Fertilization and neonatal outcomes after early rescue intracytoplasmic sperm injection: a retrospective analysis of 16,769 patients

Correlation analysis of a novel artificial intelligence optical microscope-assisted semen assessment system with IVF outcomes

PURPOSE

On the day of fresh oocyte retrieval in in vitro fertilization (IVF) cycles, a novel portable artificial intelligence optical microscope (AIOM) was employed to assist in the assessment of semen parameters. This study analyzed the correlation between sperm kinetic and morphological parameters with short-term IVF outcomes. Additionally, it explored whether these parameters could serve as predictive indicators for rescue intracytoplasmic sperm injection (R-ICSI) in IVF patients.

METHODS

A retrospective analysis was conducted on patients undergoing short-term IVF at the West China Second Hospital of Sichuan University between May 2021 and May 2024. Based on fertilization outcomes, the short-term IVF patients were categorized into a successful fertilization group (group A, n = 281) and a group requiring R-ICSI after failed fertilization (group B, n = 49). AIOM was utilized to analyze semen parameters including pH, sperm concentration, sperm motility parameters, sperm movement trajectory parameters, and sperm morphological parameters. The study further investigated the correlation between these short-term IVF fertilization-related laboratory indicators and IVF outcomes.

RESULTS

No statistically significant difference was observed in semen pH between the two groups. However, there were significant differences in sperm concentration and the majority of motility parameters. Specifically, compared to group A, patients in group B exhibited lower sperm concentration (p = 0.01), motility (p = 0.01), local motility (p = 0.01), progressive motility (PR) (p = 0.00), total motility (p = 0.01), and amplitude of lateral head displacement (ALH) (p < 0.01), along with higher immotility (p = 0.00). No statistically significant differences were found between the two groups in other sperm motility, velocity, or trajectory parameters. Additionally, sperm morphological parameters were also associated with short-term IVF fertilization outcomes. Compared to group A, group B had higher sperm head length mean (p < 0.01), head perimeter mean (p < 0.01), and head area mean (p = 0.01), as well as lower tail length mean (p = 0.01). Multivariate regression analysis of fertilization outcomes indicated that higher immotility (p = 0.01) and head length mean (p < 0.01), along with lower tail length mean (p = 0.04), were independent risk factors affecting successful short-term IVF fertilization. Notably, head length mean showed a significant negative correlation with polyspermy rate (p < 0.01), whereas tail length mean was significantly positively correlated with polyspermy rate (p < 0.01).

CONCLUSION

Optimization of semen parameters with AIOM at the time of fertilization is significantly associated with short-term IVF fertilization outcomes. Abnormal semen parameters at fertilization-specifically, higher immotility and head length mean, along with lower tail length mean-can be considered risk factors for fertilization failure and may serve as predictive indicators for potential R-ICSI.

Spindle observation aids decision-making for early rescue ICSI

OBJECTIVE

To investigate whether spindle visualization using polarized light microscopy (PLM) can assist in identifying unfertilized oocytes prior to early rescue intracytoplasmic sperm injection (R-ICSI).

METHODS

This retrospective cohort study included 356 early R-ICSI cycles, of which 24 were excluded from the analysis. The remaining 332 cycles were divided into study group and control group based on whether spindle observation had been performed before early R-ICSI. The fertilization rate, embryo development, and clinical outcome were compared between the two groups.

RESULTS

Of the 356 participants included, 332 completed follow-up analysis. The study group demonstrated a significantly higher normal fertilization rate (82.55% vs. 71.49%, P < 0.01) and a lower 3PN rate (3.17% vs. 8.89%, P < 0.01) after following R-ICSI. For oocytes without visible spindles in the study group or those with fragmented polar bodies in the control group, in vitro fertilization (IVF) was performed, resulting in a higher normal fertilization rate in the study group (53.37% vs. 36.43%, P < 0.01). However, there was no significant difference between the two groups in terms of embryo development and implantation potential. In the high-age subgroup (over 35 years old), the normal cleavage rate was significantly higher in the spindle examination group compared to the non-observation group (38.60% vs. 22.47%, P < 0.05).

