Timing of Testicular Biopsy in Relation to Oocyte Retrieval and the Outcomes of Intracytoplasmic Sperm Injection

PURPOSE

We evaluate microscopic (micro) testicular sperm extraction (TESE) timing relative to oocyte retrieval on intracytoplasmic sperm injection outcome.

MATERIALS AND METHODS

Couples with nonobstructive azoospermia who underwent intracytoplasmic sperm injection with freshly retrieved spermatozoa were analyzed based on whether micro-TESE was performed at least 1 day prior to oocyte retrieval (TESE-day-before group) or on the day of oocyte retrieval (TESE-day-of group). Embryology and clinical outcomes were compared.

RESULTS

The percentage of patients who underwent a successful testicular sperm retrieval was significantly lower in the TESE-day-before cohort (62%) than in the TESE-day-of cohort (69%; odds ratio [OR] 1.4, 95% CI [1.1, 1.7], P < .001). The fertilization rate was also found to be significantly lower in the TESE-day-before group (45%) than in the TESE-day-of group (53%; OR 1.4, 95% CI [1.2, 1.7], P = .01). Although the association between the cleavage rate and TESE timing was not statistically significant, the implantation rate was found to be significantly higher in the day-before cohort (28%) than in the day-of cohort (22%; OR 0.7, 95% CI [0.6, 0.9], P = .01). Nevertheless, it was found that the clinical pregnancy and delivery rates were not statistically significantly associated with the TESE timing.

CONCLUSIONS

Although sperm retrieval and fertilization rates were lower in the TESE-day-before cohort, the 2 cohorts showed comparable embryologic and clinical outcomes. Micro-TESE can be performed before oocyte harvesting to provide physicians ample time to decide between cancelling oocyte retrieval or retrieving oocytes for cryopreservation.

Genetic profiling of azoospermic men to identify the etiology and predict reproductive potential

PURPOSE

To identify germline mutations related to azoospermia etiology and reproductive potential of surgically retrieved spermatozoa, and to investigate the feasibility of predicting seminiferous tubule function of nonobstructive azoospermic men by transcriptomic profiling of ejaculates.

MATERIALS AND METHODS

Sperm specimens were obtained from 30 men (38.4 ± 6 years) undergoing epididymal sperm aspiration for obstructive azoospermia (OA, n = 19) acquired by vasectomy, or testicular biopsy for nonobstructive azoospermia (NOA, n = 11). To evaluate for a correlation with azoospermia etiology, DNAseq was performed on surgically retrieved spermatozoa, and cell-free RNAseq on seminal fluid (n = 23) was performed to predict spermatogenesis in the seminiferous tubule.

RESULTS

Overall, surgically retrieved sperm aneuploidy rates were 1.7% and 1.8% among OA and NOA cohorts, respectively. OA men carried housekeeping-related gene mutations, while NOA men displayed mutations on genes involved in crucial spermiogenic functions (AP1S2, AP1G2, APOE). We categorized couples within each cohort according to ICSI clinical outcomes to investigate genetic causes that may affect reproductive potential. All OA-fertile men (n = 9) carried mutations in ZNF749 (sperm production), whereas OA-infertile men (n = 10) harbored mutations in PRB1, which is essential for DNA replication. NOA-fertile men (n = 8) carried mutations in MPIG6B (stem cell lineage differentiation), whereas NOA-infertile individuals (n = 3) harbored mutations in genes involved in spermato/spermio-genesis (ADAM29, SPATA31E1, MAK, POLG, IFT43, ATG9B) and early embryonic development (MBD5, CCAR1, PMEPA1, POLK, REC8, REPIN1, MAPRE3, ARL4C). Transcriptomic assessment of cell-free RNAs in seminal fluid from NOA men allowed the prediction of residual spermatogenic foci.

CONCLUSIONS

Sperm genome profiling provides invaluable information on azoospermia etiology and identifies gene-related mechanistic links to reproductive performance. Moreover, RNAseq assessment of seminal fluid from NOA men can help predict sperm retrieval during testicular biopsies.

Successful cryptozoospermia management with multiple semen specimen collection

OBJECTIVE

To determine the prevalence of sperm suitable for intracytoplasmic sperm injection (ICSI) in fresh ejaculated semen samples provided by men scheduled for a microdissection testicular sperm extraction (mTESE) procedure. Secondary objectives included an evaluation of the effect of a short abstinence period on semen quality and ICSI outcomes for men with cryptozoospermia.

DESIGN

Retrospective cohort study.

SETTING

Academic medical center.

PATIENTS

All men were scheduled to undergo a mTESE procedure by a single, high-volume surgeon at an academic center from September 1, 2015, to May 1, 2021.

INTERVENTION

Presence of sperm suitable for ICSI in the ejaculate on the day of scheduled mTESE.

MAIN OUTCOME MEASURES

Prevalence of sperm suitable for ICSI in the ejaculate among previously diagnosed men with azoospermia. Secondary outcomes included changes in semen parameters, clinical pregnancy rate, and live birth rate.

RESULTS

Of 727 planned mTESE procedures, 69 (9.5%) were canceled because sperm suitable for ICSI were identified in a fresh ejaculated sample produced on the day of scheduled surgery (typically one day before oocyte retrieval). Overall, 50 men (50/727, 6.9%) used these rare, ejaculated sperm for ICSI. Semen samples obtained with <24 hours of abstinence were more likely to have better motility than the sample initially provided on the day of the planned mTESE. The live birth rate per ICSI attempt using these rare, ejaculated sperm was 36% (19/53).

CONCLUSION

Providing a fresh ejaculated semen sample on the day of mTESE allows nearly 10% of men with azoospermia to avoid surgery with satisfactory ICSI outcomes. Providing multiple ejaculated samples over a short period of time does not adversely affect sperm concentration and may enhance sperm motility in men with cryptozoospermia.

Can a sperm selection technique improve embryo ploidy?

BACKGROUND

Spermatozoa with the highest motility retain a superior genomic integrity, and elevated sperm chromatin fragmentation (SCF) has been linked to a lower ability of the conceptus to develop and implant. Therefore, the utilization of a sperm selection method, such as microfluidic sperm selection (MFSS), is capable of reducing the SCF by yielding the most motile fraction of spermatozoa with the highest embryo developmental competence. What remains unclear, however, is the causal mechanism that links SCF to an impaired embryo development.

OBJECTIVES

To identify a relationship between SCF and an unexpectedly high proportion of embryo aneuploidy, while addressing treatment options.

