

OBJECTIVE: The aim of this study was to compare the obstetric and perinatal complications in women who became pregnant with autologous oocytes and those who received donated oocytes (DO) in intracytoplasmic sperm injection cycles (ICSI).
METHODS: A retrospective cohort study was carried out by collecting data from medical records between 2019 and 2022. Only patients who underwent ICSI in an induced cycle using their own or freshly DO, with male infertility factor and tubal factor, were included.
RESULTS: A total of 120 patients were assessed, comprising 51 cases utilizing their own oocytes (control group) and 69 cases employing DO (study group). Patients receiving DO (n=69) exhibited a significantly higher mean age compared to those utilizing their own oocytes (n=51) (41.96±2.16 vs 38.54±1.42 years, p<0.001). There was no significant association between the source of oocytes and gestational age at delivery (p=0.296), birth weight (p=0.836), admission to neonatal intensive care unit (ICU) (p=0.120), or maternal admission to adult ICU (p=0.767). Additionally, the origin of oocytes did not demonstrate any significant association with the risk of pre-eclampsia (p=0.357), gestational diabetes mellitus (p=0.187), premature rupture of membranes (p=0.996), uterine atony (p=0.996), placenta previa (p=0.393), oligohydramnios (p=0.393), or gestational hypertension (p=0.393).\"
CONCLUSIONS: An increase in obstetric and perinatal complications was not observed in pregnancies with DO compared to pregnancies with autologous oocytes in women undergoing ICSI without prior comorbidities. Further studies with larger sample sizes are required to validate our findings.