Use of suboptimal sperm increases the risk of aneuploidy of the sex chromosomes in preimplantation blastocyst embryos

Automatic high-throughput and non-invasive selection of sperm at the biochemical level

BACKGROUND

Sperm selection, a key step in assisted reproductive technology (ART), has long been restrained at the preliminary physical level (morphology or motility); however, subsequent fertilization and embryogenesis are complicated biochemical processes. Such an enormous "gap" poses tough problems for couples dealing with infertility, especially patients with severe/total asthenozoospermia .

METHODS

We developed a biochemical-level, automatic-screening/separation, smart droplet-TO-hydrogel chip (BLASTO-chip) for sperm selection. The droplet can sense the pH change caused by sperm's respiration products and then transforms into a hydrogel to be selected out.

FINDINGS

The BLASTO-chip system can select biochemically active sperm with an accuracy of over 90%, and its selection efficiency can be flexibly tuned by nearly 10-fold. All the substances in the system were proven to be biosafe via evaluating mice fertilization and offspring health. Live sperm down to 1% could be enriched by over 76-fold to 76%. For clinical application to patients with severe/total asthenozoospermia, the BLASTO-chip could select live sperm from human semen samples containing 10% live but 100% immotile sperm. The rates of fertilization, cleavage, early embryos, and blastocysts were drastically elevated from 15% to 70.83%, 10% to 62.5%, 5% to 37.5%, and 0% to 16.67%, respectively.

CONCLUSIONS

The BLASTO-chip represents a real biochemical-level technology for sperm selection that is completely independent of sperm's motility. It can be a powerful tool in ART, especially for patients with severe/total asthenozoospermia.

FUNDING

This work was funded by the Ministry of Science and Technology of China, the Ministry of Education of China, and the Shenzhen-Hong Kong Hetao Cooperation Zone.

The use of preimplantation genetic testing for aneuploidy: a committee opinion

The use of preimplantation genetic testing for aneuploidy (PGT-A) in the United States has been increasing steadily. Moreover, the underlying technology used for 24-chromosome analysis continues to evolve rapidly. The value of PGT-A as a routine screening test for all patients undergoing in vitro fertilization has not been demonstrated. Although some earlier single-center studies reported higher live-birth rates after PGT-A in favorable-prognosis patients, recent multicenter, randomized control trials in women with available blastocysts concluded that the overall pregnancy outcomes via frozen embryo transfer were similar between PGT-A and conventional in vitro fertilization. The value of PGT-A to lower the risk of clinical miscarriage is also unclear, although these studies have important limitations. This document replaces the document of the same name, last published in 2018.

Embryological and clinical outcomes in couples with severe male factor infertility versus normozoospermia

OBJECTIVE

This study evaluated embryological and clinical outcomes in couples with severe male factor infertility versus those with normozoospermia undergoing ICSI and in vitro fertilisation.

METHODS

This multicentre, retrospective cohort study included all couples who had undergone autologous ICSI cycles at My Duc Hospital and My Duc Phu Nhuan Hospital in Vietnam between January 2018 and January 2021 (female age < 35 years and males with severe male factor or normozoospermia based on the World Health Organization 2010 criteria). The primary outcome was the cumulative live birth rate after the first ICSI cycle.

RESULTS

A total of 1296 couples were included, including 648 with severe male factor infertility and 648 with normozoospermia. The number of two pronuclei zygotes, embryos, and frozen embryos was significantly lower in couples with severe male factor infertility compared with normozoospermia (p < 0.05). In contrast, there were no significant differences between the two groups with respect to cumulative pregnancy outcomes, including the live birth rate, and secondary outcomes including clinical pregnancy rate, ongoing pregnancy rate, and miscarriage rate.

CONCLUSION

Severe male factor infertility appeared to have an impact on the fertilisation and early developmental potential of embryos, but sperm quality did not affect cumulative clinical fertility outcomes.

High sperm DNA fragmentation increased embryo aneuploidy rate in patients undergoing preimplantation genetic testing

RESEARCH QUESTION

Is high sperm DNA fragmentation (SDF) associated with a high embryonic aneuploidy rate in patients undergoing intracytoplasmic sperm injection (ICSI)-preimplantation genetic testing (PGT)?

DESIGN

This was a retrospective study of 426 couples with normal karyotypes undergoing ICSI-PGT at the authors' centre from March 2017 to March 2021. SDF was assessed using the sperm chromatin structure assay. The population was divided into low and high SDF groups according to cut-off values found by the receiver operating characteristic (ROC) curve. A 1:1 ratio propensity score matching (PSM) method was used to control for potential confounding factors, and a generalized linear mixed model was established to evaluate the relationship between SDF and the embryonic aneuploidy rate.

RESULTS

The ROC curve indicated a threshold of 30%. In total, 132 couples were included after PSM, and the high SDF group (>30%) had significantly higher SDF (40.74% ± 9.78% versus 15.54% ± 7.86%, P < 0.001) and a higher embryo aneuploidy rate (69.36% versus 53.96%, P < 0.001) compared with the low SDF group (≤30%). The two pronuclear fertilization rate, cleavage rate, rate of high-quality embryos at day 3 rate, blastocyst rate, biochemical pregnancy rate, clinical pregnancy rate, miscarriage rate, live birth rate, caesarean section rate, preterm birth rate, singleton rate and low birthweight rate were similar in both groups (P > 0.05). After PSM, SDF > 30% was significantly correlated with an increased embryo aneuploidy rate after adjusting for all confounding variables (adjusted odds ratio 1.70, 95% CI 1.00-2.88, P = 0.049).

CONCLUSIONS

SDF > 30% was associated with an increased embryo aneuploidy rate in couples with normal karyotypes undergoing PGT, but did not affect embryonic and clinical outcomes after transfer of euploid embryos.

The impact of semen parameters on ICSI and pregnancy outcomes in egg recipient cycles with PGT-A

BACKGROUND

The egg donation model offers an opportunity to isolate the male factor and evaluate its impact on IVF-intracytoplasmic sperm injection and pregnancy outcomes.

OBJECTIVE

To study the effect of non-obstructive azoospermia on intracytoplasmic sperm injection and pregnancy outcomes compared with severe oligozoospermia and mild-to-moderate oligozoospermia in egg recipient cycles.

MATERIALS AND METHODS

This is a retrospective longitudinal cohort study, including 1594 patients who underwent intracytoplasmic sperm injection in egg recipient cycles with preimplantation genetic testing for aneuploidies. The cohort was divided into three groups: couples with non-obstructive azoospermia accounting for 479 patients (30%); couples with severe oligozoospermia (sperm number <5 × 106 /mL), accounting for 442 patients (27.8%); couples with mild-to-moderate oligozoospermia, with sperm number >5 × 106 and <15 × 106 /mL, accounting for 673 patients (42.2%).

RESULTS

The fertilisation rate was significantly reduced in the non-obstructive azoospermia group as compared with the severe oligozoospermia and the mild-to-moderate oligozoospermia group: 30.3% versus 63% and 77.3% (p < 0.05). Logistic regression analysis adjusted for confounders highlighted non-obstructive azoospermia as a negative predictor of obtaining a euploid blastocyst both per injected oocyte and per obtained blastocyst. The miscarriage rate in the non-obstructive azoospermia group was 11.8%; higher than the severe oligozoospermia and mild-to-moderate oligozoospermia groups (7% and 2.7%) (p < 0.05). The live birth rate per embryo transfer (ET) was significantly lower in the non-obstructive azoospermia group compared with the severe oligozoospermia and the mild-to-moderate oligozoospermia group (20.4% vs. 30.3% and 35.4%, p < 0.05). The risk of preterm labour was significantly higher in the non-obstructive azoospermia group, compared with the severe oligozoospermia and mild-to-moderate oligozoospermia group (55.1% vs. 46.8% and 16.1%, p < 0.001), and this difference was observed in both singleton and twin pregnancies.