CONCLUSION

Utilizing PLM for spindle observation can effectively identify oocytes suitable for early R-ICSI to improve fertilization outcomes and optimize embryo development in women over 35 years old.

Congenital anomalies observed in children conceived through assisted reproductive technology-a systematic review and meta-analysis

Congenital anomalies (CAs) are a leading cause of perinatal and child mortality. With the increasing use of assisted reproductive technology (ART), there is a growing need for research on the health outcomes of children conceived through ART. This systematic review was performed to assess the incidence of CAs in ART-conceived children compared to those conceived naturally. This review followed the PRISMA 2020 guidelines and was registered with PROSPERO. A total of 113 studies were included in this meta-analysis, comprising 768,929 children in the ART group and 40,709,337 children in the control group which comprised spontaneously conceived (SC) children. The primary findings indicated that ART-conceived children have a marginally higher risk of CAs compared to the control group. Subgroup analyses showed that children conceived via ICSI, Day 3 transfer, and fresh embryo transfer (ET) had a slightly higher risk of CAs than those conceived via IVF, Day 5 transfer, or frozen embryo transfer (FET). The study highlights a slightly increased incidence of CAs among ART-conceived children over SC children, underscoring the importance of improving ART methods and closely monitoring the health of these children to reduce the risk of CAs.

Rescue intracytoplasmic sperm injection improved cumulative live birth rate for cycles with second polar body extrusion rate <50% in young women: generalized addictive model

OBJECTIVE

To determine the indications for early rescue intracytoplasmic sperm injection (ICSI) application.

DESIGN

A retrospective cohort study.

SUBJECTS

The study included 19,808 patients who underwent conventional in vitro fertilization (IVF) or rescue ICSI for their first cycles between February 2017 and December 2021.

EXPOSURE

Rescue ICSI cycles constituted the study group, where oocytes that had not extruded the second polar body 4-6 hours after insemination were rescued by ICSI. The control group consisted of conventional IVF cycles with no interventions to rescue oocytes without the second polar body. Generalized additive models were constructed to describe the relationship between the second polar body extrusion rate and cumulative live birth rate in conventional IVF and rescue ICSI cycles, respectively. The cutoff value of the second polar body extrusion rate guiding rescue ICSI application was determined from the intersection point of generalized additive models. Maternal age range applicable to rescue ICSI was further analyzed using the same method. Clinical outcomes were compared between conventional IVF and rescue ICSI cycles across different second polar body extrusion rate and maternal age subgroups.

MAIN OUTCOME MEASURES

The second polar body extrusion rate and maternal age range for rescue ICSI application, normal fertilization rate, and cumulative live birth rate.

RESULTS

Generalized additive models showed that the cutoff value for the second polar body extrusion rate about rescue ICSI application was 50%. When the rate <50%, normal fertilization rate and cumulative live birth rate (63.7% vs. 46.1%; odds ratio, 1.609; 95% confidence interval, 1.276-2.030) were significantly higher in rescue ICSI cycles than conventional IVF cycles. When the rate ≥50%, rescue ICSI cycles had similar normal fertilization rate and cumulative live birth rate compared with conventional IVF cycles. Further analysis on maternal age in cycles with second polar body extrusion rate <50% released that rescue ICSI cycles showed a higher cumulative live birth rate (67.7% vs. 48.3%; odds ratio, 1.732; 95% confidence interval, 1.361-2.202) than conventional IVF cycles for women aged <38 years.

CONCLUSION

In vitro fertilization cycles with second polar body extrusion rate <50% in women aged <38 years was applicable to early rescue ICSI.

The clinical value of short-term insemination: a retrospective analysis of 3496 patients

BACKGROUND

The safety and effectiveness of short-term insemination remain a subject of controversy. This study aims to investigate the impact of short-term insemination on both embryo quality and pregnancy outcomes and whether it is necessary to apply short-term insemination to all patients underwent in vitro fertilization (IVF).

