Risk of birth defects in children conceived by artificial oocyte activation and intracytoplasmic sperm injection: a meta-analysis

Add-On Technologies That Aim to Improve Oocyte Quality and Embryo Implantation Potential

Advancements in assisted reproductive technologies (ARTs) have led to the development of various add-on techniques aimed at improving oocyte quality and enhancing embryo implantation potential. These techniques target critical stages of both oocyte and embryo physiology, including oocyte growth and maturation, fertilization, chromosomal status, and embryo development. Key approaches involve the optimization of in vitro fertilization (IVF) protocols, recruiting capable follicles giving rise to dynamic oocytes to evolve, culture media supplementation, preimplantation genetic testing (PGT), and mitochondrial replacement therapy (MRT), all of which are designed to enhance oocyte competence through its function and metabolism. The use of PGT has been promising in selecting embryos suitable for transfer, thus optimizing implantation success. Emerging technologies, such as platelet-rich plasma treatment (PRP), time-lapse imaging (TLI), and hyaluronan-rich (HA) culture media, claim to improve ovarian rejuvenation and uterine receptivity, embryo selection, as well as embryo implantation potential, respectively. Evidence for certain add-on approaches remains limited, but ongoing research suggests that the use of such treatments may lead to increased clinical pregnancies and live birth rates, especially in poor-prognosis patients. The present review describes the current state of the add-on innovations, their mechanisms of action, as well as their possibilities to increase ART success rates.

Assessing the impact of calcium ionophore on pregnancy outcomes in artificial oocyte activation cycles: a 10-year update of systematic review and meta-analysis

PURPOSE

The objective is to evaluate the effectiveness and safety of calcium ionophore as an artificial oocyte activation (AOA) method on pregnancy outcomes in different groups of intracytoplasmic sperm injection (ICSI) patients, providing potential evidence to establish consensus on the indications of AOA.

METHODS

A systematic comprehensive search was performed in Medline, Embase, the Cochrane Library, and Google Scholar databases. Studies published from January 2014 to June 2024 were searched for analysis. All studies that compared ICSI with AOA-ICSI in routine indications composing impaired fertilization or embryo developmental arrest in previous cycles, or male-factor infertility were included.

RESULTS

Twelve studies were included in the meta-analysis. AOA-ICSI was associated with the increase in the overall fertilization rate (OR 1.99, 95% CI 1.16-3.41) and live birth rate (OR 4.58, 95% CI 1.52-13.80). All secondary outcomes including cleavage, blastocyst, high-quality embryo, implantation, biochemical pregnancy, clinical pregnancy presented superiority or equivalence in AOA-ICSI. And the use of calcium ionophore did not increase the miscarriage rate (OR 0.43, 95% CI 0.08-2.43). In subgroup analysis, AOA-ICSI exhibited a more significant effect on patients with indications of no or low fertilization. However, in patients with non-fertilization factors, no statistically significant improvements were observed in all outcomes.

CONCLUSION

Calcium ionophore is an effective artificial oocyte activation approach to improving pregnancy outcomes after ICSI, particularly in cases with indications of fertilization factors, providing further support for the application of AOA in specific populations. Further validation is needed to comprehensively establish the safety of AOA.

TRIAL REGISTRATION

PROSPERO registration number CRD42024551481.

Artificial oocyte activation improves ICSI outcomes following unexplained fertilization abnormalities

RESEARCH QUESTION

Is artificial oocyte activation (AOA) effective for patients with unexplained low or no fertilization following IVF/intracytoplasmic sperm injection (ICSI)?

DESIGN

All IVF/ICSI cases resulting in total fertilization failure or fertilization rate ≤25% at Ninewells Assisted Conception Unit, Dundee between January 2014 and December 2021 (n = 231) were reviewed contemporaneously. After exclusion of obvious stimulation, egg, sperm and/or assisted reproductive technology laboratory factors, patients with at least one cycle of IVF/ICSI resulting in apparently unexplained fertilization abnormalities were offered research investigations, including sperm immunocytochemistry for phospholipase C zeta (PLCζ) protein expression. This retrospective case-control cohort study evaluated laboratory and clinical outcomes for 39 couples (15 attended for sperm studies research) that subsequently undertook ICSI-AOA with Ca2+ ionophore.

