Rescue intracytoplasmic sperm injection: a systematic review

Predictive models of recurrent implantation failure in patients receiving ART treatment based on clinical features and routine laboratory data

STUDY QUESTION

The objective was to construct a model for predicting the probability of recurrent implantation failure (RIF) after assisted reproductive technology (ART) treatment based on the clinical characteristics and routine laboratory test data of infertile patients. A model was developed to predict RIF. The model showed high calibration in external validation, helped to identify risk factors for RIF, and improved the efficacy of ART therapy.

WHAT IS KNOWN ALREADY

Research on the influencing factors of RIF has focused mainly on embryonic factors, endometrial receptivity, and immune factors. However, there are many kinds of examinations regarding these aspects, and comprehensive screening is difficult because of the limited time and economic conditions. Therefore, we should try our best to analyse the results of routine infertility screenings to make general predictions regarding the occurrence of RIF.

STUDY DESIGN, SIZE, DURATION

A retrospective study was conducted with 5212 patients at the Reproductive Center of the First Affiliated Hospital of USTC from January 2018 to June 2022.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study included 462 patients in the RIF group and 4750 patients in the control group. The patients' basic characteristics, clinical treatment data, and laboratory test indices were compared. Logistic regression was used to analyse RIF-related risk factors, and the prediction model was evaluated by receiver operating characteristic (ROC) curves and the corresponding areas under the curve (AUCs). Further analysis of the influencing factors of live births in the first cycle of subsequent assisted reproduction treatment in RIF patients was performed, including the live birth subgroup (n = 116) and the no live birth subgroup (n = 200).

MAIN RESULTS AND THE ROLE OF CHANCE

(1) An increased duration of infertility (1.978; 95% CI, 1.264-3.097), uterine cavity abnormalities (2.267; 95% CI, 1.185-4.336), low AMH levels (0.504; 95% CI, 0.275-0.922), insulin resistance (3.548; 95% CI, 1.931-6.519), antinuclear antibody (ANA)-positive status (3.249; 95% CI, 1.20-8.797) and anti-β2-glycoprotein I antibody (A-β2-GPI Ab)-positive status (5.515; 95% CI, 1.481-20.536) were associated with an increased risk of RIF. The area under the curve of the logistic regression model was 0.900 (95% CI, 0.870-0.929) for the training cohort and 0.895 (95% CI, 0.865-0.925) for the testing cohort. (2) Advanced age (1.069; 95% CI, 1.015-1.126) was a risk factor associated with no live births after the first cycle of subsequent assisted reproduction treatment in patients with RIF. Blastocyst transfer (0.365; 95% CI = 0.181-0.736) increased the probability of live birth in subsequent cycles in patients with RIF. The area under the curve of the logistic regression model was 0.673 (95% CI, 0.597-0.748).

LIMITATIONS, REASONS FOR CAUTION

This was a single-centre regression study, for which the results need to be evaluated and verified by prospective large-scale randomized controlled studies. The small sample size for the analysis of factors influencing pregnancy outcomes in subsequent assisted reproduction cycles for RIF patients resulted in the inclusion of fewer covariates, and future studies with larger samples and the inclusion of more factors are needed for assessment and validation.

WIDER IMPLICATIONS OF THE FINDINGS

Prediction of embryo implantation prior to transfer will facilitate the clinical management of patients and disease prediction and further improve ART treatment outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the General Project of the National Natural Science Foundation of China (Nos. 82,201,792, 82,301,871, 81,971,446, and 82,374,212) and the Natural Science Foundation of Anhui Province (No. 2208085MH206). There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

This study was registered with the Chinese Clinical Trial Register (Clinical Trial Number: ChiCTR1800018298 ).

Early cumulus cell removal increases cumulative live birth rate while having no negative effect on the malformation rate in in vitro fertilization: a propensity score-matched cohort study

PURPOSE

The aim of this study was to investigate the efficacy and safety of early cumulus cell removal (ECCR) during human in vitro fertilization (IVF).

METHODS

A retrospective analysis was performed between January 2011 and December 2019. The study enrolled 1131 couples who underwent IVF treatment with ECCR. After propensity score matching at a 1:1 ratio, 1131 couples who underwent overnight coincubation of gametes were selected. The main outcome measure was the cumulative live birth rate. Secondary outcome measures included the cumulative pregnancy rate, polyspermy rate, available embryo rate, miscarriage rate, malformation rate, time to live birth, and oocyte-to-baby rate.

RESULTS

There were no significant differences found between the two groups in the polyspermy rate, available embryo rate, miscarriage rate, time to live birth, oocyte-to-baby rate, and neonatal congenital anomalies rate. The results of the study showed that ECCR was associated with a significantly higher cumulative live birth rate and cumulative pregnancy rate, along with a significantly lower fertilization rate.

CONCLUSIONS

ECCR tended to confer increased cumulative live birth rate and had no negative effect on the neonatal malformation rate.

Cordycepin delays postovulatory aging of oocytes through inhibition of maternal mRNAs degradation via DCP1A polyadenylation suppression

Postovulatory aging leads to the decline in oocyte quality and subsequent impairment of embryonic development, thereby reducing the success rate of assisted reproductive technology (ART). Potential preventative strategies preventing oocytes from aging and the associated underlying mechanisms warrant investigation. In this study, we identified that cordycepin, a natural nucleoside analogue, promoted the quality of oocytes aging in vitro, as indicated by reduced oocyte fragmentation, improved spindle/chromosomes morphology and mitochondrial function, as well as increased embryonic developmental competence. Proteomic and RNA sequencing analyses revealed that cordycepin inhibited the degradation of several crucial maternal proteins and mRNAs caused by aging. Strikingly, cordycepin was found to suppress the elevation of DCP1A protein by inhibiting polyadenylation during postovulatory aging, consequently impeding the decapping of maternal mRNAs. In humans, the increased degradation of DCP1A and total mRNA during postovulatory aging was also inhibited by cordycepin. Collectively, our findings demonstrate that cordycepin prevents postovulatory aging of mammalian oocytes by inhibition of maternal mRNAs degradation via suppressing polyadenylation of DCP1A mRNA, thereby promoting oocyte developmental competence.

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.

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.

Clinical outcome of different embryo transfer strategies after late rescue ICSI procedure: a 10-year total fertilisation failure cohort study

BACKGROUND

Late rescue intracytoplasmic sperm injection (r-ICSI) has not been widely accepted as an alternative solution for unexpected total fertilisation failure (TFF) after in vitro fertilisation (IVF), due to the time-dependent in vitro deterioration of oocyte quality and endometrial growth not being synchronised with embryo development. This study aimed to evaluate the safety profile and effectiveness of freeze-all blastocyst transfer in combination with late r-ICSI.