MATERIALS AND METHODS

We identified couples with a high incidence of embryo aneuploidy in a previous intracytoplasmic sperm injection (ICSI) cycle with pre-implantation genetic testing for aneuploidy (PGT-A), utilizing spermatozoa selected by density gradient (DG). Terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) and neutral Comet assays were carried out on the semen specimens to assess total SCF and double-stranded DNA (dsDNA) fragmentation, respectively. These couples underwent subsequent ICSI/PGT-A cycles with MFSS. Total SCF and dsDNA fragmentation were compared between the two sperm selection methods. Embryo aneuploidy, implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between the couples' historical DG and subsequent MFSS cycles.

RESULTS

In 57 couples undergoing 71 ICSI/PGT-A cycles, where DG sperm selection was carried out, a high incidence of aneuploid embryos (74.7%) resulted in poor implantation and no viable pregnancies. Testing for SCF, inclusive of dsDNA breaks, evidenced a SCF of 26.2% and dsDNA break of 3.6% in the raw specimen, that decreased to 18.0% (p < 0.001) and 3.1%, respectively, in the DG processed specimen. Following MFSS, total SCF and dsDNA fragmentation decreased to 1.9% and 0.3%, respectively (p < 0.001). The embryo euploidy rate remarkable improved from 25.3% in the DG cycles to 42.9% in the MFSS cycles (p < 0.001). The 6.7% implantation rate in the DG cycles increased to 65.5% in the MFSS cycles (p < 0.001). Similarly, the clinical pregnancy rate rose from 10.5% (DG) to 64.6% (MFSS), resulting in a 62.5% delivery rate (p < 0.001).

DISCUSSION AND CONCLUSIONS

In couples with a relatively young female partner with a negative infertility workup, and a male partner with semen parameters adequate for ICSI, presenting with a high rate of embryo aneuploidy, an additional subtle male factor component may be the culprit. Thus, it is crucial to assess the SCF and test for the dsDNA breaks, which can eventually contribute to embryo chromosomal abnormalities. Given the inverse relationship between SCF and motility, a selection of the most motile gamete by MFSS enhanced the proportion of spermatozoa with an intact genome, contributing to the generation of more euploid embryos that are capable of implanting and yielding increased term pregnancies.

Sperm centriolar factors and genetic defects that can predict pregnancy

The human sperm centrosome, comprising the two morphologically distinct centrioles and associated pericentriolar materials, plays a crucial role in fertilization and early embryonic development after fertilization. Once inside the oocyte, the sperm centrosome serves as a microtubule-organizing center, orchestrating mitotic spindle formation, chromosome segregation, and syngamy. Abnormalities of the sperm centrosome can lead to abnormal embryonic development and embryonic chromosomal instability, and are associated with pregnancy loss. Recent research has shed light on the molecular composition, regulation, and function of this vital organelle. Understanding the intricacies of the sperm centrosome is crucial for elucidating the mechanisms underlying successful fertilization and early embryonic development, as well as addressing infertility and developmental disorders associated with centrosomal defects.

A novel approach toward the generation of oocytes by direct diploid cell haploidization

Oocyte-mediated somatic cell haploidization is a process in which a diploid cell halves its chromosomal content by segregating its homologue within the ooplasm. Replacing the donor oocyte nucleus with a patient's female diploid somatic nucleus can generate patient-genotyped oocytes. Insemination of these resulting constructs enables their activation and induces a reductive meiotic division, haploidizing the diploid female donor cell that can subsequently support syngamy with the male genome and create a zygote. So far, experimental data for this method have been limited and have not consistently proven the generation of chromosomally normal embryos. Overall, we achieved reconstruction of murine oocytes with a micromanipulation survival rate of 56.5%, and a correct haploidization and fertilization rate of 31.2%, resulting in a 12.7% blastocyst rate. Time-lapse analysis revealed that reconstructed embryos underwent a timely polar body extrusion and pronuclear appearance followed by a satisfactory embryonic cleavage, comparable with the control. Whole genome sequencing of the analyzed embryos indicated that 27.3% (6/22) were properly diploid. Our findings suggest that diploid cell haploidization may be a feasible technique for creating functional gametes in mammals.

Assisted gamete treatment to pinpoint acquired meiotic maturity and overcome oocyte activation deficiency contributed by both gametes

Objective

To treat couples with total fertilization failure (TFF) based on a combined oocyte- and sperm-related oocyte activation deficiency by optimizing oocyte response to chemical activation with calcium ionophore.

Design

Case report.

Setting

Tertiary Hospital.

Patients

Two couples with a history of TFF after intracytoplasmic sperm injection intracytoplasmic sperm injection (ICSI).

Interventions

To overcome oocyte-related oocyte activation deficiency (OAD), extended in vivo/in vitro oocyte maturation was performed to enhance ooplasmic maturity; to address sperm-related OAD, assisted gamete treatment (AGT) was performed to trigger oocyte activation.

Main outcome measures

Treatment cycle outcomes for the 2 couples undergoing ICSI with extended oocyte maturation (EOM) and AGT.

Results

We identified 2 couples with TFF after ICSI because of a combined factor of OAD confirmed by phospholipase C zeta expression and genomic assessment. Initial AGT treatment alone failed to enhance fertilization, suggesting superimposed oocyte dysmaturity prohibiting oocytes from responding to chemical stimuli. To address this complex form of OAD, in couple 1, 27 oocytes out of 34 retrieved presented normal metaphase II spindles after EOM; ICSI with AGT yielded a fertilization rate of 63.0% (17/27). All 17 zygotes were cryopreserved initially. Two embryos were thawed and transferred, yielding a monochorionic diamniotic twin pregnancy. Couple 2 underwent 3 ICSI cycles with EOM and AGT; 91.4% (32/35) of oocytes displayed normal metaphase II spindle and achieved an overall fertilization rate of 43.8% (14/32). A total of 12 blastocysts were cryopreserved. A single 46XY blastocyst was thawed and transferred, resulting in a singleton pregnancy.

Conclusions

Our study has demonstrated the usefulness of EOM by targeting spindle presence to enhance chemical responses to AGT.

Assessing male gamete genome integrity to ameliorate poor assisted reproductive technology clinical outcome

OBJECTIVE

To assess the role of evaluating sperm chromatin fragmentation (SCF) as a tool to guide treatment in couples who achieved unexpectedly poor clinical outcomes after intracytoplasmic sperm injection (ICSI).

DESIGN

We identified couples with an unexpectedly suboptimal clinical outcome after ICSI who were then screened for SCF. Consequently, the same couples were counseled to undergo a subsequent ICSI cycle using either ejaculates processed by microfluidic sperm selection (MFSS) or spermatozoa retrieved from the testis, and clinical outcomes were compared between history and treatment cycles. To confirm the sole effect of a compromised male gamete, we compared the ICSI outcome in cycles where male gametes with abnormal SCF were used to inseminate autologous and donor oocytes. Finally, to eliminate an eventual confounding female factor component, we compared the clinical outcome of ICSI cycles using sibling donor oocytes injected with spermatozoa with normal or abnormal SCF.