DISCUSSION AND CONCLUSION

In our retrospective comparative study, non-obstructive azoospermia significantly affects early embryonic potential and live birth rates per cycle and per embryo transfer. It is also associated with higher risk of preterm birth. Future prospective multi-centre studies are needed to highlight the effect of sperm quality on ART and pregnancy outcomes.

Male factor infertility and assisted reproductive technologies: indications, minimum access criteria and outcomes

BACKGROUND

Infertility, which is defined as the inability to conceive after at least 12 months of regular unprotected sexual intercourses, affects about 15-20% of couples worldwide and a male factor is involved in about half of the cases. The development of assisted reproductive technology (ART) made it possible to conceive also to individuals affected from severe oligospermia or azoospermia. However, the impact of the male factor on embryo development, implantation, prevalence of chromosomal abnormalities, genetic and epigenetic alterations, and clinical and obstetric outcomes is still controversial.

PURPOSE

This narrative review examines the indications, minimum access criteria, and outcomes by individual ART technique in relation to the male factor.

Switching to testicular sperm after a previous ICSI failure with ejaculated sperm significantly improves blastocyst quality without increasing aneuploidy risk

PURPOSE

The use of testicular sperm is confined to patients with azoospermia, but there is evidence to support its use in males with poor semen parameters and/or previous intracytoplasmic sperm injection (ICSI) failures with ejaculated spermatozoa. We compared the aneuploidy rate and quality between embryos derived from ICSI cycles with ejaculated sperm (EJ-ICSI) and those from ICSI cycles using testicular spermatozoa (TT-ICSI) within the same couple.

METHODS

Retrospective study of 27 couples who first underwent an EJ-ICSI cycle that did not result in a livebirth and afterwards a TT-ICSI cycle. Only the two closer cycles of each couple were included. Preimplantation genetic test for aneuploidies (PGT-A) was performed in both ICSI cycles and classic parameters of embryo quality were assessed until blastocyst-stage.

RESULTS

A total of 375 embryos from 54 ICSI cycles were evaluated. Aneuploidy rate was measured by two different parameters. Patients undergoing TT-ICSI presented a similar aneuploidy rate as EJ-ICSI group: 30.7% (23.4-38.0) vs 26.8% (18.1-35.5) per inseminated oocytes (P>0.05), and 76.2% (66.2-86.2) vs 72.1% (59.1-85.2) per the total number of biopsied embryos (P>0.05), respectively. Further, the good-quality blastocyst rate per correctly fertilized oocyte was significantly higher in TT-ICSI group (33.6% (30.4-36.9)) than EJ-ICSI group (24.2% (20.3-28.0)) (P<0.001).

CONCLUSIONS

Switching to testicular sperm for ICSI yielded better-quality blastocysts without affecting the chromosomal load of the embryos in non-azoospermic couples with a previous unsuccessful ICSI using ejaculated sperm. This strategy is a good option for couples seeking a livebirth who do not want to use donor sperm.

Preimplantation genetic testing for aneuploidy in severe male factor infertility: protocol for a multicenter randomised controlled trial

INTRODUCTION

Conventional intracytoplasmic sperm injection (ICSI) is a widely used treatment for couples with severe male infertility. However, there are controversies regarding the selection and the damage to gametes during the ICSI procedure. Although preimplantation genetic testing for aneuploidies (PGT-A) can give genetic information about embryos for transfer and improve fertility rate, and it is widely used in women with recurrent spontaneous abortion or advanced age, PGT-A is not only more expensive but also has unclear effectiveness with respect to the improvement of fertility rate among couples with severe male infertility. High-quality, well-powered randomised clinical trials (RCTs) comparing ICSI+PGT-A and ICSI are lacking.

METHODS AND ANALYSIS

This is a protocol for a multicenter, open-label RCT in four reproductive medical centers qualified for PGT technique in China. We will study couples with severe male infertility scheduled for their fertility treatment. After the blastocyst culture, eligible participants are randomised to the ICSI+PGT-A group or the conventional ICSI group in a 1:1 ratio. Other assisted reproductive procedures are similar and parallel between the two groups. The primary outcome will be live birth rate and cumulative live-birth rate . Secondary outcomes will be embryo implantation rate, biochemical pregnancy rate, clinical pregnancy rate, spontaneous abortion rate, ongoing pregnancy rate, preterm birth rate, fetal chromosomal abnormality rate, birth defect rate and treatment complications. To demonstrate or refute a difference between the two groups, we plan to include 188 participants in each group; taking consideration of 20% of dropout, the total target sample size is 450.

ETHICS AND DISSEMINATION

Ethical approval was obtained from International Peace Maternity and Child Health Hospital of Shanghai Jiao Tong University Medical Science Research Ethics Committee (GKLW2016-16). Informed consent will be obtained from each participant. The findings will be disseminated to the public through conference presentations and publication in peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, NCT02941965.

Can sperm quality influence embryo development and its ploidy? Analysis of 811 blastocysts obtained from different sperm sources

The aim of our study was to evaluate the correlation between sperm quality and ploidy status of the derived blastocysts. We performed a retrospective analysis on a restricted pool of patients enrolling only those who had no female factors. Male patients with genetic factors affecting spermatogenesis were also excluded. We chose a maternal age ≤38 years to decrease the female factor, therefore the male factor was the main component of sterility. We divided the patients in four groups based on semen quality and comparing fertilization, pregnancy and euploidy rates above all. In total, 201 intracytoplasmic sperm injection (ICSI) cycles were enrolled in the study. Cycles were divided into four groups, according to semen source: normal semen, oligoasthenoteratozoospermia (OAT), cryptospermia or non-obstructive azoospermia (NOA). An extremely statistically lower fertilization rate was found in NOA patients. Unexpectedly, no differences were detected in blastocyst formation, euploidy, aneuploidy and mosaicism rates among the four groups. Interestingly, we also found a higher abortion rate comparing NOA to normal semen with an odds ratio of 4.67. In our study no statistically significant differences among the analyzed groups were found, showing little or no effect at all using spermatozoa from different semen sources or quality. This may be linked to the oocyte competence of fixing sperm DNA damage and it could be hypothesized that only sperm with a good rate of DNA integrity are able to fertilize the oocyte, explaining why poor quality semen is reflected in a low fertilization rate without effect on ploidy.