METHODS

This was a retrospective cohort study carried out at the Reproductive Centre of Peking University Third Hospital, Beijing, China. All participants received treatment between 2009 and 2019. 2,270 patients in the aggregate encountered unexpected TFF during 149,054 cycles of IVF and adopted a late r-ICSI procedure. Among these patients, 263 women did not have cleavage-stage embryos available for evaluation. The remaining patients were grouped according to different embryo transfer (ET) strategies (926 women in Group 1 underwent fresh ET, 365 women in Group 2 underwent freeze-all ET, 716 women in Group 3 experienced blastulation failure). Patients received different ET strategies after r-ICSI, with the main outcome measures included live birth rate (LBR), cumulative live birth rate (cLBR), and conservative cLBR.

RESULTS

TFF occurred in 7.4% of all IVF cycles. Group 1 tended to be older at oocyte retrieval, with more infertile years, higher follicle-stimulating hormone (FSH) levels, higher gonadotropin consumption, and fewer oocytes retrieved. Group 2 exhibited considerably better LBRs following the first ET cycle (37.53% vs. 4.64%) and cLBRs (52.60% vs. 8.21%). After adjustment for covariates using binary logistic regression analyses, Group 2 still showed better obstetric performance in LBRs [OR:11.77, 95% CI (8.42-16.45)], cLBRs (OR:11.29, 95% CI (7.84-16.27)], and conservative cLBRs (OR:2.55, 95% CI (1.83-3.55)]. Additionally, the two groups showed similar miscarriage rates, whilst no new-borns with malformations or congenital diseases were reported.

CONCLUSIONS

Freeze-all blastocyst stage ET serves as an optimal strategy to support late r-ICSI. However, for women with limited oocytes available for r-ICSI use, weighing the benefits against the costs of the procedure might be prudent before implementing in vitro blastulation.

Fisetin Delays Postovulatory Oocyte Aging by Regulating Oxidative Stress and Mitochondrial Function through Sirt1 Pathway

The quality of oocytes determines the development potential of an embryo and is dependent on their timely fertilization after ovulation. Postovulatory oocyte aging is an inevitable factor during some assisted reproduction technology procedures, which results in poor fertilization rates and impairs embryo development. We found that fisetin, a bioactive flavonol contained in fruits and vegetables, delayed postovulatory oocyte aging in mice. Fisetin improved the development of aged oocytes after fertilization and inhibited the Sirt1 reduction in aged oocytes. Fisetin increased the GSH level and Sod2 transcription level to inhibit ROS accumulation in aged oocytes. Meanwhile, fisetin attenuated aging-induced spindle abnormalities, mitochondrial dysfunction, and apoptosis. At the molecular level, fisetin decreased aging-induced aberrant expression of H3K9me3. In addition, fisetin increased the expression levels of the mitochondrial transcription factor Tfam and the mitochondrial genes Co2 and Atp8 by upregulating Sirt1 in aged oocytes. Finally, inhibition of Sirt1 reversed the anti-aging effects of fisetin. Taken together, fisetin delayed postovulatory oocyte aging by upregulating Sirt1.

The use of ICSI in ART: evidence for practice

This article reviews the evidence regarding the safety and efficacy of intra-cytoplasmic sperm injection (ICSI). It provides evidence-based clinical and laboratory guidelines and recommendations for use of ICSI within an assisted reproductive technology (ART) service. The guidelines address the evidence for the use of ICSI rather than conventional IVF (cIVF); the use of ART techniques supplementary to ICSI; and risks associated with ICSI. This article is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs and medical history of the patient, available resources, and institutional or clinical practice limitations.

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.

Cycle Characteristics and Pregnancy Outcomes of Early Rescue Intracytoplasmic Sperm Injection Cycles in Normal and Hyper-Ovarian Response Women: A Six-Year Retrospective Study

This study aims to analyze the cycle characteristics, pregnancy, and neonatal outcomes in early rescue intracytoplasmic sperm injection (r-ICSI) cycles in normal and hyper-ovarian response women in their first IVF/ICSI attempts. Data from short-term in vitro fertilization (IVF, N = 7148), early r-ICSI (N = 618), and ICSI (N = 1744) cycles were retrospectively analyzed from normal and hyper-ovarian women who underwent their first IVF/ICSI cycles at our center from October 2015 to October 2021. The r-ICSI group was subdivided into partial r-ICSI (N = 451) and total r-ICSI (N = 167) based on the number of fertilized oocytes in the IVF part. Cyclic characteristics, pregnancy, delivery and neonatal outcomes in the fresh cycle were compared among the four groups; pregnancy, delivery and neonatal outcomes in frozen-thawed cycles were compared regarding cleavage and blastocyst transfers derived from r-ICSI cycles. Partial r-ICSI cycles showed different cyclic characteristics compared to total r-ICSI cycles, presenting as elevated AMH and estradiol levels on trigger day and an increased number of oocytes retrieved. Early r-ICSI delayed blastocyst development as seen by the increase in the number of day 6 blastocysts. There was no significant difference among the groups in clinical pregnancy, pregnancy loss, and live birth in fresh cleavage-stage embryo transfer cycles. However, early r-ICSI groups showed a reduction in clinical pregnancy and live birth rates in fresh blastocyst transfer cycles but not in the frozen-thawed cycles. For pregnant women, early r-ICSI did not show a negative effect on the risk of preterm birth, Cesarean section, neonatal birth weight, and sex ratio. In conclusion, early r-ICSI had comparable pregnancy, delivery, and neonatal outcomes when compared with short-term IVF and ICSI groups in fresh cleavage-stage embryo transfer cycles, but early r-ICSI did result in reduced pregnancy outcomes in fresh blastocyst embryo cycles, possibly due to delayed blastocyst development and asynchronization with the endometrium.

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Oxidative stress and in vitro ageing of the post-ovulatory oocyte: an update on recent advances in the field

In brief

Post-ovulatory ageing of oocytes leads to poor oocyte and embryo quality as well as abnormalities in offspring. This review provides an update on the contributions of oxidative stress to this process and discusses the current literature surrounding the use of antioxidant media to delay post-ovulatory oocyte ageing.

Abstract

Following ovulation, the metaphase II stage oocyte has a limited functional lifespan before succumbing to a process known as post-ovulatory oocyte ageing. This progressive demise occurs both in vivo and in vitro and is accompanied by a deterioration in oocyte quality, leading to a well-defined sequelae of reduced fertilisation rates, poor embryo quality, post-implantation errors, and abnormalities in the offspring. Although the physiological consequences of post-ovulatory oocyte ageing have largely been characterised, less is known regarding the molecular mechanisms that drive this process. This review presents an update on the established relationships between the biochemical changes exhibited by the ageing oocyte and the myriad of symptoms associated with the ageing phenotype. In doing so, we consider the molecular events that are potentially involved in orchestrating post-ovulatory ageing with a particular focus on the role of oxidative stress. We highlight the mounting evidence that oxidative stress acts as an initiator for a cascade of events that create the aged oocyte phenotype. Specifically, oxidative stress has the capacity to disrupt mitochondrial function and directly damage multiple intracellular components of the oocyte such as lipids, proteins, and DNA. Finally, this review addresses emerging strategies for delaying post-ovulatory oocyte ageing with emphasis placed on the promise afforded by the use of selected antioxidants to guide the development of media tailored for the preservation of oocyte integrity during in vitro fertilisation procedures.