METHODS

A retrospective analysis was conducted on 3,496 patients from two centers over the period January 2016 to December 2022. Of these, 1307 patients underwent IVF, 1656 patients were treated with short-term IVF, 166 patients received early rescue intracytoplasmic sperm injection (R-ICSI) and 367 patients were treated with ICSI. The clinical and neonatal outcomes were compared between the two groups.

RESULTS

The rate of high-quality embryos was significantly lower in the short-term IVF group compared to the routine IVF group (59.89% vs. 68.16%) (P = 0.000), the rate of blastocyst formation was significantly lower in the short-term IVF group compared to the routine IVF group (44.99% vs. 61.34%) (P = 0.000). There were no significant differences in clinical outcomes or neonatal outcomes between the two groups, irrespective of whether fresh or frozen embryos were used (both P > 0.05). The incidence of ≥ 3PN demonstrated no significant difference between the early R-ICSI and ICSI groups (1.04% vs. 0.66%) (P = 0.114), furthermore, the clinical outcomes were similar in both groups, for both fresh and frozen embryos (both P > 0.05).

CONCLUSIONS

For patients with primary fertility, short-term IVF combined with early R-ICSI can effectively prevent potential low fertilization or fertilization failure, reduce the risk of patients with no transferable embryo, avoid the waste of resources and had no adverse effects on neonatal outcomes. However, short-term IVF reduced the oocytes utilization rate in one single oocyte pick-up cycle, for patients with no risk factors for fertilization failure, the overnight fertilization is still one of the most important ways of insemination worthy of affirmation.

TRIAL REGISTRATION

NA.

A machine learning model for predicting fertilization following short-term insemination using embryo images

Purpose

This study established a machine learning model (MLM) trained on embryo images to predict fertilization following short-term insemination for early rescue ICSI and compared its predictive performance with the embryologist's manual classification.

Methods

Embryo images at 4.5 and 8 h post-insemination were preprocessed into vectors using ResNet50. The Light Gradient Boosting Machine (Light GBM) was employed for training vectors. Fertilization in the test dataset was assessed by MLM, with seven senior and 11 junior embryologists. Predictive metrics were analyzed using repeated measures ANOVA and paired t-tests.

Results

Comparing MLM, senior embryologists, and junior embryologists, significant differences were observed in accuracy (0.71 ± 0.01, 0.75 ± 0.05, 0.61 ± 0.05), recall (0.84 ± 0.02, 0.84 ± 0.10, 0.61 ± 0.07), F1-score (0.78 ± 0.01, 0.81 ± 0.04, 0.66 ± 0.04), and area under the curve (0.73 ± 0.0 3, 0.73 ± 0.06, 0.61 ± 0.07), the MLM outperforming junior embryologists with <1 year of experience. No significant differences were observed between the MLM and senior embryologists with over 5 years of experience.

Conclusions

MLM can effectively predict fertilization following short-term insemination by analyzing cytoplasmic changes in images. These results underscore the potential to enhance clinical decision-making and improve patient outcomes.

Human oocyte zona pellucida abnormalities: evaluation of clinical impact for different zona pellucida abnormalities and role of using assisted hatching

BACKGROUND

Zona pellucida (ZP) plays an important role in oocyte development and fertilisation, as well as in early embryo development. However, there is currently no exploration of systematic categorising and clinical treatment measures for patients with abnormal ZP, especially the fast and easy method that can be used clinically.

METHODS

In this study, 185 patients with abnormal ZP (ZPA) and 222 patients with normal ZP (ZPN) were enrolled and analysed.

RESULTS

Patients with ZPA exhibited altered hormone levels and lower laboratory outcomes in in vitro fertilisation (IVF), such as reduced MII rate, cleavage rate, high-quality embryo rate, and blastocyst formation rate compared to ZPN group. ZPA patients were sub-categorised into ZPA-A/B/C/D group according to the status of oocyte polar body and the width of perivitelline space (PVS). There are also differences in the degree of sperm binding to ZP derived from different ZPA patients and the elasticity of the oocyte membrane. ZPA subgroup analysis revealed further disparities in various IVF parameters and pregnancy outcomes. In addition, by performing different treatments on oocytes derived from ZPA patients, we found that ZP assisted hatching before the first oocyte cleavage on D1 of embryonic development in the ZPA-A/B groups and before blastocyst expansion on D4 of embryonic development in the ZPA-C/D groups were beneficial to improve embryonic development.