Society for Maternal-Fetal Medicine Consult Series #60: Management of pregnancies resulting from in vitro fertilization

The use of assisted reproductive technology has increased in the United States in the past several decades. Although most of these pregnancies are uncomplicated, in vitro fertilization is associated with an increased risk for adverse perinatal outcomes primarily caused by the increased risks of prematurity and low birthweight associated with in vitro fertilization pregnancies. This Consult discusses the management of pregnancies achieved with in vitro fertilization and provides recommendations based on the available evidence. The recommendations by the Society for Maternal-Fetal Medicine are as follows: (1) we suggest that genetic counseling be offered to all patients undergoing or who have undergone in vitro fertilization with or without intracytoplasmic sperm injection (GRADE 2C); (2) regardless of whether preimplantation genetic testing has been performed, we recommend that all patients who have achieved pregnancy with in vitro fertilization be offered the options of prenatal genetic screening and diagnostic testing via chorionic villus sampling or amniocentesis (GRADE 1C); (3) we recommend that the accuracy of first-trimester screening tests, including cell-free DNA for aneuploidy, be discussed with patients undergoing or who have undergone in vitro fertilization (GRADE 1A); (4) when multifetal pregnancies do occur, we recommend that counseling be offered regarding the option of multifetal pregnancy reduction (GRADE 1C); (5) we recommend that a detailed obstetrical ultrasound examination (CPT 76811) be performed for pregnancies achieved with in vitro fertilization and intracytoplasmic sperm injection (GRADE 1B); (6) we suggest that fetal echocardiography be offered to patients with pregnancies achieved with in vitro fertilization and intracytoplasmic sperm injection (GRADE 2C); (7) we recommend that a careful examination of the placental location, placental shape, and cord insertion site be performed at the time of the detailed fetal anatomy ultrasound, including evaluation for vasa previa (GRADE 1B); (8) although visualization of the cervix at the 18 0/7 to 22 6/7 weeks of gestation anatomy assessment with either a transabdominal or endovaginal approach is recommended, we do not recommend serial cervical length assessment as a routine practice for pregnancies achieved with in vitro fertilization (GRADE 1C); (9) we suggest that an assessment of fetal growth be performed in the third trimester for pregnancies achieved with in vitro fertilization; however, serial growth ultrasounds are not recommended for the sole indication of in vitro fertilization (GRADE 2B); (10) we do not recommend low-dose aspirin for patients with pregnancies achieved with IVF as the sole indication for preeclampsia prophylaxis; however, if 1 or more additional risk factors are present, low-dose aspirin is recommended (GRADE 1B); (11) given the increased risk for stillbirth, we suggest weekly antenatal fetal surveillance beginning by 36 0/7 weeks of gestation for pregnancies achieved with in vitro fertilization (GRADE 2C); (12) in the absence of studies focused specifically on timing of delivery for pregnancies achieved with IVF, we recommend shared decision-making between patients and healthcare providers when considering induction of labor at 39 weeks of gestation (GRADE 1C).

The paternal toolbox for embryo development and health

The sperm is essential for reconstitution of embryonic diploidy and highly specialized developmental functions. Immediately after gamete fusion, the sperm-borne PLC-zeta triggers activation, generating intracellular free Ca2+ oscillations. Mutations in the PLC-zeta encoding gene are associated with the absence of this factor in mature sperm and inability to achieve fertilization. Sperm play also a role in the greater game of the choreography of fertilization. In the human, the sperm centrioles are introduced into the oocyte environment with gamete fusion. They interact with the oocyte cytoskeletal apparatus to form a functional pair of centrosomes and ultimately regulate pronuclear juxtaposition in preparation for the first cleavage. As a consequence, the fidelity of chromosome segregation during the first cell divisions depends on the function of sperm centrioles. Sperm DNA integrity is essential for embryo development and health. Damaged DNA does not impact on the sperm fertilization ability following ICSI. However, detrimental effects emerge at pre- and post-implantation stages. Sperm-specific epigenetic factors also play an active role in the regulation of embryonic development, as shown by correlations between reduced embryo morphological quality and incorrect chromatin packaging during spermiogenesis or abnormal methylation of sperm CpG islands. This functional landscape demonstrates that the contribution of the sperm to development goes far beyond its well-established role in fertilization. Clinical studies confirm this view and indicate sperm function as a crucial aspect of research to increase the efficacy of assisted reproduction treatments.

A systematic review and meta-analysis on the association between ICSI and chromosome abnormalities

BACKGROUND

In the decade following the introduction of ICSI, a higher prevalence of de novo chromosome abnormalities, in particular sex chromosome and autosomal structural abnormalities, as well as inherited abnormalities was described in children conceived by ICSI compared to both naturally conceived (NC) children and children conceived by standard IVF. The explanation for the observed increase in prevalence is not clear and has been suggested to reflect parental factors (e.g. age or sperm quality) or to be a result of the ICSI procedure itself. Over the years, the procedure, as well as the patient group, and indications for ICSI treatment have changed.

OBJECTIVE AND RATIONALE

The objective of this systematic review and meta-analysis was to assess the prevalence of chromosome abnormalities in ICSI pregnancies and children and to examine any potentially increased risk compared to standard IVF and NC.

SEARCH METHODS

Pubmed, Embase, Cochrane Libraries and Web of Science up to October 2020 were searched. Primary outcome measures were overall chromosome abnormalities and de novo abnormalities (including sex chromosome abnormalities and autosomal abnormalities). The secondary outcome was inherited abnormalities. We followed the PRISMA guidelines and relevant meta-analyses were performed.

OUTCOMES

The search included 4648 articles, out of which 27 met the inclusion criteria, and 19 were included in quantitative synthesis (meta-analyses). The prevalence of chromosome abnormalities varied considerably between studies, possibly explained by large differences in sample size and patient demographics. Only five studies were eligible for pooled analyses on adjusted data. All studies had a critical risk of bias. Results from pooled adjusted data showed no evidence of an increased risk of overall chromosome abnormalities when comparing ICSI to either standard IVF (aOR 0.75 (95% CI 0.41-1.38)) or NC (aOR 1.29 (95% CI 0.69-2.43)). In contrast, meta-analyses on unadjusted data showed an increased risk of overall chromosome abnormalities in ICSI compared to both standard IVF (OR 1.42 (95% CI 1.09-1.85)) and NC (OR 2.46 (95% CI 1.52-3.99)) and an increased risk of de novo abnormalities in ICSI compared to NC (OR 2.62 (95% CI 2.07-3.31)). Yet, based on a very low certainty of evidence, the conclusion remains, that no indication of an increased risk of chromosome abnormalities in ICSI offspring could be found. If an increased risk of chromosome abnormalities in selected ICSI offspring should exist, the absolute risk continues to be small.

WIDER IMPLICATIONS

This review provides an extensive overview of the existing evidence on the relationship between ICSI and chromosome abnormalities in the offspring. We highlight the need for well-designed large, prospective, controlled studies with systematic cytogenetic testing. Existing data are limited and, in many cases, marred by critical levels of bias.

Comparison of preimplantation genetic testing for aneuploidy versus intracytoplasmic sperm injection in severe male infertility

The retrospective cohort study was conducted to evaluate the effectiveness of preimplantation genetic testing for aneuploidy (PGT-A) for severe male factor (SMF) infertility on pregnancy outcomes in comparison with intracytoplasmic sperm injection (ICSI). A total of 206 couples with SMF were included in the study, among which, 102 couples underwent ICSI with next-generation sequencing (NGS)-based PGT-A (the PGT-A group), while 104 underwent ICSI only (the control group). Results showed while no differences were noted in clinical pregnancy rate (CPR) (66.7% versus. 69.9%, p = .64) and ongoing pregnancy rate (OPR) (62.2% versus. 54.7%, p = .29) per transfer between groups, early miscarriage rate (EMR) per transfer was significantly lower (6.7% versus. 21.6%, p = .02) in the PGT-A group. Cumulative OPR per patient remained similar between groups (54.9% versus. 55.8%, p = .90). Results of multivariable logistic regression also demonstrated the use of PGT-A was significantly associated with lower EMR (adjusted OR 0.17, 95%CI 0.05-0.55) in SMF, while it was not related to cumulative OPR. In conclusion, our results showed that NGS-based PGT-A can improve pregnancy outcomes for couples with SMF by significantly decreasing EMR without compromising cumulative OPR, indicating that NGS-based PGT-A could be offered as an appropriate approach for couples with SMF.