Opportunities and Limits of Conventional IVF versus ICSI: It Is Time to Come off the Fence

Conventional IVF (c-IVF) is one of the most practiced assisted reproductive technology (ART) approaches used worldwide. However, in the last years, the number of c-IVF procedures has dropped dramatically in favor of intracytoplasmic sperm injection (ICSI) in cases of non-male-related infertility. In this review, we have outlined advantages and disadvantages associated with c-IVF, highlighting the essential steps governing its success, its limitations, the methodology differences among laboratories and the technical progress. In addition, we have debated recent insights into fundamental questions, including indications regarding maternal age, decreased ovarian reserve, endometriosis, autoimmunity, single oocyte retrieval-cases as well as preimplantation genetic testing cycles. The “overuse” of ICSI procedures in several clinical situations of ART has been critically discussed. These insights will provide a framework for a better understanding of opportunities associated with human c-IVF and for best practice guidelines applicability in the reproductive medicine field.

In vitro maturation of human oocytes maintaining good development potential for rescue intracytoplasmic sperm injection with fresh sperm

BACKGROUND

The outcomes of the use of commercial in vitro maturation (IVM) medium to culture immature oocytes obtained from conventional ovulation induction, followed by rescue intracytoplasmic sperm injection (RICSI), are not ideal. It is thus difficult to widely adopt this approach in clinical practice. Therefore, it is necessary to explore methods for improving the clinical outcome of IVM.

AIM

To study the effect of sperm on the developmental potential of in vitro-matured oocytes in conventional culture.

METHODS

This was a retrospective study of patients whose immature oocytes were harvested from conventional oocyte stimulation cycles and underwent ICSI at our hospital between June 2018 and August 2020. RICSI was performed using sperm collected on the day of oocyte harvest (old) and sperm collected on the day of RICSI (fresh) and oocytes matured in vitro after 24 h of culture in conventional medium. The rates of in vitro oocyte maturation, normal fertilization, normal cleavage, day-3 top-quality embryos, and useful blastocyst formation were compared between the two groups.

RESULTS

In total, 102 germinal vesicle (GV)-stage immature oocytes were cultured in the old sperm group. In the fresh sperm group, 122 GV-stage immature oocytes were collected and cultured in vitro for 24 h. There were no significant differences in the general conditions of males and females between the two groups (P > 0.05). The oocyte maturation, normal fertilization, and normal cleavage rates of the old and fresh groups were 51.0% vs 55.7%, 61.5% vs 64.7%, and 93.8% vs 93.2%, respectively. None of the rates differed significantly (P > 0.05) between the two groups. However, the day-3 top-quality embryo and useful blastocyst rates of the old and fresh sperm groups were 16.6% vs 63.4%; 6.67% vs 34.6%, respectively. The day-3 top-quality embryos and useful blastocyst rates of the old sperm group were significantly lower than those of the fresh group (P < 0.05).

CONCLUSION

In vitro maturation with conventional culture medium combined with the use of fresh sperm collected on the day of RICSI is an easy-to-implement strategy for patients whose oocytes are completely or mostly immature.

Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization

Background:

Although rescue intracytoplasmic sperm injection (r-ICSI) is extensively used worldwide, the indication of r-ICSI and its optimal timing remains obscure. This study aimed to assess the outcomes of r-ICSI following in vitro fertilization in different timings when fertilization is confirmed.

Methods:

This study included 5,156 cycles (47,785 eggs). Fertilization was confirmed by polar body analysis after 4 and 6 hr of coincubation of the sperm and oocyte. Oocytes that underwent IVF were divided into two groups based on the time when a second polar body was detected in more than 30% of all oocytes (Four-hr group and six-hr group). If the second polar body was not detected or was present in less than 30% of all oocytes after six hr of coincubation, rescue-ICSI (r-ICSI) was performed for oocytes without a second polar body (r-ICSI group).

Results:

The fertilization rates of two pronuclear (2PN) oocytes in the three groups (Four-hr group, six-hr group, and r-ICSI group) were 70.7%, 51.3%, and 58.0%, respectively. The blastocyst formation rates were 62.8%, 53.4%, and 42.9%, respectively.

Conclusion:

Performing r-ICSI after six hr of coincubation can salvage cases with fertilization failure in IVF. The higher fertilization rate of r-ICSI indicates that all oocytes without signs of fertilization after six hr of coincubation should undergo r-ICSI.

Viscous Cervical Environment-on-a-Chip for Selecting High-Quality Sperm from Human Semen

When ejaculated sperm travels through the vagina to the uterus, mucus secreted by the cervical canal generally filters out sperm having low motility and poor morphology. To investigate this selection principle in vivo, we developed a microfluidic sperm-sorting chip with a viscous medium (polyvinylpyrrolidone: PVP) to imitate the biophysical environment mimic system of the human cervical canal. The material property of the PVP solution was tuned to the range of viscosities of cervical mucus using micro-viscometry. The selection of high-quality human sperm was experimentally evaluated in vitro and theoretically analyzed by the convection-diffusion mechanism. The convection flow is shown to be dominant at low viscosity of the medium used in the sperm-sorting chip when seeded with raw semen; hence, the raw semen containing sperm and debris convectively flow together with suppressed relative dispersions. Also, it was observed that the sperm selected via the chip not only had high motilities but also normal morphologies and high DNA integrity. Therefore, the biomimetic sperm-sorting chip with PVP medium is expected to improve male fertility by enabling the selection of high-quality sperm as well as uncovering pathways and regulatory mechanisms involved in sperm transport through the female reproductive tract for egg fertilization.

Should rescue ICSI be re-evaluated considering the deferred transfer of cryopreserved embryos in in-vitro fertilization cycles? A systematic review and meta-analysis

BACKGROUND

Total fertilization failure represents a particularly frustrating condition for couples undergoing in vitro fertilization. With the aim of reducing the occurrence of total fertilization failure, intracytoplasmic sperm injection (ICSI) has become the first choice over conventional in vitro fertilization (IVF) procedures although evidence of improved results is still debated and its use in couples without male factor infertility is not recommended. Among the strategies potentially useful to promote the use of conventional IVF, we herein call attention to the late rescue ICSI, which consists in performing ICSI after 18-24 h from conventional insemination on oocytes that show no signs of fertilization. This treatment has however been reported to be associated with a low success rate until recent observations that embryos derived from late rescue ICSI may be transferred after cryopreservation in a frozen-thawed cycle with improved results. The aim of the present study was to assess whether frozen embryos deriving from rescue ICSI performed about 24 h after conventional IVF may represent a valuable option for couples experiencing fertilization failure.

