Paternal contribution to aneuploidy in preimplantation embryos

Epigallocatechin-3-gallate improves the quality of maternally aged oocytes

The decline in female fertility as age advances is intricately linked to the diminished developmental potential of oocytes. Despite this challenge, the strategies available to enhance the quality of aged oocytes remain limited. Epigallocatechin-3-gallate (EGCG), characterised by its anti-inflammatory, antioxidant and tissue protective properties, holds promise as a candidate for improving the quality of maternally aged oocytes. In this study, we explored the precise impact and underlying mechanisms of EGCG on aged oocytes. EGCG exhibited the capacity to enhance the quality of aged oocytes both in vitro and in vivo. Specifically, the application of EGCG in vitro resulted in noteworthy improvements, including an increased rate of first polar body extrusion, enhanced mitochondrial function, refined spindle morphology and a reduction in oxidative stress. These beneficial effects were further validated by the improved fertility observed among aged mice. In addition, our findings propose that EGCG might augment the expression of Arf6. This augmentation, in turn, contributes to the assembly of spindle-associated F-actin, which can contribute to mitigate the aneuploidy induced by the disruption of spindle F-actin within aged oocytes. This work thus contributes not only to understanding the role of EGCG in bolstering oocyte health, but also underscores its potential as a therapeutic intervention to address fertility challenges associated with advanced age.

Reproductive and obstetric outcomes in TESE-ICSI cycles: A comparison between obstructive and non-obstructive azoospermia

PURPOSE

Comparison of intracytoplasmic sperm injection cycles with testicular sperm extraction in obstructive azoospermia and non-obstructive azoospermia are limited, and few studies have addressed obstetric and neonatal outcomes.

DESIGN

This study analyzed couples who underwent testicular sperm extraction-intracytoplasmic sperm injection cycles for obstructive azoospermia and non-obstructive azoospermia to determine whether impaired spermatogenesis in non-obstructive azoospermia patients would lead to worse reproductive outcomes and higher rates of pregnancy complications and fetal anomalies. This study is a retrospective, single-center analysis of all testicular sperm cycles performed between January 1, 2001 and December 31, 2020.

RESULTS

A total of 392 couples were considered in the study, leading to 1066 induction cycles, 620 (58.2%) from patients with obstructive azoospermia and 446 (41.8%) from non-obstructive azoospermia. The cumulative delivery rate did not significantly differ between the two groups (34% vs. 31%; p = 0.326). The miscarriage rate was similar between obstructive azoospermia and non-obstructive azoospermia patients. Fertilization rate instead showed a statistically significant difference (obstructive azoospermia: 66.1 ± 25.7 vs. non-obstructive azoospermia: 56.1 ± 27.0; p < 0.001). The overall maternal complication rate in the non-obstructive azoospermia group was higher (10.7% vs. 18.4%; p = 0.035), but there was no statistical significance for each pathology. There was no statistical difference in gestational age between the two groups for both single and twin pregnancies. Seven cases of congenital defects occurred in the obstructive azoospermia group, while two cases occurred in the non-obstructive azoospermia group.

CONCLUSIONS

Despite impaired spermatogenesis in non-obstructive azoospermia patients, there were no substantial differences in reproductive outcomes compared to patients with obstructive azoospermia, even in terms of obstetric safety and neonatal well-being.

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.

Aneuploidy in mammalian oocytes and the impact of maternal ageing

During fertilization, the egg and the sperm are supposed to contribute precisely one copy of each chromosome to the embryo. However, human eggs frequently contain an incorrect number of chromosomes - a condition termed aneuploidy, which is much more prevalent in eggs than in either sperm or in most somatic cells. In turn, aneuploidy in eggs is a leading cause of infertility, miscarriage and congenital syndromes. Aneuploidy arises as a consequence of aberrant meiosis during egg development from its progenitor cell, the oocyte. In human oocytes, chromosomes often segregate incorrectly. Chromosome segregation errors increase in women from their mid-thirties, leading to even higher levels of aneuploidy in eggs from women of advanced maternal age, ultimately causing age-related infertility. Here, we cover the two main areas that contribute to aneuploidy: (1) factors that influence the fidelity of chromosome segregation in eggs of women from all ages and (2) factors that change in response to reproductive ageing. Recent discoveries reveal new error-causing pathways and present a framework for therapeutic strategies to extend the span of female fertility.

Protamines and DNA integrity as a biomarkers of sperm quality and assisted conception outcome

Present research aim was to identify functional tests in semen associated with DNA damage and chromatin maturity (protamination) which predict the outcome in assisted reproduction. Couples were grouped according to male partner semen parameters, into normozoospermia (NZs), severe male factor (SMF) and mild male factor (MMF). DNA fragmentation index (DFI) in spermatozoa was analysed by sperms chromatin dispersion (SCD), sperm chromatin structure assay (SCSA) and acridine orange testing (AOT). Chromomycin A3 (CMA3) and toluidine blue (TB) staining to measure sperm chromatin maturity (CM). DFI and chromatin decondensation were significantly lower in N compared to male factor categories (MMF and SMF). Aneuploidy embryos were significantly higher in couples with male factor infertility (MMF and SMF). A positive correlation was observed between fertilization rate (FR) and live birth rate (LBR) with sperm concentration, motility, vitality, normal sperm morphology and negative correlation between sperm DFI and sperm CM. No correlation was observed between embryo aneuploidy and sperm DFI or CM. Lower percentage of spermatozoa chromatin integrity are associated with low fertilization and live birth rate. Male factor infertility, due to impaired semen parameters and chromatin defects could be regarded in future as an indication of IVF/ICSI, and predictor of assisted reproductive techniques outcome.