CONCLUSION

The degree of the impact on clinical outcomes is correlated with the types of ZPA, and laser-assisted hatching of the ZP helps to improve embryonic development in patients with ZPA.

Indications affect neonatal outcomes following early rescue ICSI: a retrospective study

PURPOSE

To investigate the impact of heterogeneity in patient indications or insemination protocols on neonatal outcomes of singletons following early rescue ICSI (rICSI) treatments.

METHODS

A retrospective study was conducted. Propensity score matching and multivariable logistic regression were used to adjust for confounders and biases.

RESULTS

A total of 9095 IVF patients, 2063 ICSI patients, and 642 early rICSI patients were included in the study. No differences were detected in neonatal outcomes except small for gestational age (SGA) which increased in early rICSI patients compared with both unmatched and matched IVF groups with the risk ratio (RR) of 1.31 (95% CI: 1.05, 1.64) and 1.49 (95% CI: 1.05, 2.12). Further analysis showed that SGA increased significantly in partial fertilization failure (PFF) cycles with RRs of 1.56 (95% CI: 1.08, 2.27) and 1.78 (95% CI: 1.22, 2.59) compared with both unmatched and matched IVF patients but not in TFF patients. A positive association between fertilization rate via IVF and birth weight z-score was revealed in the PFF patients.

CONCLUSION

Early rICSI in patients with total fertilization failure (TFF) appeared to be safe in terms of neonatal outcomes. However, when expanding the indications of rICSI to PFF patients, the SGA in the offspring increased, suggesting a potential effect on long-term health. Since other treatment options, such as using only the IVF-origin embryos still exist for these patients, further studies were needed to confirm the optimal decision for these patients.

Cumulative live birth rate and neonatal outcomes after early rescue ICSI: a propensity score matching analysis

STUDY QUESTION

Is early rescue ICSI (E-RICSI) an effective and safe technique compared to conventional ICSI?

SUMMARY ANSWER

Despite the higher multi-pronucleus (PN) rate compared to conventional ICSI, E-RICSI did not add extra risks to clinical and neonatal outcomes.

WHAT IS KNOWN ALREADY

Based on the finding that the second polar body was released in 80% of fertilized oocytes by 4 h after exposure to spermatozoa and in ∼90% of fertilized oocytes by 6 h, E-RICSI brings forward the timing of rescue ICSI to 6 h after initial insemination, and effectively prevents oocyte aging and embryo-uterus asynchrony. However, some researchers still voice concerns about the efficacy and safety of E-RICSI, and comparative studies are limited.

STUDY DESIGN SIZE DURATION

A retrospective cohort study was conducted on patients who underwent conventional ICSI or E-RICSI treatment between January 2015 and December 2020 at a university-affiliated hospital. Using 1:1 propensity score matching, 1496 cases entered each group.

PARTICIPANTS/MATERIALS SETTING METHODS

In total, 1496 couples undergoing conventional ICSI oocyte retrieval cycles and 1496 undergoing E-RICSI oocyte retrieval cycles were enrolled in this study, and basic clinical characteristics, embryologic data, clinical outcomes and neonatal data were compared between groups. The embryos in the E-RICSI group were divided into two subgroups: those fertilized by iIVF (IVF subgroup) and those fertilized by E-RICSI (E-RICSI subgroup); the embryologic data, clinical outcomes, and neonatal data for these subgroups were also compared with the conventional ICSI group. Logistic regression was used for statistical analysis with potential confounder adjustment.