SETTING

Academic reproductive medicine center point of care.

PATIENT(S)

The patient population consisted of 76 couples with reproductively healthy and relatively young female partners and male partners with compromised semen parameters, but suitable for ICSI. In a subanalysis, we identified 67 couples with abnormal SCF who underwent ICSI cycle(s) with donor oocytes. Furthermore, we identified 29 couples, 12 with normal SCF and 17 with abnormal, uncorrected SCF, and 7 couples with abnormal, corrected SCF vs. a control, who used sibling donor oocytes for their ICSI cycle(s).

INTERVENTION(S)

For couples who resulted in surprisingly low clinical outcomes after ICSI, despite semen parameters adequate for ICSI and a normal female infertility evaluation, a SCF assessment was performed on the semen specimen using the terminal deoxynucleotidyl transferase-mediated fluorescein-deoxyuridine triphosphate nick-end labeling (TUNEL) assay. The couples then underwent a subsequent ICSI cycle with spermatozoa processed by MFSS or surgically retrieved. Moreover, cycles with donor oocytes were used to confirm the sole contribution of the male gamete.

MAIN OUTCOME MEASURE(S)

Clinical outcomes, such as fertilization, embryo implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between history and treatment cycle(s) using ejaculated spermatozoa selected by MFSS or from a testicular biopsy, taking into consideration the level of SCF. In a subanalysis, we reported the clinical outcomes of 67 patients who used donor oocytes and compared them with cycles where their own oocytes were used. Furthermore, we compared the ICSI clinical outcomes between cycles using sibling donor oocytes injected with low or high SCF with or without sperm intervention aimed at correcting, or alleviating the degree of SCF.

RESULT(S)

In a total of 168 cycles, 76 couples had in a prior cycle a 67.1% fertilization rate, and clinical pregnancy and pregnancy loss rates of 16.6% and 52.3%, respectively. After testing for SCF, the DNA fragmentation rate was 21.6%. This led to a subsequent ICSI cycle with MFSS or testicular sperm extraction, resulting in clinical pregnancy and delivery rates of 39.2%, and 37.3%, respectively. The embryo implantation rate increased to 23.5%, whereas the pregnancy loss rate decreased to 5% in the treatment cycle. This was particularly significant in the moderate SCF group, reaching embryo implantation, clinical pregnancy, and delivery rates of 24.3%, 40.4%, and 36.2%, respectively, and reducing the pregnancy loss rate to 10.5% in post-sperm treatment cycles. In 67 patients with high SCF who used donor oocytes, a significantly higher fertilization rate of 78.1% and embryo implantation rate of 29.1% were reported, compared with those in couples also with an elevated SCF who used their own. Interestingly, the clinical pregnancy and delivery rates only increased slightly from 28.0%-36.1% and from 23.7%-29.2%, respectively. To further control for a female factor, we observed couples who shared sibling donor oocytes, 17 with normal SCF and 12 with abnormal (uncorrected) SCF. Interestingly, the abnormal SCF group had impaired fertilization (69.3%), embryo implantation (15.0%), and delivery (15.4%) rates. For an additional 15 couples who split their donor oocytes, 8 had normal SCF, and although 7 couples originally had abnormal SCF, 4 used microfluidic processing, 2 used testicular spermatozoa, and 1 used donor spermatozoa to alleviate the degree of SCF, resulting in comparable clinical outcomes with the normal SCF group.

CONCLUSION(S)

A superimposed male factor component may explain the disappointing ICSI outcome in some couples despite reproductively healthy female partners. Therefore, it may be useful to screen couples for SCF to guide treatment options and maximize chances of a successful pregnancy. The improved, but suboptimal pregnancy and delivery outcomes observed in couples using donor oocytes confirmed the exclusive detrimental role that the male gamete exerted on embryo development despite the presence of putative oocyte repair mechanisms.

Profiling the male germline genome to unravel its reproductive potential

OBJECTIVE

To identify specific germline mutations related to sperm reproductive competence, in couples with unexplained infertility.

DESIGN

In this retrospective study, couples were divided according to whether they had successful intracytoplasmic sperm injection outcomes (fertile) or not (infertile). Ancillary sperm function tests were performed on ejaculates, and whole exome sequencing was performed on spermatozoal DNA. Sperm aneuploidy and gene mutation profiles were compared between the 2 cohorts as well as according to the specific reasons for reproductive failure.

SETTING

Center for reproductive medicine at a major academic medical center.

PATIENT(S)

Thirty-one couples with negative infertility workups and normal semen parameters.

INTERVENTION(S)

Couples with mutations on fertilization- or embryo development-related genes were subsequently treated by assisted gamete treatment or microfluidics, respectively.

MAIN OUTCOME MEASURE(S)

Intracytoplasmic sperm injection cycle outcomes including fertilization, clinical pregnancy, and delivery rates.

RESULT(S)

Sperm aneuploidy was lower in the fertile group (4.0% vs. 8.4%). Spermatozoa from both cohorts displayed mutations associated with sperm-egg fusion (ADAM3A) and acrosomal development (SPACA1), regardless of reproductive outcome. The infertile cohort was then categorized according to the reasons for reproductive failure: absent fertilization, poor early embryo development, implantation failure, or pregnancy loss. Spermatozoa from the fertilization failure subgroup (n = 4) had negligible PLCζ presence (10% ± 9%) and gene mutations (PLCZ1, PIWIL1, ADAM15) indicating a sperm-related oocyte-activating deficiency. These couples were successfully treated by assisted gamete treatment in their subsequent cycles. Spermatozoa from the poor early embryo development subgroup (n = 5) had abnormal centrosomes (45.9% ± 5%), and displayed mutations impacting centrosome integrity (HAUS1) and spindle/microtubular stabilization (KIF4A, XRN1). Microfluidic sperm processing subsequently yielded a term pregnancy. Spermatozoa from the implantation failure subgroup (n = 7) also had abnormal centrosomes (53.1% ± 13%) and carried mutations affecting embryonic implantation (IL9R) and microtubule and centrosomal integrity (MAP1S, SUPT5H, PLK4), whereas those from the pregnancy loss subgroup (n = 5) displayed mutations on genes involved in trophoblast development (NLRP7), cell cycle regulation (MARK4, TRIP13, DAB2IP, KIF1C), and recurrent miscarriage (TP53).

CONCLUSION(S)

By assessing the sperm genome, we identified specific germline mutations related to various reproductive processes. This information may clarify elusive factors underlying reproductive competence and enhance treatment for couples with unexplained infertility.