RESULTS

Comparing preceding IVF/ICSI and subsequent ICSI-AOA for each patient, the number of eggs collected was similar; however, ICSI-AOA resulted in a significantly improved fertilization rate (57.2% versus 7.1%; P < 0.0001). The uplift for a subset of 10 patients identified with PLCζ deficiency was 66.3% versus 4.6% (P < 0.0001). Overall, ICSI-AOA resulted in a higher number of fresh embryo transfers (94.6% versus 33.3%; P < 0.0001), a significantly higher clinical pregnancy rate (CPR) and live birth rate (LBR; 18.9% versus 2.6%; P = 0.02), a significant increase in cycles with surplus embryos suitable for cryostorage (43.6% versus 0%; P < 0.0001), and increased cumulative CPR (41.0% versus 2.6%; P < 0.0001) and LBR (38.5% versus 2.6%; P < 0.0001).

CONCLUSION

AOA is a powerful tool that can transform clinical outcomes for couples experiencing apparently unexplained fertilization abnormalities. PLCζ assays have the potential to be valuable diagnostic tools to determine patient selection for ICSI-AOA, and research efforts should continue to focus on their development.

Aggressive sperm immobilization improves reproductive outcomes in patients with suboptimal semen parameters and previous ICSI fertilization failure

Intracytoplasmic sperm injection (ICSI) is the most effective procedure to resolve male infertility, enhancing overall fertilization and pregnancy outcomes. However, it is important to note that fertilization failure (FF) can still occur in a few cases after ICSI. This study aims to introduce a specialized technique of aggressive sperm immobilization for ICSI and evaluate its impact on reproductive outcomes in cases involving prior fertilization failure. All infertile couples with male partners having suboptimal semen samples and previous ICSI fertilization failure were evaluated using retrospective data from National Taiwan tertiary university hospital (NTUH) between January 2016 and February 2022. Fertilization failure in our study was defined as less than 30% fertilization rate (FR, the number of normally fertilized oocytes divided by the total number of injected mature oocytes). Data involving both standard (routine procedure) and aggressive sperm immobilization (SI) techniques during different ICSI cycles were included in this study. Standard and aggressive SI methods were performed by compressing the distal half tail of the spermatozoa ≦ 5 and 15 times prior to ICSI respectively. Generalized estimating equations analysis were applied to compare the clinical outcomes between two procedures. Overall, data from 23 infertile couples who had undergone 65 ICSI cycles (31 standard SI with low fertilization rate and 34 aggressive SI) were included in the study. The average FR in the ICSI cycles with standard SI and aggressive SI were 23.6 ± 23.1% and 49.5 ± 31.8 respectively (P = 0.0002). The majority of embryos were transferred at the day 3 stage, with an average number transferred of 2.6 ± 0.9 in the aggressive SI group and 1.9 ± 0.9 in the standard group. The number of embryos transferred per transfer cycle was higher in the aggressive SI (P = 0.015), whereas the number of good-quality embryos was similar between the two procedures (P = 0.44). There were one and seven live births from the standard SI cycles and aggressive SI cycles respectively. In conclusion, aggressive SI was associated with a significantly higher FR, resulting in more available embryos for transfer without compromising embryo quality. Therefore, this specialized technique improved pregnancy outcome among infertile couples with a previous ICSI-FF. It can be a safe, economic, and effective method to improve the assisted reproductive technologies outcomes for infertile patients affected by previous ICSI-FF.

Should non-invasive prenatal testing be recommended for patients who achieve pregnancy with PGT?

OBJECTIVE

To determine whether non-invasive prenatal testing is an alternative testing option to preimplantation genetic testing (PGT) in pregnant patients.

METHODS

This was a retrospective study of the clinical outcomes of patients who underwent PGT and invasive or non-invasive pregnancy testing after euploid blastocyst transfer at our IVF centre between January 2017 and December 2022.

RESULTS

In total, 321 patients were enrolled in this study, 138 (43.0%) received invasive pregnancy testing, and 183 (57.0%) patients underwent non-invasive testing. The mean age of the patients in Group 2 was higher than that of the patients in Group 1 (35.64 ± 4.74 vs. 31.04 ± 4.15 years, P < 0.001). The basal LH and AMH levels were higher in Group 1 than in Group 2 (4.30 ± 2.68 vs. 3.40 ± 1.88, P = 0.003; 5.55 ± 11.22 vs. 4.09 ± 3.55, P = 0.012), but the clinical outcomes were not significantly different. Furthermore, the clinical outcomes of patients undergoing invasive testing were similar to those of patients undergoing non-invasive testing with the same PGT indication.