MAIN RESULTS AND THE ROLE OF CHANCE

The 2PN rate, blastocyst formation rate, and viable blastocyst formation rate of the E-RICSI group were significantly lower compared to the conventional ICSI group (2PN rate: P < 0.001; blastocyst formation rate: P < 0.001; viable blastocyst formation rate: P = 0.004), and the multi-PN rate in the E-RICSI group was significantly higher than the conventional ICSI group (P < 0.001). However, the number of 2PN embryos, normal cleavage embryo rate, Day 3 high-quality cleavage embryo rate, and high-quality blastocyst rate were similar between groups. When considering the IVF embryos and E-RCSI embryos in the E-RICSI group independently, the 2PN rate of the conventional ICSI group was significantly lower than E-RICSI subgroup but higher than the IVF subgroup, whereas the blastocyst formation rate and viable blastocyst formation rate were higher than E-RICSI embryos but comparable to IVF embryos. As for the clinical and neonatal outcomes, the implantation rate of the E-RICSI subgroup was significantly lower than the IVF subgroup but comparable to the conventional ICSI group, while the low birthweight (LBW) rate was significantly lower compared with the conventional ICSI group but similar with the IVF subgroup. No other differences were observed among the three groups for cumulative clinical pregnancy rate, cumulative live birth rate, and the pregnancy outcomes per transfer including clinical pregnancy, ectopic pregnancy, miscarriage, and live birth, either in fresh or frozen embryo transfer cycles. Furthermore, neonatal outcomes, including cesarean section, sex ratio, LBW, preterm birth, and macrosomia, were similar among groups.

LIMITATIONS REASONS FOR CAUTION

This study is limited by the retrospective design, limited sample size, and short follow-up period. However, our study underlies the need for large-scale, multi-center randomized controlled trials with long-term follow-up.

WIDER IMPLICATIONS OF THE FINDINGS

Short-term insemination (3 h) combined with E-RICSI may be a safe and effective method to prevent the occurrence of total fertilization failure, and patients with normal or borderline sperm could be encouraged to try IVF first.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the National Key & Development Program of China (No. 2021YFC2700603) and the National Natural Science Foundation of China (No. 81801443). The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Comparing the pregnancy outcomes of Re‑ICSI and ICSI embryos in fresh ET and FET cycles

Early rescue intracytoplasmic sperm injection (Re-ICSI) can prevent total fertilization failure (TFF) during conventional in vitro fertilization (IVF). However, the implantation rate of Re-ICSI embryos is lower than that of direct ICSI during fresh embryo transfer (ET). The aim of the present study was to investigate the effect of frozen ET (FET) after Re-ICSI. In the present retrospective study, primary infertility patients that underwent the first Re-ICSI and ICSI treatment, were studied. The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed between the Re-ICSI and ICSI groups in fresh ET and FET cycles. The average age of patients between Re-ICSI and ICSI groups in fresh ET and FET cycles was (29.0±3.2 vs. 29.1±3.1, and 29.1±3.3 vs. 28.9±3.0), respectively (P>0.05). Compared with ICSI embryos, the clinical pregnancy, implantation and live birth rates of Re-ICSI embryos were lower in fresh ET cycles. By contrast, there were no significant differences in the pregnancy, implantation and live birth rates between the Re-ICSI and ICSI embryos during the FET cycles. Re-ICSI coupled with FET may overcome the impaired outcomes in fresh ET.

Safety of early cumulus cell removal combined with early rescue ICSI in the prevention of fertilization failure

RESEARCH QUESTION

What are the clinical outcomes and safety implications of early cumulus cell removal after short-term insemination combined with early rescue intracytoplasmic sperm injection (ICSI) in preventing fertilization failure?

DESIGN

In this retrospective study, a total of 14,360 cycles were divided into four groups based on insemination method and fertilization ability: conventional IVF group (n = 5519); early cumulus cell removal group (n = 4107); conventional ICSI group (n = 4215); and early rescue ICSI group (where failed or low fertilization was predicted, n = 519). Fertilization outcomes, pregnancy outcomes, neonatal outcomes and birth defects were analysed by comparing the early cumulus cell removal group with the conventional IVF group, and the early rescue ICSI group with the conventional ICSI group.