A comparison between the Felix™ electrophoretic system of sperm isolation and conventional density gradient centrifugation: a multicentre analysis

PURPOSE

Developing optimized techniques for the isolation of human spermatozoa possessing low levels of DNA damage is an important objective for the ART industry. The purpose of this study was to compare a novel electrophoretic system (Felix™) of sperm isolation with a conventional method involving density gradient centrifugation (DGC).

METHODS

Five international ART Centres in Australia, India, Sweden, the USA, and China have collaborated in order to compare the quality of the sperm populations isolated by Felix™ and DGC in terms of processing time, sperm concentration, motility, vitality, and DNA integrity as assessed by 3 methods: SCSA, Halo, and TUNEL.

RESULTS

Across all centers, 112 comparisons were performed. Although significant differences were noted between centers in terms of the quality of the semen samples subjected for analysis, overall, both methods were equally capable of isolating populations of spermatozoa exhibiting high levels of vitality and progressive motility. The absolute numbers of spermatozoa recovered were significantly (p < 0.001) lower with the Felix™ device although sperm quality was higher with 4/5 centers reporting a significant improvement in DNA integrity relative to DGC (p < 0.01-p < 0.001). In practical terms, the Felix™ device featured a standardized 6 min preparation time whereas clinical DGC protocols varied from center to center but generally took around 40 min to complete.

CONCLUSIONS

The Felix™ device is a positive technical development capable of isolating suspensions of highly motile spermatozoa exhibiting low levels of DNA damage in a fraction of the time taken by conventional procedures such as DGC.

A non-randomized clinical trial to determine the safety and efficacy of a novel sperm sex selection technique

The desire to have offspring of a specific sex has a long history but has been particularly present with the appearance of assisted reproduction. However, embryo selection raises ethical concerns. Thus, several techniques to select sex-specific spermatozoa have been proposed but carry limitations. There are many variations of each technique, and some are time consuming and costly. Concerns about effectiveness and safety have also rendered many of them unappealing. Therefore, we propose a novel sperm sex selection technique (SST) that appears to be consistently safe and effective. A single-center, non-randomized clinical trial was designed. We included 1,317 couples, who were assigned to one of two groups: ICSI/PGTA or ICSI/PGTA+GS. Ejaculates from male partners of couples in the ICSI/PGTA+GS group (n = 105) were processed using SST to enrich spermatozoa for their desired sex. Standard sperm processing was carried out for couples undergoing PGT-A solely for aneuploidy (n = 1,212), comprising the ICSI/PGTA control group. To validate the efficacy of our technique, we performed an analysis on spermatozoa pre- and post-selection, followed by an assessment of the proportion of the conceptuses' sex to confirm clinical reliability. We also followed up on ICSI clinical outcomes and child/newborn health to establish the safety of our method. Our main outcome measures included the proportion of spermatozoa and embryos enriched for female and male sex, as well as embryo euploidy rates and ICSI clinical outcomes. These outcomes were compared between the two groups. For the ICSI/PGTA group (n = 1,212) (maternal age, 37.0±4yrs; paternal age, 39.1±6yrs), with ejaculated spermatozoa processed in the standard fashion, 2,303 ICSI cycles (1.2±1) yielded an 81.0% (14,375/17,737) fertilization. PGT-A results indicated a euploidy rate of 73.1% (n = 3,718) for female and 72.4% (n = 3,054) for male embryos. These couples achieved a 76.4% (699/915) implantation and 65.2% (597/915) clinical pregnancy rate, with 551 deliveries (48.5% female, 51.5% male). All 105 men in the ICSI/PGTA+GS group had sperm specimens with an equal sex distribution at baseline. Of them, 59 (paternal age, 40.9±6yrs) who desired female offspring obtained an 81.6% enrichment after SST. They underwent 73 ICSI cycles with their partners (maternal age, 37.9±4yrs), achieving a 77.3% (583/754) fertilization. This resulted in 79.1% (231/292) female embryos that generated a 79.3% (23/29) implantation rate, with 16 singleton deliveries of the desired female sex without major or minor congenital malformations. Forty-six couples (maternal age, 37.3±4yrs; paternal age, 40.7±6yrs) desiring male offspring obtained an 80.8% sperm sex enrichment. They underwent 50 ICSI cycles, achieving a 75.4% (462/613) fertilization and equivalent proportion of male embryos (223/280, 79.6%). Their implantation was 90.5% (19/21), with 13 singleton deliveries of healthy male offspring. Furthermore, 78.8% (182/231) of female and 66.4% (148/223) of male embryos from the ICSI/PGTA+GS cohort were euploid. These euploid rates were comparable to those from the ICSI/PGTA group. In couples undergoing ICSI with PGT-A, SST consistently enriched spermatozoa, resulting in a higher proportion of embryos and thus offspring of the desired sex. Moreover, SST did not impair the fertilization or embryo developmental competence of spermatozoa, nor did it affect offspring health. Trial registration: Clinicaltrials.gov NCT05500573.

O-044 ICSI in the lab: from vintage to AI

With the advent of in vitro fertilization (IVF) by Patrick Steptoe and Bob Edwards in the late 70s, the first conception outside of the human body resulted in the birth of Louise Brown. Although a terrific success, limitations of IVF surfaced, represented by the unexpected complete fertilization failure with suboptimal or dysfunctional spermatozoa.

This prompted curiosity toward individual spermatozoa for a deeper understanding of its role aimed at enhancing the interaction between complementary gametes. Techniques were designed to manipulate the oocytes, such as stripping, partially digesting, or cracking the zona pellucida (ZP). These methods were palliative solutions to overcome fertilization failure and were often plagued by polyspermy. As a result, more direct approaches were implemented to overcome the ZP, such as subzonal injection (SUZI) that although more consistent, was still unable to overcome the shortcomings of dysfunctional spermatozoa. This laid the foundation for the utilization of ICSI that, whilst attempted by some investigators, became popular when Gianpiero Palermo serendipitously inserted one spermatozoon into the ooplasm during SUZI. Consistent fertilization then followed by injecting a cohort of oocytes by ICSI in SUZI cycles, and replacement of these embryos led to 4 pregnancies described in the first clinical ICSI report. To minimize oocyte damage, the procedure was further refined by inducing a deep invagination of the oolemma toward the 9 o’clock position, granting higher chances of post-injection survival.

What set apart ICSI from other forms of ART was that any sperm sample, regardless of quality/quantity, would yield fertilization. Indeed, ICSI is the sole insemination method used with epididymal and testicular spermatozoa and has therefore revolutionized fertility treatment of azoospermic men. Indeed, even immotile testicular spermatozoa can still fertilize and yield successful pregnancies, albeit at a lower rate than their motile counterpart. Also, for these semen sources, aggressive sperm immobilization was introduced to enhance sperm membrane permeabilization and grant optimal fertilization results.