Do donor spermatozoa improve reproductive outcomes after oocyte donation failure? A retrospective analysis of cumulative live birth rates per donor oocyte consumed

RESEARCH QUESTION

Do donor spermatozoa improve IVF outcomes after first oocyte donation failure?

DESIGN

Retrospective, multicentre study including couples undergoing oocyte donation cycles using autologous or donor spermatozoa after a failed first attempt. Male partners were further characterized as normozoospermic or oligoasthenoteratospermic, i.e. fewer than 5 million motile progressive spermatozoa in the ejaculate. The main outcomes measured were live birth rate (LBR) per embryo transfer, LBR per number of embryos transferred, and cumulative LBR (CLBR) considering oocytes consumed in the previous donation cycles.

RESULTS

Analysis comprised 6065 cycles of oocyte donation failure; among these, subgroup analyses by sperm quality comprised 4113 cycles with severe male factor and 1150 cycles with suboptimal/normal spermatozoa. Sperm replacement in the first cycle after failure increased LBR per embryo transfer (OR 2.21, 95% CI 1.7-2.8, P < 0.001) and per number of embryos transferred (OR 2.46, 95% CI 1.9-3.1, P < 0.001) for normospermic and oligoasthenoteratospermic men. Replacement by the third cycle after failure was less beneficial (LBR per embryo transfer: OR 1.35, 95% CI 0.9-2.1, P = 0.16; LBR per embryos transferred: OR 1.33, 95% CI 0.9-2.0, P = 0.186). Kaplan-Meier curves of CLBR per oocyte fertilized with autologous or donor spermatozoa were statistically different (P < 0.001) and demonstrate how each additional oocyte may affect success based on sperm source (donor/autologous).

CONCLUSIONS

Donor spermatozoa improved outcomes when used after an initial failed oocyte donation cycle. The CLBR curves can be used to determine the cumulative chances of live birth using either autologous or donor spermatozoa, providing guidance on when to replace spermatozoa.

Frequency of Sperm Aneuploidy in Oligoasthenoteratozoospermic (OAT) Patients by Comprehensive Chromosome Screening: A Proof of Concept

Background:

Embryonic aneuploidy usually results in implantation failure and miscarriage. Considering significantly high frequency of sperm aneuploidy reported in oligoasthenoteratozoospermia (OAT) using fluorescence in situ hybridization (FISH) in limited number of chromosomes and lack of comprehensive chromosome screening (CCS) in OAT, the aim of this study was applying CCS in OAT sperm and comparison of the results with FISH findings.

Methods:

Five OAT patients with normal blood karyotypes and history of implantation failure were included. The successfully amplified samples, each containing two sperm, were analyzed by array comparative genomic hybridization (aCGH). FISH was utilized mainly depending on the aneuploidies found by aCGH to assess their frequencies in total sperm population.

Results:

In aCGH for 30 sperm, aneuploidy was found in 66% of samples. Following the study of 4300 sperm by FISH, an average of 55.46% aneuploidy was observed. No pregnancy was resulted with normal partners.

Conclusion:

Using aCGH, some abnormalities were observed that are not typically considered in sperm FISH studies. Despite small sample size of the comprehensive study, like other similar studies, the frequency of aneuploidies was considerable and similar to FISH. Aneuploidies revealed by aCGH at single sperm resolution were different from sperm population detected by FISH. Considering high frequency of aneuploidy in OATs sperm, preimplantation genetic testing for aneuploidy (PGT-A) can be used for in transfer of chromosomally normal embryos.

Is there an association between paternal age and aneuploidy? Evidence from young donor oocyte-derived embryos: a systematic review and individual patient data meta-analysis

BACKGROUND

Delayed parenthood, by both women and men, has become more common in developed countries. The adverse effect of advanced maternal age on embryo aneuploidy and reproductive outcomes is well known. However, whether there is an association between paternal age (PA) and embryonic chromosomal aberrations remains controversial. Oocyte donation (OD) is often utilized to minimize maternal age effects on oocyte and embryo aneuploidy, thus providing an optimal model to assess the effect of PA. Several studies have revealed a higher than expected rate of aneuploidy in embryos derived from young oocyte donors, which warrants examination as to whether this may be attributed to advanced PA (APA).

OBJECTIVE AND RATIONALE

The objective of this systematic review and individual patient data (IPD) meta-analysis is to evaluate existing evidence regarding an association between PA and chromosomal aberrations in an OD model.

SEARCH METHODS

This review was conducted according to PRISMA guidelines for systematic reviews and meta-analyses. Medline, Embase and Cochrane databases were searched from inception through March 2020 using the (MeSH) terms: chromosome aberrations, preimplantation genetic screening and IVF. Original research articles, reporting on the types and/or frequency of chromosomal aberrations in embryos derived from donor oocytes, including data regarding PA, were included. Studies reporting results of IVF cycles using only autologous oocytes were excluded. Quality appraisal of included studies was conducted independently by two reviewers using a modified Newcastle-Ottawa Assessment Scale. A one-stage IPD meta-analysis was performed to evaluate whether an association exists between PA and aneuploidy. Meta-analysis was performed using a generalized linear mixed model to account for clustering of embryos within patients and clustering of patients within studies.

OUTCOMES

The search identified 13 032 references, independently screened by 2 reviewers, yielding 6 studies encompassing a total of 2637 IVF-OD cycles (n = 20 024 embryos). Two 'low' quality studies using FISH to screen 12 chromosomes on Day 3 embryos (n = 649) reported higher total aneuploidy rates and specifically higher rates of trisomy 21, 18 and 13 in men ≥50 years. One 'moderate' and three 'high' quality studies, which used 24-chromosome screening, found no association between PA and aneuploidy in Day 5/6 embryos (n = 12 559). The IPD meta-analysis, which included three 'high' quality studies (n = 10 830 Day 5/6 embryos), found no significant effect of PA on the rate of aneuploidy (odds ratio (OR) 0.97 per decade of age, 95% CI 0.91-1.03), which was robust to sensitivity analyses. There was no association between PA and individual chromosome aneuploidy or segmental aberrations, including for chromosomes X and Y (OR 1.06 per decade of age, 95% CI 0.92-1.21). Monosomy was most frequent for chromosome 16 (217/10802, 2.01%, 95% CI 1.76-2.29%) and trisomy was also most frequent for chromosome 16 (194/10802, 1.80%, 95% CI 1.56-2.06%).

WIDER IMPLICATIONS

We conclude, based on the available evidence, that APA is not associated with higher rates of aneuploidy in embryos derived from OD. These results will help fertility practitioners when providing preconception counselling, particularly to older men who desire to have a child.

Sperm chromosome abnormalities in patients with normal karyotype and in translocation carriers: clinical relevance for assisted reproductive technology

RESEARCH QUESTION

What is the proportion of chromosomally abnormal spermatozoa in men with a history of reproductive failure, including patients with normal karyotype and carriers of translocations? Should this analysis be included in a clinical setting to define the best treatment options for infertile couples?

DESIGN

Aneuploidy for chromosomes XY, 13, 15, 16, 17, 18, 21, 22 was tested by fluorescent in-situ hybridization (FISH) in 1665 samples from couples with normal karyotype having had at least three previous IVF failures, miscarriages, or both (group-A). A FISH test was also carried out in 76 samples from carriers of translocations (group B) to detect the proportion of spermatozoa with unbalanced rearrangement.