METHODS

A systematic review on the efficacy of late rescue ICSI was performed consulting PUBMED and EMBASE.

RESULTS

Including twenty-two original studies, we showed that clinical pregnancy rate per embryo transfer and implantation rate obtainable with fresh embryo transfers after rescue ICSI are not satisfactory being equal to 10 and 5%, respectively. The transfer of cryopreserved rescue ICSI embryos seems to offer a substantial improvement of success rates, with pregnancy rate per embryo transfer and implantation rate equal to 36 and 18%, respectively. Coupling rescue ICSI with frozen embryo transfer may ameliorate the clinical pregnancy rate for embryo transfer with an Odds Ratio = 4.7 (95% CI:2.6-8.6).

CONCLUSION

Results of the present review support the idea that r-ICSI coupled with frozen embryo transfer may overcome most of the technical and biological issues associated with fresh transfer after late r-ICSI, thus possibly representing an efficient procedure for couples experiencing fertilization failure following conventional IVF cycles.

TRIAL REGISTRATION

Prospero registration ID: CRD42021239026 .

Effects of three pro-nuclei (3PN) incidence on laboratory and clinical outcomes after early rescue intracytoplasmic sperm injection (rescue-ICSI): an analysis of a 5-year period

OBJECTIVES

We aimed to explore the effect of three pro-nuclei (3PN) incidence on laboratory and clinical outcomes after early rescue intracytoplasmic sperm injection (rescue-ICSI).

METHODS

This study included 509 early rescue-ICSI cycles from February 2014 to February 2019. The patients were divided into 3PN = 0% (394 cycles) and 3PN > 0% (115 cycles) group. Main outcomes compared were good quality embryo, available embryo, implantation (IR), clinical pregnancy (CPR), abortion (AR) and live birth rates (LBR).

RESULTS

There were no significant differences in the basal characteristics between two groups (p > .05). We observed that 3PN = 0% and 3PN > 0% groups had similar good quality embryo (47.02 versus 46.80%; p = .917) and available embryo (83.28 versus 81.37%; p = .247) rates. Our results showed that the IR (47.26 versus 51.05%; p = .357), CPR (61.17 versus 66.08%; p = .338) and LBR (52.80 versus 50.43%; p = .656) were comparable between 3PN = 0% and 3PN > 0% groups. The 3PN = 0% group showed significantly lower AR than that in the 3PN > 0% group (11.20 versus 21.05%; p = .029; OR 2.114; 95% CI 1.069-4.178).

CONCLUSIONS

3PN incidence made negative effects on the clinical outcomes after early rescue-ICSI.

Conventional IVF revisited: Is ICSI better for non-male factor infertility? Randomized controlled double blind study

STUDY QUESTION

Is ICSI better than conventional IVF for non-male factor infertility?

SUMMARY ANSWER

IVF should be the choice of assisted reproductive technique in non-male factor infertility cases.

WHAT IS ALREADY KNOWN

Although total fertilization failure is a major concern for patients and professionals, the overall risk/benefit analysis favors conventional IVF in non-male factor infertility cases. However, according to the ESHRE EIM database pertaining to 1997-2012, the use of IVF has been continuously decreasing in favor of ICSI.

STUDY DESIGN, SIZE, DURATION

Randomized controlled double-blind study involving 138 women undergoing ART in a private Center.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All couples with a female partner ≤42 years of age and without severe male factor (total progressive motile sperm with normal morphology >10.000) were included in the study. Exclusion criteria were: history of total fertilization failure, less than 6 cumulus oocyte complexes (COC) available for fertilization, prenatal genetic testing (PGT) cycles, unwillingness to participate and couples undergoing total cryopreservation for any indication. On the day of oocyte pick up, sibling COCs were randomly allocated to fertilization with IVF or denudation followed by ICSI to MII oocytes. The decision to transfer IVF or ICSI embryo(s) depended on embryo quality. Women receiving two embryos were given only IVF or ICSI embryos. Neither the clinician performing the transfer nor the patients were aware of the fertilization method used to generate the embryos transferred. Main outcome parameters were fertilization, clinical pregnancy, implantation and miscarriage rates.

MAIN RESULTS AND THE ROLE OF CHANCE

Demographic variables, ovarian reserve and infertility etiology, duration of stimulation, total gonadotropin consumption, peak estradiol levels were similar for IVF-ET and ICSI-ET groups. Mean number of COCs (18.95 vs 19.24), number of embryos transferred (1,81 vs 1,81), the ratio of good quality embryos/total embryos (56.89 % and 55.97 %), clinical pregnancy rates (63 % vs 49 %), implantation rates (31 % vs 28 %), and abortion rates (12,5 % vs 8,1 %) were also similar. A total of 1306 COCs were allocated for IVF while 1331 COCs were denuded for ICSI. Fertilization rate per inseminated oocyte was significantly higher in ICSI group (56,20 % vs 63,78 %). There were ten cases of total fertilization failure, all in the IVF group. Although overall fertilization rate was higher for ICSI, it was similar in both groups when cases with total fertilization failure were excluded.

LIMITATIONS, REASONS FOR CAUTION

The non-availability of live birth rates is a limitation. Randomization of sibling oocytes, not patients requires careful interpretation of pregnancy and implantation rates.

WIDER IMPLICATIONS OF THE FINDINGS

Lower cost, ease of application and similar clinical outcome makes IVF the choice of fertilization method in non-male factor infertility cases.

Perinatal and neonatal outcomes of pregnancies after early rescue intracytoplasmic sperm injection in women with primary infertility compared with conventional intracytoplasmic sperm injection: a retrospective 6-year study

Background

Early rescue intracytoplasmic sperm injection (ICSI) has been used in clinic as appropriate currently. While the outcomes of children born after this method were not well assessed. The purpose of this study was to evaluate the effect of early rescue ICSI on women with primary infertility.

Methods

Fresh embryo transfer cycles after rescue (n = 214) and conventional (n = 546) ICSI were retrospectively evaluated from women with primary infertility who underwent their first assisted reproductive technology cycles at our center in 2012–2017. The conventional ICSI group was subdivided into ICSI-1 (semen suitable for in vitro fertilization, IVF) and ICSI-2 (poor semen quality) to minimize bias from differences in semen quality. Pregnancy, delivery and neonatal outcomes were compared between groups.

Results

There was a higher rate of polyspermy and a lower rate of top-quality embryos (TQE) on day 3 for oocytes subject to rescue ICSI compared with conventional ICSI. This reduced the total number of TQE and the number of TQE transferred in the rescue ICSI group. There was no significant difference between groups in clinical pregnancy, ongoing pregnancy, early miscarriage and live birth. For pregnant women, gestational age, route of delivery, risk of preterm birth and gestational diabetes mellitus were also comparable. Neonatal outcomes including sex ratio, birth weight, neonatal intensive care unit admission and birth defects were also similar after rescue and conventional ICSI. Moreover, no differences were observed with the different ICSI subgroups.