Furthermore, ICSI has transformed the field of reproductive medicine by assisting other reproductive techniques, such as testing embryos for single gene defects to reduce the occurence of sperm DNA contamination, or overcoming the cryostress-induced changes of the ZP during cryopreservation allowing the oocyte to be fertilized at a higher rate. Oocyte cryopreservation now empowers women in their reproductive age to ordain their childbearing future.

ICSI has proven to be the ultimate technique to overcome male infertility and has broadened its indication by yielding consistent fertilization and successful pregnancies in most circumstances, ensuring that men have the chance of fathering their own progeny.

To date, ICSI is applied in several countries, and in some, is performed as the preferred/sole insemination method contributing to the birth of millions of babies worldwide. Thus far, no concerning differences have been seen in the health of ICSI versus standard IVF offspring, or even naturally conceived. In fact, it has been currently established that young adults of both genders born through ICSI retain their reproductive health.

Despite its growing popularity, ICSI does not always succeed but still provides an invaluable platform to deepen our knowledge of gamete biology and helps to investigate/overcome some of the most severe and persistent forms of infertility. For example, combined with assisted gamete treatment, ICSI allows couples plagued by sperm-bound oocyte-activation-deficiency to achieve pregnancy.

The need to increase access and curtail costs of reproductive care has led to the testing of automation in ART. This is also occurring with ICSI and to date, different automated modules have been proposed for oocyte denudation, sperm tracking, and robotic ICSI. Concurrently, there has been an interest in experimenting with artificial intelligence in the IVF laboratory to minimize human shortcomings and ensure that the best spermatozoon is chosen.

Haploidy in somatic cells is induced by mature oocytes in mice

Haploidy is naturally observed in gametes; however, attempts of experimentally inducing haploidy in somatic cells have not been successful. Here, we demonstrate that the replacement of meiotic spindles in mature metaphases II (MII) arrested oocytes with nuclei of somatic cells in the G0/G1 stage of cell cycle results in the formation of de novo spindles consisting of somatic homologous chromosomes comprising of single chromatids. Fertilization of such oocytes with sperm triggers the extrusion of one set of homologous chromosomes into the pseudo-polar body (PPB), resulting in a zygote with haploid somatic and sperm pronuclei (PN). Upon culture, 18% of somatic-sperm zygotes reach the blastocyst stage, and 16% of them possess heterozygous diploid genomes consisting of somatic haploid and sperm homologs across all chromosomes. We also generate embryonic stem cells and live offspring from somatic-sperm embryos. Our finding may offer an alternative strategy for generating oocytes carrying somatic genomes.

P–119 The correlation between sperm chromatin fragmentation and intrauterine insemination outcome

Study question

Does sperm genomic integrity affect the intrauterine insemination (IUI) outcomes in couples with unexplained infertility and young maternal age?

Summary answer

Spermatozoa with higher genomic integrity are correlated with higher clinical pregnancy rates in couples with unexplained infertility undergoing IUI.

What is known already

It is known that elevated sperm chromatin fragmentation (SCF) on the male gamete affects embryo development and implantation. This is particularly relevant in IVF as well as programmed intercourse and IUI. By complementing the standard semen analysis with an SCF assay, we can assess the competence of the male gamete and its ability to generate euploid embryos and healthy offspring. Elevated SCF has been used as a way to identify subtle male factor infertility in couples undergoing IUI with poor pregnancy outcomes in order to plan for further treatments.

Study design, size, duration

This is a retrospective cohort study of IUI outcomes of couples with young maternal age and a negative infertility workup treated at our center from 2016–2020. Terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) assay was used to assess sperm genomic integrity. Couples were grouped based on SCF level: normal (≤15%) or abnormal (&gt;15%). Rates of clinical pregnancy, defined as the presence of a fetal heartbeat, were compared between the groups following IUI.

Participants/materials, setting, methods

A total of 189 consenting couples, in which the female partner had a normal uterine cavity and patent fallopian tubes, underwent 454 IUI attempts. Only women ≤37 years old were included to control for age-related confounding factors. At least 500 spermatozoa were assessed per patient, and a threshold of ≤ 15% was considered normal. Women were either untreated for natural cycle IUI or stimulated with clomiphene citrate, gonadotropins, or Letrozole.

Main results and the role of chance

A total of 454 IUI cycles were reported at our center; 302 of these were carried out in 132 couples in which the male partner had normal SCF averaged at 9.29%. The average maternal age was 34.1±3 years, and the average paternal age was 37.1±5 years. These men had the following semen parameters: a concentration of 46.2±5x106/mL, 43.8±3% motility, and an average SCF of 9.3±3%. There were 45 documented clinical pregnancies (45/302, 14.9%) as confirmed by the presence of at least one fetal heartbeat detected by ultrasound; 26 delivered, 9 are ongoing, 5 were spontaneous abortions, and 5 were lost to follow-up. A total of 57 couples in which the male partner (37.2±5.9 years) had abnormal SCF underwent 152 IUI cycles (maternal age, 34.0±2.7 years). The men had the following semen parameters: an average SCF of 23.8±10 (p &lt; 0.0001), a concentration of 26.0±10 x106/ml, and 40.1±4% motility. These IUI attempts yielded a clinical pregnancy rate of only 4.6% (7/152; P &lt; 0.0001); 4 delivered and 3 were spontaneous abortions.

Limitations, reasons for caution

This study is a retrospective cohort analysis of a relatively small number of patients. Furthermore, most patients were screened for SCF due to at least one prior IUI failure. A prospective, randomized trial, in which men are concurrently screened for SCF levels at the first IUI attempt, would be ideal.

Wider implications of the findings: Assessment of SCF at the initial male infertility screening can be a useful tool to investigate the competence of the male gamete. Screening couples with idiopathic infertility for a subtle male factor would guide those with higher SCF toward alternative reproductive treatments to avoid unnecessary IUI treatments.

Trial registration number

Not applicable

O-119 Evaluating the reproductive potential of azoospermic men by germline mutation profiling

Study question

Can whole exome sequencing (WES) of spermatozoa from azoospermic men identify mutations related to the etiology of their infertility and ability to support a pregnancy?

Summary answer

Key de novo germline mutations that affect sperm production and/or embryo developmental competence may explain reproductive failure in azoospermic men, regardless of the etiology.

What is known already

Azoospermia accounts for approximately 15% of male factor infertility cases. Although it can be caused by pre-testicular factors, the most recognized forms are testicular and post-testicular. While post-testicular azoospermia is mainly due to a mechanical obstruction, testicular azoospermia, the most severe form, is characterized by scattered functional germinal epithelia that strive to support the meiotic process during gamete development. To shed light on the etiology of this condition, genetic studies have been performed, albeit exclusively on peripheral blood. We chose to perform a genomic assessment of spermatozoa to preferentially detect germline mutations that may be passed to the progeny.