RESULTS

In group A, the lowest incidence of aneuploid sperm cells was found in men with normozoospermia (1.3%, range 0.09-6.31%) compared with men with moderate oligoasthenoteratozoospermia (2.1%, range 0.41-16.6%, P < 0.001), severe oligoasthenoteratozoospermia (4.7%, range 0.53-30.77, P < 0.001), microepididymal sperm aspiration (3.1%, range 1.19-24.24, P < 0.001) and testicular sperm extraction samples (5.8%, range 1.54-33.3, P < 0.001). In group B, the proportion of spermatozoa with unbalanced rearrangement was significantly higher in reciprocal (63%, range 10.0-87.6%) than in Robertsonian translocations (16%, range 4.3-51.0%, P < 0.001).

CONCLUSIONS

Patients with poor prognosis of term pregnancy tend to generate high proportions of chromosomally abnormal spermatozoa, especially in severe male factor cases. Corresponding frequencies occur at wide ranges; therefore, the FISH test is needed to assess the proportion of spermatozoa with altered chromosome condition. A flowchart, which included the FISH test, was designed to assist clinicians guide couples with poor prognosis of pregnancy, on the most indicated treatment options.

Clinical application of embryo aneuploidy testing by next-generation sequencing

We review here the evolution in the field of embryo aneuploidy testing over the last 20 years, from the analysis of a subset of chromosomes by fluorescence in situ hybridisation to the transition toward a more comprehensive analysis of all 24 chromosomes. This current comprehensive aneuploidy testing most commonly employs next-generation sequencing (NGS). We present our experience in over 130 000 embryo biopsies using this technology. The incidence of aneuploidy was lower in trophectoderm biopsies compared to cleavage-stage biopsies. We also confirmed by NGS that embryo aneuploidy rates increased with increasing maternal age, mostly attributable to an increase in complex aneuploid embryos. In contrast, the number of MII oocytes retrieved or the use of oocyte vitrification did not affect aneuploidy rates. Similarly, neither maternal age, oocyte number, nor oocyte vitrification affected the incidence of mosaicism. Analysis of clinical outcomes, indications, and potential benefits of embryo aneuploidy testing revealed advanced maternal age as the most favored group, with some evidence of improved delivery rate per transfer as well as decreased miscarriage rates and time to pregnancy. Other indications are: recurrent miscarriage, repetitive implantation failure, severe male factor, previous trisomic pregnancy, and good prognosis patients mainly undergoing single embryo transfer, with the latter indication used to reduce the occurrence of multiple pregnancies without compromising cycle outcome. In conclusion, NGS has become the most appropriate technology for aneuploidy testing in trophectoderm biopsies, with accurate results, high throughput, and cost efficiency. This technology can be also applied to the analysis of the embryonic cell free DNA released to the culture media at blastocyst stage. This is a promising approach towards a non-invasive preimplantation genetic testing of aneuploidy.

Advanced paternal age is associated with an increased risk of spontaneous miscarriage: a systematic review and meta-analysis

BACKGROUND

Although spontaneous miscarriage is the most common complication of human pregnancy, potential contributing factors are not fully understood. Advanced maternal age has long been recognised as a major risk factor for miscarriage, being strongly related with fetal chromosomal abnormalities. The relation between paternal age and the risk of miscarriage is less evident, yet it is biologically plausible that an increasing number of genetic and epigenetic sperm abnormalities in older males may contribute to miscarriage. Previous meta-analyses showed associations between advanced paternal age and a broad spectrum of perinatal and paediatric outcomes. This is the first systematic review and meta-analysis on paternal age and spontaneous miscarriage.

OBJECTIVE AND RATIONALE

The aim of this systematic review and meta-analysis is to evaluate the effect of paternal age on the risk of spontaneous miscarriage.

SEARCH METHODS

PubMed, Embase and Cochrane databases were searched to identify relevant studies up to August 2019. The following free text and MeSH terms were used: paternal age, father's age, male age, husband's age, spontaneous abortion, spontaneous miscarriage, abortion, miscarriage, pregnancy loss, fetal loss and fetal death. PRISMA guidelines for systematic reviews and meta-analysis were followed. Original research articles in English language addressing the relation between paternal age and spontaneous miscarriage were included. Exclusion criteria were studies that solely focused on pregnancy outcomes following artificial reproductive technology (ART) and studies that did not adjust their effect estimates for at least maternal age. Risk of bias was qualitatively described for three domains: bias due to confounding, information bias and selection bias.

OUTCOMES

The search resulted in 975 original articles. Ten studies met the inclusion criteria and were included in the qualitative synthesis. Nine of these studies were included in the quantitative synthesis (meta-analysis). Advanced paternal age was found to be associated with an increased risk of miscarriage. Pooled risk estimates for miscarriage for age categories 30-34, 35-39, 40-44 and ≥45 years of age were 1.04 (95% CI 0.90, 1.21), 1.15 (0.92, 1.43), 1.23 (1.06, 1.43) and 1.43 (1.13, 1.81) respectively (reference category 25-29 years). A second meta-analysis was performed for the subgroup of studies investigating first trimester miscarriage. This showed similar pooled risk estimates for the first three age categories and a slightly higher pooled risk estimate for age category ≥45 years (1.74; 95% CI 1.26, 2.41).

WIDER IMPLICATIONS

Over the last decades, childbearing at later ages has become more common. It is known that frequencies of adverse reproductive outcomes, including spontaneous miscarriage, are higher in women with advanced age. We show that advanced paternal age is also associated with an increased risk of spontaneous miscarriage. Although the paternal age effect is less pronounced than that observed with advanced maternal age and residual confounding by maternal age cannot be excluded, it may have implications for preconception counselling of couples comprising an older aged male.

Is there a role for phosphodiesterase inhibitors in the treatment of male subfertility?

Intracytoplasmic sperm injection (ICSI) is frequently used to overcome severe deficits in semen quality. Concerns, however, are arising over its increasing use for non-male factor infertility. Moreover, increased risk of cardiovascular disease, congenital abnormalities, aneuploidies and childhood cancers have all been reported in the literature in relation to ICSI and it is possible that the quality of sperm chosen for injection may be an important factor in these unwanted outcomes. Given the wider adoption of ICSI to treat beyond the requirements of male infertility alone, research focussed on alternative methods to diagnose and treat the infertile couple is gaining increasing attention. This review focuses on the information available to date on the use of non-selective phosphodiesterase inhibitors (PDEI), specifically pentoxifylline (PF), caffeine (CF) and theophylline (TP) to stimulate sperm motility, thereby potentially reducing the need for ICSI in certain patient groups who may benefit from either expectant management or from a less stressful, minimally invasive and inexpensive treatment such as intrauterine insemination (IUI). The review focuses firstly on the mechanism of action of PDEI followed by treatment effects on sperm parameters such as motility and hyperactivated motility and sperm DNA integrity. Specific clinical implications are discussed that outline the potential role of PDEI in clinical practice and highlights areas in need of further research.

Preimplantation genetic testing for aneuploidy in severe male factor infertility

RESEARCH QUESTION

Does the use of preimplantation genetic testing for aneuploidies (PGT-A) improve outcomes in couples with severe male factor infertility (SMFI)?