Conclusions

For women with primary infertility who have a high risk of IVF fertilization failure (FF), rescue ICSI provides a safe and efficient alternative to minimize FF after initial IVF, but results in fewer TQE on day 3.

First birth following assisted sperm fusion insemination using sperm bound to zona pellucida

PURPOSE

To report a live birth after transfer of a vitrified-warmed blastocyst produced by assisted sperm fusion insemination (ASFI).

METHODS

Oocyte retrieval and in vitro fertilization (IVF) were performed on a 37-year-old woman. Six hours after IVF, an oocyte exhibited a single polar body and so was defined as an unfertilized oocyte. A motile sperm was collected from the zona pellucida of the unfertilized oocyte by an injection needle. The motile sperm was pressed onto the membrane of the unfertilized oocyte.

RESULTS

Two oocytes were matured and subjected to IVF. One of the 2 oocytes exhibited only one polar body and was defined as an unfertilized oocyte at 6 h after IVF; this oocyte then was subjected to ASFI. Two pronuclei were observed on the next day and cultured to the blastocyst stage. This embryo achieved blastocyst status and was vitrified on day 5. The resulting vitrified-warmed blastocyst was transferred, resulting in pregnancy and subsequent delivery of a healthy boy.

CONCLUSION

This report describes the first case of a successful birth following transfer of a vitrified-warmed blastocyst produced by ASFI.

Statistical Modelling Outcome of In Vitro Fertilization and Intracytoplasmic Sperm Injection: A Single Centre Study

BACKGROUND

Assisted reproductive techniques (ART) have been extensively used to treat infertility. Inaccurate prediction of a couple's fertility often leads to lowered self-esteem for patients seeking ART treatment and causes fertility distress.

OBJECTIVE

This prospective study aimed to statistically analyze patient data from a single reproductive medical center over a period of 18 months, and to establish mathematical models that might facilitate accurate prediction of successful pregnancy when ART are used.

METHODS

In the present study, we analyzed clinical data prospectively collected from 760 infertile patients visiting the second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University between June 1, 2016 and December 31, 2017. Various advanced statistical methods, including broken-line regression, were employed to analyze the data.

RESULTS

Age remained the most important factor affecting the outcome of IVF/ICSI. Using the broken-line regression model, the fastest clinical pregnancy declining age was between 25 and 32. Female infertility type was found to be a key predictor for the number of good-quality embryos and successful pregnancy, along with the antral follicle count (AFC), total number of embryos, recombinant follicle stimulating hormones (rFSH) dosage, estradiol (E2) on the trigger day, and total number of oocytes retrieved. rFSH dosage was also significantly associated with the number of oocytes retrieved and the number of frozen embryos.

CONCLUSION

The fastest clinical pregnancy declining age is ranged between 25 and 32, and female infertility type is evidenced as another key predictive factor for the cumulative outcome of ART.

The management of unexplained infertility: an evidence-based guideline from the Canadian Fertility and Andrology Society

Unexplained infertility is a common diagnosis affecting as many as 50% of couples seeking infertility care. As a diagnosis of exclusion, its treatment remains largely empirical. Historically, a step-wise progression in treatment has been initiated with the least invasive, least expensive option followed by a gradual progression to therapies using assisted reproductive technology. In recent years there have been advocates for more rapid-progression IVF. This guideline from the Canadian Fertility and Andrology Society (CFAS) provides comprehensive, evidence-based recommendations for the treatment of unexplained infertility, including expectant management, laparoscopy, intrauterine insemination (IUI) alone, ovarian stimulation with oral agents or gonadotropins alone, ovarian stimulation + IUI, and IVF. The quality of supporting evidence for each recommendation is evaluated using the framework outlined by the Canadian Task Force on Preventive Health Care. This guideline recognizes that the therapeutic approach should be individualized taking into account patient age and duration of infertility, and emphasizes those strategies that are most likely to result in a healthy live birth.

Mutational analysis of IZUMO1R in women with fertilization failure and polyspermy after in vitro fertilization

PURPOSE

The etiology of fertilization failure and polyspermy during assisted reproductive technology (ART) remains elusive. The aim of this study was to determine whether mutations in the IZUMO1 receptor (IZUMO1R) gene, which is essential for mammalian fertilization, contribute to the pathogenesis of fertilization failure or polyspermy in humans.

METHODS

We recruited 215 female subjects with fertilization failure/poor fertilization, 330 females with polyspermy, and 300 matched controls. All subjects underwent IVF treatment. Peripheral blood DNA of cases was extracted and screened for mutations in IZUMO1R gene.

RESULTS

Four rare single nucleotide polymorphisms (SNPs) of the IZUMO1R were identified among specimens from patients with fertilization failure and polyspermy but were absent in the 300 control subjects. These included a missense SNP (rs76779571 in exon 4), which was found in two fertilization failure patients, and a nonsynonymous SNP (rs61742524 in exon 1) and two synonymous SNPs (rs76781645 in exon 1 and rs377369966 in intron 2), which were found among three polyspermy cases.

CONCLUSIONS

The variations in IZUMO1R might play a role in the pathogenesis of fertilization failure and polyspermy, and the putative functions and effects of these rare variants require further studies.

Effect of normal sperm morphology rate (NSMR) on clinical outcomes for rescue-ICSI(R-ICSI) patients

PURPOSE

To investigate whether the normal sperm morphology rate (NSMR) can affect the clinical outcomes of rescue-ICSI(R-ICSI) patients.

METHODS

Based on different NSMR, the patients were divided into two groups as follows: NSMR < 4% and NSMR ≥ 4% group. Main outcomes compared were fertilization, cleavage, normal fertilization, high-quality embryo, transferrable embryo, no transferrable embryo cycles, implantation, clinical pregnancy and abortion rate. Some men's and women's basic parameters were compared between pregnancy and non-pregnancy group.

RESULTS

The basic parameter such as female age, endometrial thickness, infertility duration, Gn administration, Gn days, basal serum FSH and basal serum E2 found no significant difference between NSMR < 4% and NSMR ≥ 4% group (p > 0.05). There was no significant difference in aspects of the number of retrieved oocytes, the number of transferred embryos, fertilization, cleavage, normal fertilization, high-quality embryo, transferrable embryo, no transferred embryo cycle, implantation, clinical pregnancy and abortion rate between two groups (p > 0.05). Between pregnancy and non-pregnancy group, we observed no significant difference in the female age, the number of retrieved oocytes, the number of high-quality embryo, the number of transferrable embryos, Gn administration, Gn does, endometrial thickness, infertility duration, basal serum FSH, basal serum E2, sperm concentration and progressively motile sperm (p > 0.05).

CONCLUSIONS

Teratospermia made no effect on clinical outcomes of rescue-ICSI(R-ICSI) patients.