CONCLUSION

Our results suggest that non-invasive pregnancy testing is a suitable alternative option for detecting the foetal chromosomal status in a PGT cycle. However, the usefulness of non-invasive testing in PGT-M patients is still limited.

Good practice recommendations on add-ons in reproductive medicine†

STUDY QUESTION

Which add-ons are safe and effective to be used in ART treatment?

SUMMARY ANSWER

Forty-two recommendations were formulated on the use of add-ons in the diagnosis of fertility problems, the IVF laboratory and clinical management of IVF treatment.

WHAT IS KNOWN ALREADY

The innovative nature of ART combined with the extremely high motivation of the patients has opened the door to the wide application of what has become known as 'add-ons' in reproductive medicine. These supplementary options are available to patients in addition to standard fertility procedures, typically incurring an additional cost. A diverse array of supplementary options is made available, encompassing tests, drugs, equipment, complementary or alternative therapies, laboratory procedures, and surgical interventions. These options share the common aim of stating to enhance pregnancy or live birth rates, mitigate the risk of miscarriage, or expedite the time to achieving pregnancy.

STUDY DESIGN, SIZE, DURATION

ESHRE aimed to develop clinically relevant and evidence-based recommendations focusing on the safety and efficacy of add-ons currently used in fertility procedures in order to improve the quality of care for patients with infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ESHRE appointed a European multidisciplinary working group consisting of practising clinicians, embryologists, and researchers who have demonstrated leadership and expertise in the care and research of infertility. Patient representatives were included in the working group. To ensure that the guidelines are evidence-based, the literature identified from a systematic search was reviewed and critically appraised. In the absence of any clear scientific evidence, recommendations were based on the professional experience and consensus of the working group. The guidelines are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines were reviewed by 46 independent international reviewers. A total of 272 comments were received and incorporated where relevant.

MAIN RESULTS AND THE ROLE OF CHANCE

The multidisciplinary working group formulated 42 recommendations in three sections; diagnosis and diagnostic tests, laboratory tests and interventions, and clinical management.

LIMITATIONS, REASONS FOR CAUTION

Of the 42 recommendations, none could be based on high-quality evidence and only four could be based on moderate-quality evidence, implicating that 95% of the recommendations are supported only by low-quality randomized controlled trials, observational data, professional experience, or consensus of the development group.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines offer valuable direction for healthcare professionals who are responsible for the care of patients undergoing ART treatment for infertility. Their purpose is to promote safe and effective ART treatment, enabling patients to make informed decisions based on realistic expectations. The guidelines aim to ensure that patients are fully informed about the various treatment options available to them and the likelihood of any additional treatment or test to improve the chance of achieving a live birth.

STUDY FUNDING/COMPETING INTEREST(S)

All costs relating to the development process were covered from ESHRE funds. There was no external funding of the development process or manuscript production. K.L. reports speakers fees from Merck and was part of a research study by Vitrolife (unpaid). T.E. reports consulting fees from Gynemed, speakers fees from Gynemed and is part of the scientific advisory board of Hamilton Thorne. N.P.P. reports grants from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare, speakers fees from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare. S.R.H. declares being managing director of Fertility Europe, a not-for-profit organization receiving financial support from ESHRE. I.S. is a scientific advisor for and has stock options from Alife Health, is co-founder of IVFvision LTD (unpaid) and received speakers' fee from the 2023 ART Young Leader Prestige workshop in China. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S, consulting fees from Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos and Merck A/S, speakers fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S, Theramex and Organon, travel fees from Gedeon Richter. The other authors disclosed no conflicts of interest.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation.ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or bedeemedinclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results.Theydo not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

Artificial oocyte activation with Ca2+ ionophore improves reproductive outcomes in patients with fertilization failure and poor embryo development in previous ICSI cycles

Research question

Does artificial oocyte activation (AOA) by a calcium ionophore (ionomycin) improve the previous fertilization failure or poor embryo development of intracytoplasmic sperm injection (ICSI) account for male factor infertility or other infertility causes?