Study design, size, duration

In a 2-year period, we recruited infertile men undergoing epididymal aspiration for acquired obstructive azoospermia (OA; n = 19) or testicular retrieval for nonobstructive azoospermia (NOA; n = 10). Four additional men were included as fertile controls. Following WES, copy number variants (CNVs) and gene mutation profiles were compared between the OA and NOA patients, and within those two categories, in relation to whether they generated a clinical pregnancy (fertile) or not (infertile).

Participants/materials, setting, methods

Spermatozoal DNA was extracted and amplified from the surgically retrieved specimens of consenting men (DNA concentration, 762±492 ng/ul; quality, 1.7±0.1 nm). CNVs, gene mutations, duplications, and deletions were detected using the CLC Genomic Server 9.0. Genes were considered duplicated or deleted when the read depth was &gt;1.5 or &lt; 0.5 times the median read depth in the control. Common mutations in the OA and NOA cohorts were assessed according to the couples’ clinical outcome.

Main results and the role of chance

Of 29 couples (maternal age, 41.9±7yrs; paternal age, 42.5±7yrs), 19 OA men underwent epididymal sperm retrieval (1.1±4x106/ml concentration, 9±12% motility) while 10 NOA men underwent testicular biopsy (0.03±0.2x106/ml concentration, 0.5±1% motility). WES did not reveal a significant difference in sperm aneuploidy between the two etiologies (OA, 1.8%; NOA, 1.9%).

In OA patients, only 3 genes were deleted, mainly housekeeping-related, while in the NOA cohort, 5 genes were deleted, involved in RNA transcription (POLR2L) and apoptosis (AP5M1), in addition to spermiogenic functions (AP1S2, AP1G2, APOE).

OA patients and their partners (maternal age, 36.8±4yrs) underwent 19 ICSI cycles that resulted in a pregnancy and delivery rate of 47.4% (9/19). Those able to reproduce (n = 9) shared a mutation in ZNF749, a gene affecting only sperm production. The infertile individuals (n = 10) all had a deletion on PRB1, controlling essential DNA replication.

NOA men and their partners (maternal age, 38.2±2yrs) underwent 10 ICSI cycles, yielding a clinical pregnancy rate of 70% (7/10). The fertile men (n = 7) had a concurrent gene deletion involved in stem cell lineage differentiation (MPIG6B). Their infertile counterparts (n = 3) had deleted genes involved in spermato/spermio-genesis (n = 6) and, most importantly, in early embryonic development (MBD5, CCAR1, PMEPA1, POLK, REC9, REPIN1, MAPRE3, and ARL4C).

Limitations, reasons for caution

This is a novel study with limited observations. The presence of housekeeping-related mutations in fertile OA men as well as the DNA replication mutation in infertile OA patients, considering the acquired condition, remains puzzling. Although maternal age was controlled for, confounding factors related to the female partner cannot be excluded.

Wider implications of the findings

Screening men for germline mutations provides valuable information on their ability to reproduce, regardless of the etiology of azoospermia. Genome profiling was able to identify reasons for failed reproductive performance in azoospermic men, particularly those individuals with secretory azoospermia (NOA). Genomic profiling may identify gametes with retained embryo developmental competence.

Trial registration number

n/a

P–118 A sperm selection technique to mitigate paternal contributions to embryo aneuploidy

Study question

Can microfluidic sperm selection (MFSS) select male gametes without sperm chromatin fragmentation (SCF) and double-stranded DNA breaks (dsDNA) in order to generate euploid conceptuses?

Summary answer

Couples treated by ICSI with MFSS had significantly improved embryo ploidy rates and pregnancy outcomes, demonstrating the efficacy of this novel selection method.

What is known already

SCF has been linked to infertility, specifically to embryo developmental and implantation failure. This damage can be both single-stranded (ssDNA) or double-stranded (dsDNA). Recent studies have shown that dsDNA in particular causes chromosomal aberrations and contributes to embryo aneuploidy, which leads to implantation failure.

Study design, size, duration

Consenting couples treated at our center by intracytoplasmic sperm injection (ICSI) with spermatozoa selected by MFSS were included. The majority of these couples had a medical history significant for elevated SCF, recurrent implantation failure, and embryo aneuploidy. ICSI clinical outcome, as well as preimplantation genetic testing for aneuploidy (PGT-A) and frozen embryo transfer (FET), was recorded and compared to the couples’ historical treatments following sperm selection by density gradient centrifugation (DGC).

Participants/materials, setting, methods

From 2016 to 2020, 51 consenting men had their ejaculates screened for SCF levels by terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) using a commercially available kit. At least 500 spermatozoa were assessed per patient, with a normal threshold of ≤ 15%.

To screen for dsDNA, neutral Comet using a modified in-house protocol was also performed in a pilot study. At least 200 spermatozoa were assessed per patient, with a normal threshold of ≤ 3%.

Main results and the role of chance

A total of 51 men (average age, 41.0±8 years) had mean sperm concentrations of 39.0±33x106/mL, 38.4±12% motility, and 2.1±1% normal morphology. Following DGC and MFSS, the concentrations were 4.7±8 and 4.3±8x106/mL and the motility was 64.0±33 and 98.0±3%, respectively (P &lt; 0.0001). The average SCF decreased from 20.1±18% in the ejaculate to 16±3% following DGC, but was 2.9±4% after MFSS. The dsDNA fell from 3.4±3% in raw specimens to 2.9±1% after DGC, and to only 0.5±0.7% following MFSS (P &lt; 0.0001).

These men underwent ICSI with their female partners (average age, 37.3±4 years), with sperm selected by DGC; they achieved a fertilization rate of 56.4% (337/597) with 26.0% euploid embryos (36/139). FET cycles from these embryos yielded an implantation rate of 8.3% (2/24) and a clinical pregnancy rate (CPR) of 15.4% (2/13), but both miscarried.

These couples then underwent ICSI with MFSS, with a fertilization rate of 78.0% (588/754; P &lt; 0.0001) and 50.0% (172/344; P &lt; 0.0001) euploid embryos after PGT-A. A total of 37 embryos have been replaced, with an implantation rate of 67.6% (25/37; P &lt; 0.0001) and a CPR of 73.5% (25/34; P &lt; 0.001), with an ongoing/delivery rate of 70.6% (24/34; P &lt; 0.0001).

Limitations, reasons for caution

While the oocyte contribution cannot be discounted, MFSS was able to yield spermatozoa that had the highest motility and ability to produce euploid embryos following ICSI.