Strategies to improve fertilisation rates with assisted conception: a systematic review

Successful fertilisation is one of the key steps determining success of assisted conception. Various factors including sperm or oocyte pathology and environmental factors have a significant impact on fertilisation rates. This systematic review is aimed to evaluate the existing evidence about factors affecting fertilisation and strategies to improve fertilisation rates. A literature search was performed using Ovid MEDLINE ® (Jan 1950-April 2016), EMBASE (Jan 1950-April 2016), Ovid OLDMEDLINE ®, Pre-MEDLINE (Jan 1950-April 2016) and the Cochrane Library. Relevant key words were used to combine sets of results and a total 243 papers were screened. Only qualitative analysis was performed, as there was major heterogeneity in study design and methodology for quantitative synthesis. Factors affecting fertilisation were divided into sperm- and oocyte-related factors. The methods to improve fertilisation rates were grouped together based on the approach used to improve fertilisation rates. Optimising laboratory condition and procedural effects in techniques is associated with improved fertilisation rates. Various techniques are described to improve fertilisation rates including assisted oocyte activation, physiological intracytoplasmic sperm injection (PICSI) and intracytoplasmic morphologically selected sperm injection (IMSI). This review highlights the promising strategies under research to enhance fertilisation rates. Adequately powered multicentre randomised trials are required to evaluate these techniques before considering clinical application.

Oocyte Activation and Fertilisation: Crucial Contributors from the Sperm and Oocyte

This chapter intends to summarise the importance of sperm- and oocyte-derived factors in the processes of sperm-oocyte binding and oocyte activation. First, we describe the initial interaction between sperm and the zona pellucida, with particular regard to acrosome exocytosis. We then describe how sperm and oocyte membranes fuse, with special reference to the discovery of the sperm protein IZUMO1 and its interaction with the oocyte membrane receptor JUNO. We then focus specifically upon oocyte activation, the fundamental process by which the oocyte is alleviated from metaphase II arrest by a sperm-soluble factor. The identity of this sperm factor has been the source of much debate recently, although mounting evidence, from several different laboratories, provides strong support for phospholipase C ζ (PLCζ), a sperm-specific phospholipase. Herein, we discuss the evidence in support of PLCζ and evaluate the potential role of other candidate proteins, such as post-acrosomal WW-binding domain protein (PAWP/WBP2NL). Since the cascade of downstream events triggered by the sperm-borne oocyte activation factor heavily relies upon specialised cellular machinery within the oocyte, we also discuss the critical role of oocyte-borne factors, such as the inositol trisphosphate receptor (IP₃R), protein kinase C (PKC), store-operated calcium entry (SOCE) and calcium/calmodulin-dependent protein kinase II (CaMKII), during the process of oocyte activation. In order to place the implications of these various factors and processes into a clinical context, we proceed to describe their potential association with oocyte activation failure and discuss how clinical techniques such as the in vitro maturation of oocytes may affect oocyte activation ability. Finally, we contemplate the role of artificial oocyte activating agents in the clinical rescue of oocyte activation deficiency and discuss options for more endogenous alternatives.

Should metaphase 1 and 2 stages oocytes be vitrified in the same time for fertility preservation?

Aims: Could metaphase 1 (M1) and 2 (M2) stages oocytes from in vitro maturation (IVM) cycles and controlled-ovarian hyperstimulation (COH) cycles be frozen at the same time without any adverse effect of vitrification on further survival (SR) and maturation rates (MR)? Materials & methods: M1 from cancer patients were prospectively included in IVM/COH groups, and in study or control subgroups if they were vitrified or not. In each study subgroup, SR were compared with that of M2 oocytes vitrified/warmed from egg donors. MR were compared with those of fresh-M1 oocytes from control IVM/COH subgroups. Results: SR were not different between groups. MR compared respectively between survived- and fresh-M1 oocytes were similar when resulting from COH (85.2 vs 81.1%) but significantly lower after IVM (39.1 vs 73.3%). Conclusion: Simultaneous freezing of M1/M2 oocytes could be applied to COH but not to IVM during the course of fertility preservation.

Delayed intracytoplasmic sperm injection (ICSI) with trophectoderm biopsy and preimplantation genetic screening (PGS) show increased aneuploidy rates but can lead to live births with single thawed euploid embryo transfer (STEET)

PURPOSE

The aim of this study was to report the results of IVF with trophectoderm biopsy and preimplantation genetic screening (PGS) following delayed intracytoplasmic sperm injection (ICSI).

METHODS

Patients undergoing IVF with PGS and delayed ICSI were included in the study. Indications for delayed ICSI included absent or poor fertilization via standard insemination or more than 50 % immature oocytes, noted post-cumulus stripping for standard ICSI procedure. Delayed ICSI was performed the day after retrieval due to absent or poor fertilization. The immature oocytes were kept in extended culture, and if demonstrated maturity, ICSI was performed. Primary outcome included fertilization rate and blastocyst stage formation, defined by the number of blastocysts for biopsy. Secondary outcome included aneuploidy rate and pregnancy outcomes following single thawed euploid embryo transfers (STEET).

RESULTS

Sixteen patients with delayed ICSI were included in the study. Twelve were due to poor fertilization and four secondary to immature oocytes. A total of 219 oocytes were retrieved; ten were frozen upon patient request, 168 had standard insemination, and 13 had routine ICSI on the day of retrieval. A total of 129 oocytes underwent delayed ICSI. Sixty-three (49 %) fertilized, 19 (14.7 %) reached blastocysts for biopsy; fivw of which were chromosomally normal (26.3 %). Three patients underwent STEET of a delayed ICSI embryo; all three resulted in live births, including one embryo biopsied on day 8 of development.

CONCLUSION

Fertilization failure or an excessive proportion of immature oocytes in an IVF cycle, necessitating delayed ICSI, showed equivalent fertilization and blast formation rates. With the implementation of trophectoderm biopsy and PGS, these embryos can lead to healthy live born babies.

Cortical mechanics and myosin-II abnormalities associated with post-ovulatory aging: implications for functional defects in aged eggs

STUDY HYPOTHESIS

Cellular aging of the egg following ovulation, also known as post-ovulatory aging, is associated with aberrant cortical mechanics and actomyosin cytoskeleton functions.

STUDY FINDING

Post-ovulatory aging is associated with dysfunction of non-muscle myosin-II, and pharmacologically induced myosin-II dysfunction produces some of the same deficiencies observed in aged eggs.