DESIGN

This retrospective cohort study included SMFI cases that underwent blastocyst transfer with/without PGT-A. Inclusion criteria were SMFI (azoospermia and sperm count <1 million/ml), women aged 25-39 years, single vitrified-warmed blastocyst transfer, and no intracavitary pathologies. Patients were divided into PGT-A and non-PGT-A groups. The primary outcome was live birth rate (live birth of an infant after 24 weeks of gestation); secondary outcomes were implantation and clinical pregnancy rates.

RESULTS

The study included 266 SMFI cases (90 and 176 in the PGT-A and non-PGT-A groups, respectively). Men and women in the PGT-A group were significantly older than those in the non-PGT-A group. The groups did not differ in terms of male factor categories, sperm collection methods or additional female factors. Live birth rates in the PGT-A and non-PGT-A groups were 55.6% and 51.1%, respectively (odds ratio [OR] 1.19, 95% confidence interval [CI] 0.71-1.98, P = 0.495). The implantation rates were 65.6% and 64.2%, respectively (OR 1.06, 95% CI 0.62-1.80, P = 0.827). The clinical pregnancy rates were 62.2% and 58.0%, respectively (OR 1.19, 95% CI 0.71-2.01, P = 0.502). The use of PGT-A was not an independent factor for live birth (aOR 1.33, 95% CI 0.66-2.70, P = 0.421). Advanced age in women was the only independent factor associated with live birth (aOR 0.46, 95% CI 0.22-0.96, P = 0.041).

CONCLUSIONS

The use of PGT-A does not seem to be an independent factor associated with live birth per transfer in couples with SMFI.

Preimplantation Genetic Testing: Where We Are Today

BACKGROUND

Preimplantation genetic testing (PGT) is widely used today in in-vitro fertilization (IVF) centers over the world for selecting euploid embryos for transfer and to improve clinical outcomes in terms of embryo implantation, clinical pregnancy, and live birth rates.

METHODS

We report the current knowledge concerning these procedures and the results from different clinical indications in which PGT is commonly applied.

RESULTS

This paper illustrates different molecular techniques used for this purpose and the clinical significance of the different oocyte and embryo stage (polar bodies, cleavage embryo, and blastocyst) at which it is possible to perform sampling biopsies for PGT. Finally, genetic origin and clinical significance of embryo mosaicism are illustrated.

CONCLUSIONS

The preimplantation genetic testing is a valid technique to evaluated embryo euploidy and mosaicism before transfer.

The role of total chromosomal disomy in human spermatozoa as a predictor of the outcome of pre-implantation genetic screening

OBJECTIVE

To assess the efficacy of sperm disomy rate as a predictor of preimplantation genetic screening (PGT-A) outcomes.

DESIGN

Retrospective cohort study.

SETTING

Andrology laboratory and in vitro fertilization center.

PATIENT(S)

All patients (n = 123) who underwent sperm fluorescence in situ hybridization and PGT-A at the China International Trust and Investment Corporation Xiangya Reproductive and Genetic Hospital between January 2015 and November 2018 were included.

INTERVENTION(S)

Sperm samples of all patients evaluated for elevated disomy levels of 24 chromosomes using multicolor sperm fluorescence in situ hybridization and all embryos were cultured and biopsied at the blastocyst stage for PGT-A.

MAIN OUTCOME MEASURE(S)

The relationship between the whole genome of sperm disomy rate and PGT-A outcome and the predictive effect of the whole genome of sperm disomy rate on PGT-A outcome.

RESULT(S)

A statistically significant correlation was observed between the sperm disomy rate and PGT-A outcome. Many confounders were considered, such as patients' factors, semen or laboratory characteristics, which may affect PGT-A outcome. Regression analysis excluding these confounding factors indicated a 2.071-fold decrease in odds of probability of not obtaining any euploid embryo to transfer for every 1% decrease in total disomy rate. Based on a total disomy rate threshold of 4.84%, the prediction ability of total disomy rate on PGT-A outcome reached 75.6%.

CONCLUSION(S)

There is a negative correlation between the whole genome of sperm disomy rate and PGT-A outcome. It is a potential role for whole genome of sperm disomy rate in the PGT-A patients as a predictor, as well as in future genetic counselling. Based on these results, genetic counselors can advise couples on the risk of not obtaining any euploid embryo and help them choose the best reproductive and diagnostic method.

Paternal age, body mass index, and semen volume are associated with chromosomal aberrations-related miscarriages in couples that underwent treatment by assisted reproductive technology

We investigated the effects of paternal characteristics, including age, body mass index (BMI), and semen parameters on chromosomal aberration-related miscarriages in couples that underwent treatment with assisted reproductive technology (ART). Single nucleotide polymorphism (SNP) array analysis showed chromosomal aberrations in 60.2% (557/925) of miscarried fetuses, including trisomy in 73.1% (407/557) of cases. There were higher chromosomal aberration rates in fetuses for men aged 20-24 years and ≥30 years compared with controls. After adjusting for age and BMI of the female partners, and the BMI and semen parameters of the males, there was no statistically significant effect of paternal age ≥30 years on the risk of chromosomal aberrations-related miscarriages. However, the odds of chromosomal abnormality-related miscarriage were 148% higher for the youngest fathers (age: 20-24 years) than fathers aged 25-29 years [adjusted odds ratio (OR): 2.48, 95% confidence interval (CI): 1.03-5.96; P=0.042]. Furthermore, high male BMI (adjusted OR: 1.56, 95% CI: 1.14-2.14; P=0.005) and low semen volume (adjusted OR: 2.09, 95% CI: 1.06-4.11; P=0.034) were associated with increased risk of chromosomal aberration-related miscarriages. These findings demonstrate that very young paternal age, high BMI, and low semen volume are associated with increased risk of chromosomal aberration-related miscarriages in couples undergoing ART treatment.

The impact of male infertility or intracytoplasmic sperm injection technique on perinatal outcomes

Objective: The aim of this study was to evaluate the impact of male infertility or intracytoplasmic sperm injection (ICSI) technique on perinatal outcomes.Materials and methods: A retrospective cohort study included patients with singleton live births after fresh-cycle embryo transfer that occurred between 1^st January 2016 and 31^st May 2018. The patients were divided into four groups: (1) IVF treatment without male infertility; (2) ICSI treatment without male infertility; (3) ICSI treatment with male infertility; and (4) IVF treatment with male infertility.Result: In total, 2118 patients were analyzed. When comparing perinatal outcomes between the four groups, there were significant differences with regard to gender proportions of offspring and GDM. No statistically significant differences were reported in the incidence of preterm birth, gestational hypertension, placenta previa, fetal malformation, macrosomia, or low birthweight. A separate multiple logistic regression model was performed for each abnormal perinatal outcome to eliminate confounding factors, with the exception of GDM, the above abnormal perinatal outcomes still did not differ significantly when comparing the four groups. However, the incidence of GDM was higher in the third group than it was in the first group. The proportion of male births was significantly decreased in the third and fourth groups.Conclusion: The results showed that ICSI may be associated with the risk of GDM in abnormal perinatal outcomes, but the risk is not due to male infertility. However, male infertility may reduce the proportion of male births.

High rates of aneuploidy, mosaicism and abnormal morphokinetic development in cases with low sperm concentration

Purpose

The aim of our study was to evaluate the impact of severe male infertility (SMF) on the chromosomal status of embryos and any possible correlation between chromosomal status and embryo morphokinetics in younger women using data obtained from comprehensive preimplantation genetic tests.