RESULTS

There were no significant differences in the outcomes of fertilization, pregnancy, neonates or birth defects between the conventional IVF group and the early cumulus cell removal group (P > 0.05). When compared with the conventional ICSI group, the early rescue ICSI group had similar rates of two pronuclei (2PN) at fertilization, clinical pregnancy, miscarriage, ectopic pregnancy, live birth, sex, mean gestational age, very low birthweight, macrosomia and birth defects (P > 0.05) but a higher polyploidy rate, lower high-quality embryo rate (both P < 0.001), lower twin pregnancy rate (P < 0.01), lower rate of low birthweight, and a higher rate of normal birthweight (both P = 0.024).

CONCLUSIONS

Early cumulus cell removal combined with early rescue ICSI led to good pregnancy and neonatal outcomes without an increase in birth defects. This approach could therefore be an effective and safe method for patients with fertilization failure in conventional IVF.

A novel frameshift mutation in DNAH6 associated with male infertility and asthenoteratozoospermia

Introduction

Asthenoteratozoospermia is one of the most common causes of male infertility. Several genes have been identified as genetic causative factors, but there is a considerable genetic heterogeneity underlying asthenoteratozoospermia. In this study, we performed a genetic analysis of two brothers from a consanguineous Uighur family in China to identify gene mutations causative for asthenoteratozoospermia-related male infertility.

Methods

Two related patients with asthenoteratozoospermia from a large consanguineous family were sequenced by whole-exome sequencing and Sanger sequencing to identify disease-causing genes. Scanning and transmission electron microscopy analysis revealed ultrastructural abnormalities of spermatozoa. Quantitative real-time PCR (qRT-PCR) analysis and immunofluorescence (IF) analysis were used to assess the expression of the mutant messenger RNA (mRNA) and protein.

Results

A novel homozygous frameshift mutation (c.2823dupT, p.Val942Cysfs*21) in DNAH6 was identified in both affected individuals and was predicted to be pathogenic. Papanicolaou staining and electron microscopy revealed multiple morphological and ultrastructural abnormalities of affected spermatozoa. qRT-PCR and IF analysis showed abnormal expression of DNAH6 in affected sperm, probably due to premature termination code and decay of abnormal 3' untranslated region (UTR) region of mRNA. Furthermore, intracytoplasmic sperm injection could achieve successful fertilization in infertile men with DNAH6 mutations.

Discussion

The novel frameshift mutation identified in DNAH6 may contribute to asthenoteratozoospermia. These findings expand the spectrum of genetic mutations and phenotypes associated with asthenoteratozoospermia and may be useful for genetic and reproductive counseling in male infertility.

The role of maternal physical activity on in vitro fertilization outcomes: a systematic review and meta-analysis

PURPOSE

This systematic review is designed to summarize the evidence concerning the impact of maternal physical activity on the reproductive outcomes following assisted reproduction techniques (ART), namely in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

METHODS

We searched for eligible studies on PubMed, EMBASE databases and the Cochrane Library from their inception until September 2021. Our primary outcomes were live birth rate and miscarriage, while secondary ones included clinical pregnancy and implantation rates. The quality of the evidence was evaluated using a study-specific adaptation of the Robins I tool.

RESULTS

Quantitative data from 10 cohort studies (CS) and 2 randomized control trials (RCT), involving 3431 women undergoing ART treatments, were included in the analyses. The pooled results exhibited uncertainty regarding the effect of physical activity on live birth rate per woman (OR 1.15, 95% CI 0.92-1.43, p = 0.23, I² = 61%, 9 studies) and miscarriage rates (OR 0.79, 95% CI 0.44-1.43, p = 0.43, I² = 44%, 6 studies). However, physical activity was associated with significantly improved clinical pregnancy rate after ART (OR 1.39, 95% CI 1.08-1.79, p = 0.0009, I² = 68%, 10 studies), whereas implantation rate after ART almost reached statistical significance (OR = 1.95, 95% CI 0.99-3.82, p = 0.05, I² = 77%).

CONCLUSION

The current evidence is still insufficient to firmly conclude on the effect of maternal physical activity on live birth, miscarriage and implantation rates. Although clinical pregnancy rates favored physical activity in this group of patients, these results must be undertaken with caution due to the low quality and the high heterogeneity of the studies included.