WHAT IS KNOWN ALREADY

Reproductive success is reduced with delayed fertilization and when copulation or insemination occurs at increased times after ovulation. Post-ovulatory aged eggs have several abnormalities in the plasma membrane and cortex, including reduced egg membrane receptivity to sperm, aberrant sperm-induced cortical remodeling and formation of fertilization cones at the site of sperm entry, and reduced ability to establish a membrane block to prevent polyspermic fertilization.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

Ovulated mouse eggs were collected at 21-22 h post-human chorionic gonadotrophin (hCG) (aged eggs) or at 13-14 h post-hCG (young eggs), or young eggs were treated with the myosin light chain kinase (MLCK) inhibitor ML-7, to test the hypothesis that disruption of myosin-II function could mimic some of the effects of post-ovulatory aging. Eggs were subjected to various analyses. Cytoskeletal proteins in eggs and parthenogenesis were assessed using fluorescence microscopy, with further analysis of cytoskeletal proteins in immunoblotting experiments. Cortical tension was measured through micropipette aspiration assays. Egg membrane receptivity to sperm was assessed in in vitro fertilization (IVF) assays. Membrane topography was examined by low-vacuum scanning electron microscopy (SEM).

MAIN RESULTS AND THE ROLE OF CHANCE

Aged eggs have decreased levels and abnormal localizations of phosphorylated myosin-II regulatory light chain (pMRLC; P = 0.0062). Cortical tension, which is mediated in part by myosin-II, is reduced in aged mouse eggs when compared with young eggs, by ∼40% in the cortical region where the metaphase II spindle is sequestered and by ∼50% in the domain to which sperm bind and fuse (P < 0.0001). Aging-associated parthenogenesis is partly rescued by treating eggs with a zinc ionophore (P = 0.003), as is parthenogenesis induced by inhibition of mitogen-activated kinase (MAPK) 3/1 [also known as extracellular signal-regulated kinase (ERK)1/2] or MLCK. Inhibition of MLCK with ML-7 also results in effects that mimic those of post-ovulatory aging: fertilized ML-7-treated eggs show both impaired fertilization and increased extents of polyspermy, and ML-7-treated young eggs have several membrane abnormalities that are shared by post-ovulatory aged eggs.

LIMITATIONS, REASONS FOR CAUTION

These studies were done with mouse oocytes, and it remains to be fully determined how these findings from mouse oocytes would compare with other species. For studies using methods not amenable to analysis of large sample sizes and data are limited to what images one can capture (e.g. SEM), data should be interpreted conservatively.

WIDER IMPLICATIONS OF THE FINDINGS

These data provide insights into causes of reproductive failures at later post-copulatory times.

LARGE SCALE DATA

Not applicable.

STUDY FUNDING AND COMPETING INTERESTS

This project was supported by R01 HD037696 and R01 HD045671 from the NIH to J.P.E. Cortical tension studies were supported by R01 GM66817 to D.N.R. The authors declare there are no financial conflicts of interest.

Determining the need for rescue intracytoplasmic sperm injection in partial fertilisation failure during a conventional IVF cycle

To explore the need for rescue intracytoplasmic sperm injection (ICSI) in cases of partial fertilisation failure during a conventional in vitro fertilisation cycle, rescue ICSI was performed for cycles with a fertilisation rate of <50%. The data were divided into three groups based on the fertilisation rate: group 1 (0%), group 2 (<25%) and group 3 (>25%). The impact of rescue ICSI on each group was then analysed in terms of ovum fertilisation, embryo development, embryo utilisation and selection of embryos for transfer. Rescue ICSI was performed on 1831 unfertilised oocytes from 313 cycles. The fertilisation rates for group 1, group 2 and group 3 were 74.66, 68.35 and 65.46%, and the rate of polyploidy in the three groups was 8.55, 11.33, and 14.47%. The percentage of embryos that can be transferred from rescue ICSI for group 2 was 38.33%, and this value was higher than those of the other two groups. It is concluded that rescue ICSI is not recommended for patients with an IVF rate of >25% as the procedure is associated with a greater risk and low returns. However, it is feasible to perform rescue ICSI for patients with IVF rates of <25%.

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging

PURPOSE

Childbearing delay contributes to the increase of subfertile couples that require assisted reproductive technology (ART). Subfertility relates with reproductive aging (RA). In vitro aging (IvA) (due to extended culture) may also impair oocyte competence. Aims of this study were to evaluate and compare the oocyte ultrastructure after RA and IvA.

METHODS

Cumulus-oocyte complexes (COCs) (n = 68), with metaphase II oocyte and expanded cumulus, from consenting patients (<35 years old and ≥35 years old, n = 36), were selected by phase contrast microscopy and fixed at pick up, or after 24 h culture. COCs (n = 44) were studied by light and qualitative/morphometric transmission electron microscopy. Two-way ANOVA, with age and culture as grouping factors, was applied for statistical analysis (p < 0.05). Metaphase II cumulus-free oocytes (n = 24) were selected for confocal microscopy observations.

RESULTS

Significant decrease of mitochondria-smooth endoplasmic reticulum aggregates, increase of mitochondria-vesicle complexes size and amount, decrease of cortical granules and microvilli, and alterations of the spindle structure characterized both RA and IvA oocytes. These changes were significantly more evident in the RA oocytes submitted to IvA. RA oocytes also showed changes of the zona pellucida and occurrence of vacuoles after culture. Cumuli appeared re-compacted after culture, irrespective of the age of the patients.

CONCLUSIONS

These data demonstrated that aging is related to decay of oocyte ultrastructural quality, and that oocytes from elder women are more sensitive to prolonged culture (IvA) than the oocytes from younger women. These morphological results should be considered when applying ART in aged patients, rescue ICSI, or artificial oocyte activation.

Association between etiologic factors in infertile couples and fertilization failure in conventional in vitro fertilization cycles

The aim of this study was to investigate the relationship between the etiology of the couples and risk of fertilization failure (FF) in conventional in vitro fertilization (IVF) cycles and the effect of rescue intracytoplasmic sperm injection (ICSI) technique to offspring. A total of 2542 IVF cycles were divided into four groups according to infertile etiology: Group A - primary infertility with normal semen parameters; Group B - secondary infertility with oligoasthenozoospermia; Group C - primary infertility with oligoasthenozoospermia; and Group D - secondary infertility with normal semen parameters. The results showed that there were significant differences in incidence of FF among Group A (16.8%), Group B (20.9%), Group C (48.7%), and Group D (0.9%) (p < 0.001). Logistic regression models demonstrated that primary infertility (OR: 10.898, 95% CI: 4.651-25.583, p < 0.001) and oligoasthenozoospermia (OR: 12.215, 95% CI: 5.903-25.276, p < 0.001) were independent risk factors for FF. There were no significant differences in main outcomes between conventional ICSI and rescue ICSI. In conclusion, the patients with primary infertility and oligoasthenozoospermia might be at higher risk of FF. The rescue ICSI technique is safe and helpful for IVF cycles of FF.

Total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta are significantly correlated with fertilization rates after intracytoplasmic sperm injection

OBJECTIVE

To study the relationship of total levels, localization patterns, and proportions of sperm exhibiting phospholipase C zeta, with fertilization rates after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

DESIGN

Laboratory study; controls vs. patients after IVF (n = 27) or ICSI (n = 17) treatment.

SETTING

Fertility center.