Methods

The trial was conducted in an ART and Reproductive Genetics Centre between 2011 and 2018. A total of 326 cycles in cases with SMF where the female partner’s age was ≤ 35 years were evaluated. SMF is defined as sperm concentration below 5 mil/ml (million per milliliter) and divided into three subgroups according to sperm concentrations: 1–5 mil/ml, < 1mil/ml and testicular sperm. The control group of 190 cycles had normal sperm parameters.

Results

Significantly lower chromosomal euploidy rates were found in the testicular sperm group compared with the normal sperm controls when the female age was ≤ 35 years. In SMF, statistically significantly affected chromosomes were 2, 10, 11, 17, 21 and sex chromosomes. The mosaicism and abnormal morphokinetic development rates were higher in the SMF group than in control group, and this difference was significant when testicular sperm was used.

Conclusion

Lower euploidy rates, higher mosaicism rates and a higher incidence of abnormal morphokinetic development were observed in cases with testicular sperm with female partners ≤ 35 years compared with normal sperm controls. These findings suggest that PGT-A may be advisable in severe male infertility cases. Furthermore, the correlation between morphokinetics and chromosomal status was greatly reduced or absent in these most severe forms of male infertility, thus the need for new morphokinetic models.

Electronic supplementary material

The online version of this article (10.1007/s10815-019-01673-w) contains supplementary material, which is available to authorized users.

Intracytoplasmic sperm injection for male infertility and consequences for offspring

Intracytoplasmic sperm injection (ICSI) has become the most commonly used method of fertilization in assisted reproductive technology. The primary reasons for its popularity stem from its effectiveness, the standardization of the procedure, which means that it can easily be incorporated into the routine practice of fertility centres worldwide, and the fact that it can be used to treat virtually all forms of infertility. ICSI is the clear method of choice for overcoming untreatable severe male factor infertility, but its (over)use in other male and non-male factor infertility scenarios is not evidence-based. Despite all efforts to increase ICSI efficacy and safety through the application of advanced sperm retrieval and cryopreservation techniques, as well as methods for selecting sperm with better chromatin integrity, the overall pregnancy rates from infertile men remain suboptimal. Treating the underlying male infertility factor before ICSI seems to be a promising way to improve ICSI outcomes, but data remain limited. Information regarding the health of ICSI offspring has accumulated over the past 25 years, and there are reasons for concern as risks of congenital malformations, epigenetic disorders, chromosomal abnormalities, subfertility, cancer, delayed psychological and neurological development, and impaired cardiometabolic profile have been observed to be greater in infants born as a result of ICSI than in naturally conceived children. However, as subfertility probably influences the risk estimates, it remains to be determined to what extent the observed adverse outcomes are related to parental factors or associated with ICSI.

Prevalence of XXY karyotypes in human blastocysts: multicentre data from 7549 trophectoderm biopsies obtained during preimplantation genetic testing cycles in IVF

STUDY QUESTION

Which is the prevalence of a 47,XXY karyotype in human blastocysts biopsied during preimplantation genetic testing for aneuploidies (PGT-A) cycles?

SUMMARY ANSWER

The prevalence of a 47,XXY karyotype amongst male blastocysts without autosomal aneuploides is ~1%.

WHAT IS KNOWN ALREADY

The prevalence of Klinefelter syndrome is estimated as 0.1-0.2% in male newborns. However, the KS phenotype is extremely variable and there are men with a 47,XXY karyotype and less evident signs, who may go undetected. No risk factor for the 47,XXY karyotype in products of conception has been yet clearly defined, and no data are available regarding the prevalence of this karyotype among human preimplantation embryos.

STUDY DESIGN, SIZE, DURATION

This multicentre cohort study involved 7549 blastocysts obtained during 2826 PGT-A cycles performed between April 2013 and September 2017 at six IVF clinics in Italy.

PARTICIPANTS/MATERIALS, SETTING, METHODS

During 2826 PGT-A cycles, 7549 blastocysts underwent trophectoderm biopsy and quantitative-PCR-based comprehensive chromosomal testing to predict the karyotype of the corresponding embryos. The results were also presented according to ranges of maternal and paternal age at oocyte retrieval as well as sperm factor and blastocyst quality. Univariate and multivariate logistic regression analyses were conducted to investigate the correlation of possible confounding factors with the prevalence of 47,XXY karyotype.

MAIN RESULTS, THE ROLE OF CHANCE

Overall, 62 blastocysts were 47,XXY or had an XXY karyotype associated with autosomal aneuploidies. After exclusion of the latter, the prevalence of a 47,XXY karyotype among male blastocysts without autosomal aneuploidies was 0.9% (n = 17/1794). A significant correlation was only found for maternal age and blastocyst quality (OR: 1.20, 95% CI: 1.01-1.42; P = 0.04 and OR: 1.6, 95% CI: 1.13-2.45; P = 0.01).

LIMITATIONS, REASONS FOR CAUTION

These retrospective data have been produced based on a population of infertile couples undergoing IVF and PGT-A, and the women were mainly of advanced maternal age. Moreover, the qPCR technique is validated only to detect full-chromosome uniform aneuploidies in trophectoderm biopsies.

WIDER IMPLICATIONS OF THE FINDINGS

The 0.9% prevalence of the 47,XXY karyotype among male blastocysts, when compared with the 0.1-0.2% prevalence reported in the prenatal and postnatal periods, suggests four possible scenarios that require further investigations: (i) the latter prevalence is underestimated; (ii) 47,XXY blastocysts result in a lower implantation rate than euploid embryos (estimated to be ≈50%); (iii) 47,XXY blastocysts result in a higher early miscarriage rate than euploid embryos (estimated to be ≈10%); or (iv) infertile patients of advanced maternal age and referred to IVF/PGT-A produce a higher rate of 47,XXY blastocysts.

STUDY FUNDING/COMPETING INTEREST(S)

None.

TRIAL REGISTRATION NUMBER

N/A.

The role of chromosome segregation and nuclear organisation in human subfertility

Spermatogenesis is central to successful sexual reproduction, producing large numbers of haploid motile male gametes. Throughout this process, a series of equational and reductional chromosome segregation precedes radical repackaging of the haploid genome. Faithful chromosome segregation is thus crucial, as is an ordered spatio-temporal ‘dance’ of packing a large amount of chromatin into a very small space. Ergo, when the process goes wrong, this is associated with an improper chromosome number, nuclear position and/or chromatin damage in the sperm head. Generally, screening for overall DNA damage is relatively commonplace in clinics, but aneuploidy assessment is less so and nuclear organisation studies form the basis of academic research. Several studies have focussed on the role of chromosome segregation, nuclear organisation and analysis of sperm morphometry in human subfertility observing significant alterations in some cases, especially of the sex chromosomes. Importantly, sperm DNA damage has been associated with infertility and both extrinsic (e.g. lifestyle) and intrinsic (e.g. reactive oxygen species levels) factors, and while some DNA-strand breaks are repaired, unexpected breaks can cause differential chromatin packaging and further breakage. A ‘healthy’ sperm nucleus (with the right number of chromosomes, nuclear organisation and minimal DNA damage) is thus an essential part of reproduction. The purpose of this review is to summarise state of the art in the fields of sperm aneuploidy assessment, nuclear organisation and DNA damage studies.

Chromosomal analysis in IVF: just how useful is it?