Wider implications of the findings: The genome and epigenome of the spermatozoon, and their contribution to reproductive outcomes, are being vigorously explored and scrutinized. Alternative approaches to gamete selection, such as MFSS, in couples with elevated SCF and dsDNA provide the best chances for future pregnancies by mitigating embryo aneuploidy.

Trial registration number

Not applicable

O-101 Neospermatogenesis benefits from a three-dimensional culture system

Study question

Does a three-dimensional (3D) culture system increase the efficiency of male germline differentiation of mouse embryonic stem cells (mESC) over a bidimensional method?

Summary answer

Our 3D culture system based on direct spherification proves superior to the standard bidimensional plating in promoting neogametogenesis of mESC into post-meiotic male germ cells.

What is known already

Two-dimensional monolayer cell cultures are common in stem cell research. However, this method does not replicate a physiological 3D spatial relationship and may provide an inaccurate replication of in vivo environments. A 3D spherical structure allows us to mimic the seminiferous tubule, the site of in vivo spermatogenesis. By using spheroids as a scaffold to replicate cell culture systems, we can study spermatogenesis in a controlled setting. Direct spherification, a technique commonly used in molecular gastronomy, provides an opportunity to create spheroids that mimic in vivo events that materialize in the lab

Study design, size, duration

mESCs were initially cultured on a 6-well plate coated with fibroblasts and inserted into sodium alginate spheres. To coax differentiation, spheres (3 to 6 mm in diameter) were plunged directly into differentiation medium (DM) while the control mESC in 6-well dishes were layered with it. Cells obtained from both culture systems were tested by biomarkers for different germ cell stages

Participants/materials, setting, methods

Bidimensional mESC at 80% confluence were differentiated either on a plate or spherified for a 3D culture. Both systems underwent the same timeline of exposure to EpiLC medium with Activin A, bFGF and KSR for 3 days and PGCLC medium with BMP4, LIF, SCF and EGF for 7 days. Differentiated cells were retrieved from each method at day 3 and day 10 to assess for germ line differentiation markers, DAZL, VASA and BOULE

Main results and the role of chance

Under optic visualization through the sphere wall, cellular aggregation was seen on day 2 of culturing in EpiLC medium while this phenomenon was not observed on bidimensional plating. In the conventional method, cells expressed 7% DAZL (spermatogonium cell stage) and 1% VASA (pre-spermatid cell stage) whereas in direct spherification, cells expressed 20% DAZL (P &lt; 0.001) and 15% VASA positivity (P &lt; 0.0001).

To further compare the different methods in later stages of germ-line differentiation, the remaining spheres were cultured in PGCLC medium for 7 days. At day 10, isolated cells were assessed for VASA and DAZL again. In the conventional method, 23% of cells expressed positivity for VASA and 29% DAZL whereas direct spherification achieved a positivity rate of 43% for VASA (P &lt; 0.005) and 45% for DAZL (P &lt; 0.005). This increased expression in both VASA and DAZL signify the increased number of cells undergoing germline differentiation.

Additionally, BOULE was assessed for the presence of meiotic cells such as the spermatocyte. The conventional method yielded &lt; 1% BOULE positivity whereas in direct spherification, there was 10% positivity (P &lt; 0.005).

Direct spherifcation result shows that differentiation almost doubled in comparison to the conventional method, yielding more post-meiotic cells in the same amount of time

Limitations, reasons for caution

Despite a higher differentiation rate in direct spherification, these cells would still need to be tested for their fertilization potential. The ability to achieve fertilization, blastocysts and live pups would provide final proof and reliability of this method of neogametogenesis

Wider implications of the findings

Differentiating ESCs through direct spherification provides an alternative to studying intercellular relationships. This provides an opportunity to study spermatogenesis in more detail by replicating the microenvironment of the seminiferous tubule. Once embryo developmental competence of the de novo gamete is confirmed, this may open a new chapter in human reproduction

Trial registration number

N/A

P–120 Selecting spermatozoa with the highest genomic integrity in order to enhance clinical outcomes in men with high DNA fragmentation levels

Study question

What are the best methods of selecting spermatozoa with the highest genomic integrity in order to improve embryo implantation and term pregnancy rates with ICSI?

Summary answer

Testicular or ejaculate spermatozoa isolated by microfluidic sperm selection (MFSS) were characterized by superior genomic integrity with improved clinical pregnancy and delivery rates.

What is known already

In couples with unexplained infertility, a subtle male factor can often be identified. Both single-strand (ss) and double-strand (ds) DNA nicks and breaks hinder the ability of the male gamete to support embryonic development. Surgical retrieval of spermatozoa from the proximal male genital tract can prevent their exposure to oxidative stress. Moreover, use of membrane-based microfluidics chips has been shown to allow for selection of the most progressively motile spermatozoa with higher genomic integrity.

Study design, size, duration

Over the course of 48 months, 86 consenting men presenting with high sperm chromatin fragmentation (SCF) in their ejaculate with prior ART failure underwent a subsequent cycle with specimens retrieved by testicular biopsy or ejaculate processed by MFSS. A concurrent TUNEL assay was performed on samples collected or selected by each method. Sperm specimens of both origins were utilized for ICSI cycles. Semen parameters, chromatin integrity, and pregnancy outcomes were compared between the two methods.

Participants/materials, setting, methods

Fresh ejaculates from consenting men were collected for standard semen analysis (WHO 2010). Testicular biopsy and MFSS were used to isolate spermatozoa with a higher genomic integrity after previous ART failure. SCF was assessed by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) on at least 500 spermatozoa under a fluorescent microscope with a threshold of ≥ 15%. MFSS was carried out by Zymot® chips. ICSI was performed in the standard fashion.

Main results and the role of chance

A total of 86 men (36.5±5 years) had the following semen parameters: volume of 2.6 ±1mL, concentration of 27.0±33 x 106/mL, 35.6±15% motility, and high SCF (24.1±10%). They underwent 146 ICSI cycles with their partners (maternal age, 33.7±3) resulting in a high incidence of pregnancy loss (100%; 13/13). Of those who failed to conceive, 22 couples used surgically retrieved spermatozoa (SRS) with a concentration of 1.8 ± 4 x 106/mL (P &lt; 0.01), 5.0±11% motility (P &lt; 0.01), and an SCF of 12.6 ± 6% (P &lt; 0.0001). SRS was used in 37 ICSI cycles, yielding a fertilization rate of 61.6% (204/331, P &lt; 0.01), an implantation rate of 10.6% (9/85, P &lt; 0.01), a CPR of 23.5% (8/34, P &lt; 0.01), and a delivery rate of 17.6% (6/34, P &lt; 0.01). Another 24 couples underwent ICSI cycles with ejaculated spermatozoa processed by MFSS with a concentration of 1.8±3 x 106/mL (P &lt; 0.01), but an increased motility of 99±1% (P &lt; 0.01) and an SCF of 1.2 ±1%, lower than both the raw and testicular specimens (P &lt; 0.0001). MFSS-processed specimens resulted in a fertilization rate of 76% (335/441, P &lt; 0.01), an implantation rate of 26.3% (15/57, P &lt; 0.05), and a CPR of 67.9% (19/28, P &lt; 0.01), of which 15 patients delivered and 2 pregnancies are ongoing (89.5%; P &lt; 0.01).