Design

This retrospective study involved 114 patients receiving ICSI-AOA in Shanghai First Maternity and Infant Hospital with previous ICSI fertilization failure or poor embryo development. The previous ICSI cycles of the same patients without AOA served as the control group. The fertilization rates, cleavage rates, transferable embryo rates and blastocyst formation rates of the two groups were compared. Additionally, the clinical pregnancy, implantation rate and live birth rates were also compared to assess the efficiency and safety of AOA. Furthermore, two subgroup analyses were performed in this study based on the cause of infertility and the reason for AOA. The fertilization rate, embryonic development potential and clinical outcome were compared among groups.

Results

Among 114 ICSI-AOA cycles, the fertilization rate, top-quality embryo rate, implantation rate, clinical pregnancy per patient and live birth rate per patient were improved significantly compared with previous ICSI cycles (p<0.05 to P< 0.001), and the miscarriage rate in the AOA group was significantly lower than that of the control group (p<0.001). In the AOA subgroups based on the cause of infertility, the fertilization rates of each subgroup were significantly improved compared with previous control cycles except for the mixed factor infertility subgroup (p<0.05 to p<0.001). In the AOA subgroups based on the reason for AOA, the fertilization rates of each subgroup were significantly increased compared with those in their previous ICSI cycle without AOA (p<0.001); however, there was no significant difference in the top-quality embryo rate. No significant improvement was found in the implantation rates and the clinical pregnancy rate in each subgroup except for the poor embryo development subgroup. In the 114 AOA cycles, 35 healthy infants (21 singletons and 7 twins) were delivered without major congenital birth defects or malformations.

Conclusion

This study showed that AOA with the calcium ionophore ionomycin can improve the reproductive outcomes of patients with previous fertilization failure and poor embryo development after ICSI.

Advances in the study of genetic factors and clinical interventions for fertilization failure

Fertilization failure refers to the failure in the pronucleus formation, evaluating 16-18 h post in vitro fertilization or intracytoplasmic sperm injection. It can be caused by sperm, oocytes, and sperm-oocyte interaction and lead to great financial and physical stress to the patients. Recent advancements in genetics, molecular biology, and clinical-assisted reproductive technology have greatly enhanced research into the causes and treatment of fertilization failure. Here, we review the causes that have been reported to lead to fertilization failure in fertilization processes, including the sperm acrosome reaction, penetration of the cumulus and zona pellucida, recognition and fusion of the sperm and oocyte membranes, oocyte activation, and pronucleus formation. Additionally, we summarize the progress of corresponding treatment methods of fertilization failure. This review will provide the latest research advances in the genetic aspects of fertilization failure and will benefit both researchers and clinical practitioners in reproduction and genetics.

The effect of ionomycin-induced oocyte activation on multiple morphological abnormalities of the sperm flagella

Artificial oocyte activation (AOA) is considered an effective method to improve clinical outcomes in patients with some forms of male factor infertility and does not increase the risk of birth defects. However, the effects of AOA on patients with multiple morphological abnormalities of the sperm flagella (MMAF) caused by a DNAH1 mutation are still unknown. To explore the effects, our study analyzed a case with MMAF due to DNAH1 homozygous mutation that underwent testicular sperm extraction (TESE) combined with intracytoplasmic sperm injection (ICSI). The case had 28 MII oocytes. The 28 oocytes were divided randomly and equally into AOA and non-AOA groups. Ionomycin was used for AOA. We compared the clinical outcomes of two groups and selected three blastulation failure embryos from each group for transcriptome analysis (Data can be accessed through GSE216618). Differentially expressed genes (DEGs) were determined with an adjusted p-value <0.05 and a |log2-fold change| ≥1. The comparison of clinical outcomes showed that the two pronuclei (2PN) rate and grade 1-2 embryo rate at day 3 were not significantly different between the two groups. Transcriptome analyses of blastulation failed embryos showed that the use of AOA had potential risks of chromosome structure defects, transcriptional regulation defects, and epigenetic defects. In conclusion, when the case with MMAF due to DNAH1 mutation underwent TESE-ICSI, ionomycin-induced oocyte activation could not improve the clinical outcomes and introduced the risks of chromosome structure defect, transcriptional regulation defect, and epigenetic defect.