Designed to minimize chances of genetically abnormal embryos, preimplantation genetic diagnosis (PGD) involves in vitro fertilization (IVF), embryo biopsy, diagnosis and selective embryo transfer. Preimplantation genetic testing for aneuploidy (PGT-A) aims to avoid miscarriage and live born trisomic offspring and to improve IVF success. Diagnostic approaches include fluorescence in situ hybridization (FISH) and more contemporary comprehensive chromosome screening (CCS) including array comparative genomic hybridization (aCGH), quantitative polymerase chain reaction (PCR), next-generation sequencing (NGS) and karyomapping. NGS has an improved dynamic range, and karyomapping can detect chromosomal and monogenic disorders simultaneously. Mosaicism (commonplace in human embryos) can arise by several mechanisms; those arising initially meiotically (but with a subsequent post-zygotic 'trisomy rescue' event) usually lead to adverse outcomes, whereas the extent to which mosaics that are initially chromosomally normal (but then arise purely post-zygotically) can lead to unaffected live births is uncertain. Polar body (PB) biopsy is the least common sampling method, having drawbacks including cost and inability to detect any paternal contribution. Historically, cleavage-stage (blastomere) biopsy has been the most popular; however, higher abnormality levels, mosaicism and potential for embryo damage have led to it being superseded by blastocyst (trophectoderm - TE) biopsy, which provides more cells for analysis. Improved biopsy, diagnosis and freeze-all strategies collectively have the potential to revolutionize PGT-A, and there is increasing evidence of their combined efficacy. Nonetheless, PGT-A continues to attract criticism, prompting questions of when we consider the evidence base sufficient to justify routine PGT-A? Basic biological research is essential to address unanswered questions concerning the chromosome complement of human embryos, and we thus entreat companies, governments and charities to fund more. This will benefit both IVF patients and prospective parents at risk of aneuploid offspring following natural conception. The aim of this review is to appraise the 'state of the art' in terms of PGT-A, including the controversial areas, and to suggest a practical 'way forward' in terms of future diagnosis and applied research.

Long-term clinical outcomes of testicular sperm extraction and intracytoplasmic sperm injection for infertile men

Purpose

To find the best methods to achieve the highest pregnancy and birth rates for couples needing testicular sperm extraction (TESE)‐intracytoplasmic sperm injection (ICSI).

Methods

Retrospectively studied were 801 patients with male factor infertility who had undergone TESE‐ICSI between April, 1996 and July, 2016 and who had been categorized into four groups: obstructive azoospermia (OA); non‐obstructive azoospermia (NOA); Klinefelter syndrome (KS); and cryptozoospermia (Crypt). The sperm retrieval rate, hormone levels, fertilization rate (FR), pregnancy rate (PR), and birth rate (BR) after ICSI among three groups were compared: fresh testicular sperm (FS)‐fresh oocytes (FO) (Group I); frozen‐thawed testicular sperm‐FO (Group II); and FS‐vitrified‐warmed oocytes (Group III).

Results

The testicular sperm recovery rate was 57.8% (463/801): 89.6% in the Crypt, 97.1% in the OA, 28.9% in the NOA, and 42.2% in the KS groups. The follicle‐stimulating hormone levels were significantly higher in the NOA and KS groups and the testosterone levels were significantly lower in the KS group. The FR, PR, and BR were: 65.2%, 43.2%, and 28.5% in group I; 59.2%, 33.4%, and 18.7% in group II; and 56.4%, 33.8%, and 22.1% in group III.

Conclusion

Intracytoplasmic sperm injection with FS‐FO achieved the best PR and BR. It should be considered what to do in cases with no testicular sperm by TESE. The authors hope that ICSI with donor sperm will be allowed in Japan in the near future.

Are blastocyst aneuploidy rates different between fertile and infertile populations?

PURPOSE

This study aimed to determine if patients with infertility or recurrent pregnancy loss have higher rates of embryo aneuploidy than fertile controls.

METHODS

This was a retrospective review of all pre-implantation genetic screening (PGS) cases processed by a single reference lab prior to March 2014 after a blastocyst biopsy. Cases were excluded if no indication for PGS was designated or patients were translocation carriers. The fertile control group consisted of patients undergoing IVF with PGS for sex selection only. The comparison cohorts included those with recurrent pregnancy loss, male factor infertility, unexplained infertility, prior failed IVF, or previous aneuploid conceptions. A quasi-binomial regression model was used to assess the relationship between the dependent variable, aneuploidy rate and the independent variables, maternal age and reason for PGS. A quasi-Poisson regression model was used to evaluate the relationship between similar independent variables and the number of blastocyst biopsies per case.

RESULTS

The initial study population consisted of 3378 IVF-PGS cycles and 18,387 analyzed trophectoderm samples. Controlling for maternal age, we observed an increased rate of aneuploidy among patients with recurrent pregnancy loss (OR 1.330, p < 0.001), prior aneuploid pregnancy (OR 1.439, p < 0.001), or previous failed IVF cycles (OR 1.356, p = 0.0012) compared to fertile controls. Patients with unexplained and male factor infertility did not have a significantly different aneuploidy rate than controls (p > 0.05). The increase in aneuploidy in patients with RPL and prior IVF failure was driven by both an increase in meiotic (OR 1.488 and 1.508, p < 0.05) and mitotic errors (1.269 and 1.393, p < 0.05) relative to fertile controls, while patients with prior aneuploid pregnancies had only an increased risk of meiotic error aneuploidies (OR 1.650, p < 0.05).

CONCLUSIONS

Patients with recurrent pregnancy loss, previous IVF failures, and prior aneuploid pregnancies have a significantly higher, age-independent, aneuploidy rate compared to patients without infertility.

Process and Pitfalls of Sperm Cryopreservation

Sperm cryopreservation has been utilized routinely for over 40 years to preserve fertility in men undergoing cancer therapy and allow conception for infertile couples. This article provides a concise and up-to-date review of the literature and covers the latest advances in sperm cryopreservation and its array of clinical indications. Over recent years, the scope of clinical indications used for sperm cryopreservation has expanded widely. Consequently, more patient groups are eligible for sperm freezing, requiring specialist resources and higher running costs. Although sperm cryopreservation prior to cancer therapy is readily available in many countries, referral rates by oncology specialists and levels of patient engagement with cryopreservation services are both reported as low. Furthermore, sperm banking continues to raise ethical issues such whether sperm donation should be anonymous and whether sperm can be utilized posthumously by the surviving partner without consent from the patient. This review focuses on the technological advances and ethical controversies in sperm cryopreservation, and how better understanding of these issues could lead to improved access to fertility preserving treatment for patients.

Genetic risk of Klinefelter's syndrome in assisted reproductive technology

Aim

The main cause of Klinefelter's syndrome (KS) has been believed to be XY sperm. Accordingly, in the intracytoplasmic sperm injection treatment of patients with KS, hereditary KS has been a concern. Therefore, this study attempted to estimate the risk before and after the assisted reproductive technology.

Methods

First, in order to validate the safety of the gametes of the patients with KS, a fluorescent in situ hybridization (FISH) analysis, following an original cell identification method using 1052 testicular gametes of 30 patients, was conducted. Second, in the resultant 45 babies, cytogenetic and physical-cognitive screening data were analyzed. In addition, a first attempt was conducted to investigate the origin of the extra X chromosome in 11 patients with KS by using 12 X-chromosome short tandem repeat (STR) analysis in order to estimate the paternal contribution to KS.

Results

No sex chromosomally abnormal gamete was found in the FISH analysis and the babies were normal genetically, physically, and cognitively. In the STR, it was confirmed that most (7/11) of the patients with KS resulted from the fertilization of the XX oocytes, suggesting that a baby with KS that had been reported previously might not have resulted from XY sperm.

Conclusion

These results indicate that the risk of assisted reproductive technology for patients with KS is not as high as previously expected.