PATIENT(S)

A total of 44 semen samples, subjected to either IVF or ICSI treatment. Oocyte collection, ICSI or IVF, determination of sperm concentration and motility, and immunocytochemical analyses of phospholipase C zeta (PLCζ).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Percentages of sperm exhibiting PLCζ.

RESULT(S)

Significant positive correlation between ICSI fertilization rates and total levels, localization patterns, and the proportion (percentage) of sperm exhibiting PLCζ. Total levels, localization patterns, and the proportion of sperm exhibiting PLCζ are correlated with fertilization rates for ICSI, but not for IVF.

CONCLUSION(S)

Evaluating total levels, localization patterns, and proportions of PLCζ may represent a useful diagnostic tool for clinical purposes in men for whom IVF is not advised or has previously failed. This clinical study further supports the fundamental role of PLCζ in the oocyte activation process.

Successful live birth after transfer of blastocyst and frozen blastocyst from rescue ICSI with application of polarized light microscopy for spindle examination on unfertilized eggs

This article aims to report successful live births after transfer of fresh blastocyst or vitrified/warmed blastocyst derived from intracytoplasmic sperm injection (ICSI) on day-1 of unfertilized mature eggs (so-called “rescue ICSI”) with spindle examination using polarized light microscopy. Two couples who had rescue ICSI performed achieved a positive pregnancy result after the transfer of a fresh or vitrified blastocyst. The two pregnancies led to the live births of a healthy baby boy of 2.72 kg and baby girl of 3.4 kg, respectively.

Association of assisted reproductive technology (ART) treatment and parental infertility diagnosis with autism in ART-conceived children

STUDY QUESTION

Are assisted reproductive technology (ART) treatment factors or infertility diagnoses associated with autism among ART-conceived children?

SUMMARY ANSWER

Our study suggests that the incidence of autism diagnosis in ART-conceived children during the first 5 years of life was higher when intracytoplasmic sperm injection (ICSI) was used compared with conventional IVF, and lower when parents had unexplained infertility (among singletons) or tubal factor infertility (among multiples) compared with other types of infertility.

WHAT IS KNOWN ALREADY

Some studies found an increased risk of autism among ART-conceived infants compared with spontaneously-conceived infants. However, few studies, and none in the USA, have examined the associations between types of ART procedures and parental infertility diagnoses with autism among ART-conceived children.

STUDY DESIGN, SIZE, DURATION

Population-based retrospective cohort study using linkages between National ART Surveillance System (NASS) data for 1996-2006, California Birth Certificate data for 1997-2006, and California Department of Developmental Services (DDS) Autism Caseload data for 1997-2011.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All live born ART-conceived infants born in California in 1997-2006 (n = 42 383) with 5-year observation period were included in the study. We assessed the annual incidence of autism diagnosis documented in DDS, which includes information on the vast majority of persons with autism in California, and the association of autism diagnosis with ART treatment factors and infertility diagnoses.

MAIN RESULTS AND THE ROLE OF CHANCE

Among ART-conceived singletons born in California between 1997 and 2006, the incidence of autism diagnosis remained at ∼0.8% (P for trend 0.19) and was lower with parental diagnosis of unexplained infertility (adjusted hazard risk ratio [aHRR]; 95% confidence interval: 0.38; 0.15-0.94) and higher when ICSI was used (aHRR 1.65; 1.08-2.52), when compared with cases without these patient and treatment characteristics. Among ART-conceived multiples, the incidence of autism diagnosis between 1997 and 2006 remained at ∼1.2% (P for trend 0.93) and was lower with parental diagnosis of tubal factor infertility (aHRR 0.56; 0.35-0.90) and higher when ICSI was used (aHRR 1.71; 1.10-2.66).

LIMITATIONS, REASONS FOR CAUTION

Study limitations include imperfect data linkages, lack of data on embryo quality and possible underestimation of autism diagnosis cases. Limitations of the observational study design could affect the analysis by the possibility of residual confounders. Since information about ICSI use was missing for most frozen/thawed embryo transfer cycles, our findings of association of ICSI use and autism diagnosis can only be generalizable to fresh embryo transfer cycles.

WIDER IMPLICATIONS OF THE FINDINGS

Our study provides additional evidence of the association between some types of ART procedures with autism diagnosis. Additional research is required to explain the increased risk of autism diagnosis with ICSI use, as well as studies on the effectiveness and safety of ICSI.

Trends in use of and reproductive outcomes associated with intracytoplasmic sperm injection

IMPORTANCE

Intracytoplasmic sperm injection (ICSI) is increasingly used in patients without severe male factor infertility without clear evidence of a benefit over conventional in vitro fertilization (IVF).

OBJECTIVE

To assess national trends and reproductive outcomes for fresh IVF cycles (embryos transferred without being frozen) following the use of ICSI compared with conventional IVF with respect to clinical indications for ICSI use.

DESIGN, SETTING, AND POPULATION

Retrospective cohort study using data on fresh IVF and ICSI cycles reported to the US National Assisted Reproductive Technology Surveillance System during 1996-2012.

MAIN OUTCOMES AND MEASURES

Trends in ICSI use during 1996-2012 with respect to male factor infertility, unexplained infertility, maternal age 38 years or older, low oocyte yield, and 2 or more prior assisted reproductive technology cycles; reproductive outcomes for conventional IVF and ICSI cycles during 2008-2012, stratified by the presence or absence of male factor infertility.

RESULTS

Of the 1,395,634 fresh IVF cycles from 1996 through 2012, 908,767 (65.1%) used ICSI and 499,135 (35.8%) reported male factor infertility. Among cycles with male factor infertility, ICSI use increased from 76.3% (10,876/14,259) to 93.3% (32,191/34,506) (P < .001) during 1996-2012; for those without male factor infertility, ICSI use increased from 15.4% (4197/27,191) to 66.9% (42,321/63,250) (P < .001). During 2008-2012, male factor infertility was reported for 35.7% (176,911/494,907) of fresh cycles. Among those cycles, ICSI use was associated with a lower multiple birth rate compared with conventional IVF (30.9% vs 34.2%; adjusted relative risk [RR], 0.87; 95% CI, 0.83-0.91). Among cycles without male factor infertility (n = 317,996), ICSI use was associated with lower rates of implantation (23.0% vs 25.2%; adjusted RR, 0.93; 95% CI, 0.91-0.95), live birth (36.5% vs 39.2%; adjusted RR, 0.95; 95% CI, 0.93-0.97), and multiple live birth (30.1% vs 31.0%; adjusted RR, 0.93; 95% CI, 0.91-0.95) vs conventional IVF.

CONCLUSIONS AND RELEVANCE

Among fresh IVF cycles in the United States, ICSI use increased from 36.4% in 1996 to 76.2% in 2012, with the largest relative increase among cycles without male factor infertility. Compared with conventional IVF, ICSI use was not associated with improved postfertilization reproductive outcomes, irrespective of male factor infertility diagnosis.