Assisted Oocyte Activation following Intracytoplasmic Sperm Injection: A Sensible Option for Infertile Couples with Severe Teratozoospermia

The intracytoplasmic sperm injection (ICSI) has significantly improved male factor infertility treatment; however, complete fertilization failure still occurs in 1-5% of ICSI treatment cycles mainly due to oocyte activation failure. It is estimated that around 40-70% of oocyte activation failure is associated with sperm factors after ICSI. Assisted oocyte activation (AOA) as an effective approach to avoid total fertilization failure (TFF) has been proposed following ICSI. In the literature, several procedures have been described to overcome failed oocyte activation. These include mechanical, electrical, or chemical stimuli initiating artificial Ca²⁺ rises in the cytoplasm of oocytes. AOA in couples with previous failed fertilization and those with globozoospermia has resulted in varying degrees of success. The aim of this review is to examine the available literature on AOA in teratozoospermic men undergoing ICSI-AOA and determine whether the ICSI-AOA should be considered as an adjunct fertility procedure for these patients.

Prenatal diagnosis of fetuses conceived by assisted reproductive technology by karyotyping and chromosomal microarray analysis

Background

Invasive prenatal evaluation by chromosomal microarray analysis (CMA) and karyotyping might represent an important option in pregnant women, but limited reports have applied CMA and karyotyping of fetuses conceived by assisted reproductive technology (ART). This study aimed to examine the value of CMA and karyotyping in prenatal diagnosis after ART.

Methods

This retrospective study included all singleton fetuses conceived by ART from January 2015 to December 2021. Anomalies prenatally diagnosed based on karyotyping and CMA were analyzed. Prevalence rates for various CMA and karyotyping results were stratified based on specific testing indications including isolated-and non-isolated ART groups. The rates of CMA findings with clinical significance (pathogenic/likely pathogenic) and karyotype anomalies were assessed and compared to those of local control individuals with naturally conceived pregnancies and without medical indications.

Results

In total, 224 subjects were assessed by karyotyping and CMA. In the examined patients, chromosomal and karyotype abnormality rates were 3.57% (8/224) and 8.93% (20/224), respectively. This finding indicated a 5.35% (12/224)-incremental rate of abnormal CMA was obtained over karyotype analysis (p = 0.019). The risk of CMA with pathogenic findings for all pregnancies conceived by ART (5.80%, 13/224) was markedly elevated in comparison with the background value obtained in control individuals (1.47%, 9/612; p = 0.001). In addition, risk of CMA with clinically pathogenic results in isolated ART groups was significant higher compared to the background risk reported in the control cohort (p = 0.037).

Conclusions

Prenatal diagnosis including karyotyping and CMA is recommended for fetuses conceived by ART, with or without ultrasound findings.

Artificial oocyte activation using Ca2+ ionophores following intracytoplasmic sperm injection for low fertilization rate

This large multi-center retrospective study examined whether artificial oocyte activation (AOA) using Ca²⁺ ionophore following ICSI improves the live birth rate for couples with previous ICSI cycles of unexplained low fertilization rate. In this large-scale multi-center retrospective study conducted in Japan, data were collected from Keio University and 17 collaborating institutions of the Japanese Institution for Standardizing Assisted Reproductive Technology. Between January 2015 and December 2019, 198 couples were included in this study. Oocytes for both the intervention and control groups were procured from the same pool of couples. Oocytes obtained from ICSI cycles with no or low fertilization rate (<50%) with unknown causes were included in the control (conventional ICSI) group while oocytes procured from ICSI cycles followed by performing AOA were assigned to the intervention (ICSI-AOA) group. Those fertilized with surgically retrieved sperm were excluded. ICSI-AOA efficacy and safety were evaluated by comparing these two groups. Live birth rate was the primary outcome. The ICSI-AOA group (2,920 oocytes) showed a significantly higher live birth per embryo transfer rate (18.0% [57/316]) compared to that of the conventional ICSI group with no or low fertilization rate (1,973 oocytes; 4.7% [4/85]) (odds ratio 4.5, 95% confidence interval 1.6-12.6; P<0.05). A higher live birth rate was observed in younger patients without a history of oocyte retrieval. Miscarriage, preterm delivery, and fetal congenital malformation rates were similar between the two groups. ICSI-AOA may reduce fertilization failure without increasing risks during the perinatal period. AOA may be offered to couples with an ICSI fertilization rate < 50%.