Limitations, reasons for caution

This is a preliminary study on a small number of subjects. A randomized prospective study conducted on a larger cohort would be required to confirm our findings.

Wider implications of the findings: SCF severely affects pregnancy by impairing embryonic development, consequently promoting implantation failure. While retrieving spermatozoa from the germinal epithelium is a viable option, MFSS provides an alternative. Although MFSS requires an adequate number of sperm with good kinetic characteristics, it provides a more palatable option, reducing surgical risk and costs.

Trial registration number

Not applicable

In vitro fertilization and andrology laboratories in 2030

The in vitro fertilization and andrology laboratories are at the center of assisted reproductive technologies and the place where technicians and embryologists manipulate gametes and preimplantation-stage embryos with the goal of achieving the best embryo for transfer. Through the years, these laboratories have seen developments in technique, technology, and testing. The goal of this Views and Interviews series is to bring together the thought leaders in the field and envision what the laboratories will look like in the next 10 years.

Assessing the cognitive and behavioral development of 3-year-old children born from fathers with severe male infertility

BACKGROUND

Despite the large number of babies born worldwide following intracytoplasmic sperm injection, concerns about the procedure's safety still exist owing to the use of suboptimal spermatozoa. Thus, follow-up of children conceived via intracytoplasmic sperm injection is highly recommended. We propose the use of parent-administered questionnaires to monitor the development of offspring conceived via intracytoplasmic sperm injection.

OBJECTIVE

This study aimed to determine whether male infertility treatment affects offspring development.

STUDY DESIGN

We compared obstetrical and neonatal outcomes and physical and psychological development of toddlers conceived via in vitro fertilization and intracytoplasmic sperm injection. Once newborns reached 3 years of age, participating patients were sent a set of parent-administered questionnaires, including the Ages and Stages Questionnaires; Prescreening Developmental Questionnaire 2; Peabody Developmental Motor Scales, Second Edition; Social Skills Rating System; Parenting Stress Index, Third Edition; and Child Behavior Checklist for Ages 2-3. Child development was measured by the Ages and Stages Questionnaires; Prescreening Developmental Questionnaire 2; and Peabody Developmental Motor Scales, Second Edition, questionnaires, whereas Social Skills Rating System; Parenting Stress Index, Third Edition; and Child Behavior Checklist for Ages 2-3 questionnaires were used to measure child behavior. The child's developmental or behavioral outcome was considered "abnormal" when he or she scored below average in ≥2 questionnaires from the respective category. We also conducted subanalyses to assess the effects of male genomic integrity, DNA fragmentation, chemical exposure, utilization of surgically retrieved spermatozoa, and extended embryo culture to determine the development of a child conceived via intracytoplasmic sperm injection.

RESULTS

A total of 12,306 couples met the inclusion criteria for this study; 1914 of 7433 patients (25.8%) who underwent intracytoplasmic sperm injection and 451 of 4873 patients (9.3%) who underwent in vitro fertilization returned the questionnaires. Our comparison of obstetrical outcomes between the 2 groups did not reveal any significant differences in the mode of delivery distribution, with most mothers having uncomplicated vaginal deliveries. Furthermore, gender distribution, gestational ages, and birthweights were also comparable between children conceived via intracytoplasmic sperm injection and in vitro fertilization. However, children conceived via in vitro fertilization displayed impaired developmental characteristics compared with the intracytoplasmic sperm injection-conceived cohort (adjusted odds ratio, 0.72; 95% confidence interval, 0.5-0.9; P=.0004). There was no difference in child behavior. Furthermore, 3 cases of autism were reported, 1 case from the in vitro fertilization group and 2 from the intracytoplasmic sperm injection group, all conceived from couples with an older male partner. Ages and Stages Questionnaires outcomes were also compared for the offspring conceived via in vitro fertilization and intracytoplasmic sperm injection by gender; however, no significant differences were observed. In addition, 5 separate subanalyses were then conducted exclusively for the intracytoplasmic sperm injection-conceived group. Levels of spermatogenic failure, DNA fragmentation, and chemical exposure did not significantly affect offspring development. Interestingly, although the length of embryo culture did not seem to influence child development, the abnormal behavior rate was significantly higher in children from the day 3 embryo transfer cohort (adjusted odds ratio, 0.4; 95% confidence interval, 0.05-0.34; P=.04). Children conceived via intracytoplasmic sperm injection from ejaculated spermatozoa displayed impaired developmental and behavioral characteristics compared with toddlers conceived from surgically retrieved specimens (adjusted odds ratio, 4.9; 95% confidence interval, 1.2-20.7; P=.05).

CONCLUSION

Most children conceived via intracytoplasmic sperm injection and in vitro fertilization are developing well without significant delays. Although the development of a child conceived via intracytoplasmic sperm injection was not affected by most of the variables assessed, those conceived from surgically retrieved spermatozoa were at a considerably lower risk of abnormal developmental and abnormal behavioral characteristics than offspring conceived from ejaculated specimens. However, given the small numbers of respondents available for many subgroups of interest, further studies of outcomes of children born from fathers with severe male factor infertility are warranted.

Thoughts on the popularity of ICSI

Purpose

Intracytoplasmic sperm injection (ICSI) is the most widely utilized assisted reproductive technique (ART) worldwide. In this feature, we review the early assisted fertilization attempts that eventually led to the development of ICSI, and discuss its current utilization in cases of male and non-male factor infertility.

Methods

We researched the literature related to the development, indications, and current use of ICSI, such as sperm structural abnormalities, male genetic indications, surgically retrieved sperm, high sperm chromatin fragmentation, oocyte dysmorphism, and preimplantation genetic testing (PGT). We also describe the potential future applications of ICSI.

Results

This review summarizes the early micromanipulation techniques that led to the inception of ICSI. We also explore its current indications, including non-male factor infertility, where its use is more controversial. Finally, we consider the benefits of future advancements in reproductive biology that may incorporate ICSI, such as in vitro spermatogenesis, neogametogenesis, and heritable genome editing.

Conclusion

The versatility, consistency, and reliability of ICSI have made it the most prevalently utilized ART procedure worldwide.