Common dysmorphic oocytes and embryos in assisted reproductive technology laboratory in association with gene alternations

Amorphic or defected oocytes and embryos are commonly observed in assisted reproductive technology (ART) laboratories. It is believed that a proper gene expression at each stage of embryo development contributes to the possibility of a decent-quality embryo leading to successful implantation. Many studies reported that several defects in embryo morphology are associated with gene expressions during in vitro fertilization (IVF) treatment. There is lacking literature review on summarizing common morphological defects about gene alternations. In this review, we summarized the current literature. We selected 64 genes that have been reported to be involved in embryo morphological abnormalities in animals and humans, 30 of which were identified in humans and might be the causes of embryonic changes. Five papers focusing on associations of multiple gene expressions and embryo abnormalities using RNA transcriptomes were also included during the search. We have also reviewed our time-lapse image database with over 3000 oocytes/embryos to show morphological defects possibly related to gene alternations reported previously in the literature. This holistic review can better understand the associations between gene alternations and morphological changes. It is also beneficial to select important biomarkers with strong evidence in IVF practice and reveal their potential application in embryo selection. Also, identifying genes may help patients with genetic disorders avoid unnecessary treatments by providing preimplantation genetic testing for monogenic/single gene defects (PGT-M), reduce embryo replacements by less potential, and help scientists develop new methods for oocyte/embryo research in the near future.

Oocyte Donation: Three Perspectives

Background: A number of important problems remain unresolved in the field of assisted reproductive technologies (ART) using germ cells from a single donor. This study aimed to assess attitudes about the use of sex gamete donation in ART in different social groups including medical workers, oocyte recipients, and oocyte donors. Methods: To achieve this goal, we surveyed 286 participants from seven countries. Of them, 190 were medical workers from ART clinics (respondents from seven countries), 45 were oocyte recipients (Kazakhstan), and 51 were oocyte donors (Kazakhstan). Results: A survey of the three groups showed that issues related to donor health were most common in the donor selection process based on patient and doctor distrust of the health care system. The main motive for oocyte donation was financial compensation, which draws attention to the social disadvantage of the donor population. Medical workers with more than 5 years of work experience (79.7%) supported the use of programs tracking donor sex gametes and limiting the use of oocyte donors. Conclusions: The willingness and consent of the surveyed medical workers and oocyte recipients to use the donor material and create a unified registry of donor sex gametes demonstrates the importance of this issue.

Artificial Egg Activation Using Calcium Ionophore

Artificial oocyte activation, most commonly using calcium ionophore, is a treatment add-on utilized to avoid recurrence of abnormally low or total failed fertilization following in vitro fertilization/intracytoplasmic sperm injection. It aims to modify defective physiological processes, specifically calcium-mediated cell signaling that are critical to events required for fertilization. Routine application of artificial oocyte activation is neither required nor recommended; however, it represents an invaluable intervention for a subgroup of patients affected by sperm-related oocyte activation deficiency.

The efficacy of add-ons: selected IVF "add-on" procedures and future directions

Since the advent of ART, technology has continuously evolved to improve embryology and pregnancy outcomes. However, not all technologies that are integrated into practice have convincing evidence of clinical effectiveness, and they often increase the financial burden of fertility care. We discuss here a selection of commonly utilized IVF "add-ons" and discuss the existing evidence for their utility. The procedures included in this review are time-lapse imaging of embryos, assisted hatching, EmbryoGlue, sperm DNA testing, egg activation with calcium ionophore, endometrial receptivity array, and physiological intracytoplasmic sperm injection (PICSI). While there is rather limited supporting evidence for nearly all IVF add-ons that we reviewed, there is strong demand from patients, physicians, and the biotechnology industry to continue further research and development in this arena. We propose that all add-on procedures should provide true efficacy for the patient, and reproductive endocrinologists should inform patients of the costs and benefits of utilizing various technologies before they undergo treatment. In the future, add-ons that show clear evidence of efficacy and justifiable cost should be incorporated into routine practice, while others that do not meet these criteria should be phased out entirely.

Molecular Drivers of Developmental Arrest in the Human Preimplantation Embryo: A Systematic Review and Critical Analysis Leading to Mapping Future Research

Developmental arrest of the preimplantation embryo is a multifactorial condition, characterized by lack of cellular division for at least 24 hours, hindering the in vitro fertilization cycle outcome. This systematic review aims to present the molecular drivers of developmental arrest, focusing on embryonic and parental factors. A systematic search in PubMed/Medline, Embase and Cochrane-Central-Database was performed in January 2021. A total of 76 studies were included. The identified embryonic factors associated with arrest included gene variations, mitochondrial DNA copy number, methylation patterns, chromosomal abnormalities, metabolic profile and morphological features. Parental factors included, gene variation, protein expression levels and infertility etiology. A valuable conclusion emerging through critical analysis indicated that genetic origins of developmental arrest analyzed from the perspective of parental infertility etiology and the embryo itself, share common ground. This is a unique and long-overdue contribution to literature that for the first time presents an all-inclusive methodological report on the molecular drivers leading to preimplantation embryos’ arrested development. The variety and heterogeneity of developmental arrest drivers, along with their inevitable intertwining relationships does not allow for prioritization on the factors playing a more definitive role in arrested development. This systematic review provides the basis for further research in the field.

A Novel Assisted Oocyte Activation Method Improves Fertilization in Patients With Recurrent Fertilization Failure

Total fertilization failure (TFF) occurs in 1–3% of total intracytoplasmic sperm injection (ICSI) cycles and can reoccur in subsequent cycles. Despite the high success rate with the application of assisted oocyte activation (AOA), there is still a small number of couples who cannot obtain fertilized eggs after conventional calcium (Ca²⁺) ionophores-based ICSI-AOA. Six couples experiencing repeated TFF or low fertilization (<10%) after ICSI and conventional ICSI-AOA were enrolled in this study. Compared with the regular ICSI group and the conventional ICSI-AOA group, the new AOA method, a combination of cycloheximide (CHX) and ionomycin, can significantly increase the fertilization rate from less than 10 up to approximately 50% in most cases. The normal distribution of sperm-related oocyte activation factor phospholipase C zeta (PLCζ1) in the sperms of the cases indicated the absence of an aberrant Ca²⁺ signaling activation. The results of the whole-embryo aneuploidies analysis indicated that oocytes receiving the novel AOA treatment had the potential to develop into blastocysts with normal karyotypes. Our data demonstrated that CHX combined with ionomycin was able to effectively improve the fertilization rate in the majority of patients suffering from TFF. This novel AOA method had a potential therapeutic effect on those couples experiencing TFF, even after conventional AOA, which may surmount the severe fertilization deficiencies in patients with a repeated low fertilization or TFF.

Obstetrical and Neonatal Outcomes of 3,028 Singletons Born After Advanced ART Techniques: Ejaculated Sperm Intracytoplasmic Sperm Injection, Artificial Oocyte Activation, in Vitro Maturation and Testicular Sperm Extraction

Background: To evaluate obstetrical and neonatal outcomes of singletons conceived after advanced assisted reproductive technology (ART) techniques: conventional IVF pregnancies (C-IVF), ejaculated sperm intracytoplasmic sperm injection (ICSI), assisted oocyte activation (AOA), in vitro maturation (IVM), and testicular sperm extraction (TESE).

Methods: The subjects were 3,028 singletons who were born after fresh or frozen embryo transfer. The subjects were separated into five groups: C-IVF (n = 855), ICSI (n = 1,869), AOA (n = 42), IVM (n = 32), and TESE (n = 230). We evaluated obstetrical and neonatal outcomes calculating the adjusted odds ratio (AOR) using multivariable logistic regression analyses for fresh and frozen embryos and for cleavage and blastocyst transfer. The C-IVF group was used as a background control for the ICSI group. Moreover, the TESE, AOA, and IVM groups were compared to the ICSI group to evaluate the effects of the ICSI procedure itself.

Results: The incidence of perinatal complications was significantly lower in the ICSI-fresh group (AOR = 0.29, 95% CI: 0.10–0.83, p ¡ 0.05). Regarding sex ratio, the IVM was significantly associated with sex ratio imbalance toward female in both fresh and frozen groups (AOR = 0.30, 95% CI: 0.10–0.96, AOR = 0.27, 95% CI: 0.07–0.98, p ¡ 0.05). On the other hand, there were no significant differences in preterm birth rate, low birth weight rate and congenital abnormalities rate between conventional IVF, ICSI, and the other groups.

Conclusions: There were no negative effects on obstetrical and neonatal outcomes between conventional IVF and ICSI. Although this was a limited sample size study, advanced ART technologies such as AOA, IVM, and TESE also seem to have a low risk of adverse impact on obstetrical and neonatal outcomes but may have a slight impact on sex ratio.