Diagnostics and Management of Male Infertility in Primary Ciliary Dyskinesia

Primary ciliary dyskinesia (PCD), a disease caused by the malfunction of motile cilia, manifests mainly with chronic recurrent respiratory infections. In men, PCD is also often associated with infertility due to immotile sperm. Since causative mutations for PCD were identified in over 50 genes, the role of these genes in sperm development should be investigated in order to understand the effect of PCD mutations on male fertility. Previous studies showed that different dynein arm heavy chains are present in respiratory cilia and sperm flagellum, which may partially explain the variable effects of mutations on airways and fertility. Furthermore, recent studies showed that male reproductive tract motile cilia may play an important part in sperm maturation and transport. In some PCD patients, extremely low sperm counts were reported, which may be due to motile cilia dysfunction in the reproductive tract rather than problems with sperm development. However, the exact roles of PCD genes in male fertility require additional studies, as do the treatment options. In this review, we discuss the diagnostic and treatment options for men with PCD based on the current knowledge.

Assisted reproductive technologies and the risk of stillbirth in singleton pregnancies: a systematic review and meta-analysis

OBJECTIVE

To identify the risk of stillbirth from in vitro types of assisted reproductive technologies compared with spontaneous conception (SC), limited to singleton births.

DESIGN

Systematic literature search and search chaining on online databases: PubMed, Embase, and Scopus.

SETTING

Not applicable.

PATIENT(S)

Singleton pregnancies from in vitro fertilization (IVF) or fertilization by IVF and intracytoplasmic sperm injection (IVF-ICSI).

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Adjusted odds ratio for stillbirth or prevalence of stillbirth in case-control groups of IVF/IVF-ICSI singletons and SCs, respectively, in matched studies.

RESULT(S)

A total of 19 studies were included, and study quality was mixed. Ten studies qualified for inclusion to the meta-analysis, which revealed a significantly increased risk of stillbirth in IVF/IVF-ICSI compared with that in SC (odds ratio [95% confidence interval]: 1.82 [1.37-2.42]), and there was no evidence of publication bias.

CONCLUSION(S)

In vitro fertilization and IVF-ICSI treatment increases the risk of stillbirth compared with natural conception.

CLINICAL TRIAL REGISTRATION NUMBER

PROSPERO 216768.

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.

The Effect of Teratozoospermia on Sex Chromosomes in Human Embryos

Purpose

The aim of this study is to evaluate the effect of abnormal semen morphology on the frequency of sex chromosomal abnormalities in embryos obtained by ICSI, which represents the first to be studied in Egyptian population.

Methods

Forty-two couples suffering from male infertility due to teratozoospermia were divided into two groups: patients with severe and moderate teratozoospermia (group A and B, respectively). All involved couples were subjected to careful history taking and had a normal clinical examination and karyotype. Females were subjected to hormonal assays, pelvic ultrasound, hysterosalpingography and yielded normal results, while male partners were subjected to computerized semen analysis. Preimplantation genetic diagnosis was performed for all suitably developed embryos including embryo biopsy, fixation of biopsied cells and fluorescent in situ hybridization (FISH) analysis.

Results

Couples included in the two groups were found to be homogenous in terms of age of both partners and duration of infertility. Interpretation of FISH results was performed by evaluation of embryos’ chromosomal constitution as regards abnormalities in chromosomes X, Y and 18. Twenty-seven embryos (48.2%) were found chromosomally abnormal in group A, while only 14 embryos (25.0%) were found chromosomally abnormal in group B. Aneuploidies involved only sex chromosomes were tripled in group A embryos when compared to their frequency in group B embryos (26.8% and 8.3%, respectively) with statistically significant difference between the two groups (p=0.002). Monosomies were the most common type of aneuploidy and were significantly higher in group A (14.3%) when compared to group B (3.6%) (p=0.047). Embryos with mosaic abnormalities were more common in group A (12.5%) when compared to group B (3.6%), however not statistically significantly different (p= 0.162). A significant difference between the two studied groups as regards the total number of potentially viable chromosomal abnormalities detected and the potentially viable sex chromosomal aneuploidies detected (p<0.001 and p=0.002), respectively.

Conclusion

The cases with severe teratozoospermia undergoing ICSI treatment can display a higher rate of sex chromosome aneuploidies in their embryos (threefold) than cases with moderate teratozoospermia.

The complex relationship between female age and embryo euploidy

BACKGROUND

Female age is the strongest predictor of embryo chromosomal abnormalities and has a nonlinear relationship with the blastocyst euploidy rate: with advancing age there is an acceleration in the reduction of blastocyst euploidy. Aneuploidy was found to significantly increase with maternal age from 30% in embryos from young women to 70% in women older than 40 years old. The association seems mainly due to chromosomal abnormalities occurring in the oocyte. We aimed to elaborate a model for the blastocyst euploid rate for patients undergoing in-vitro fertilization/intra cytoplasmic sperm injection (IVF/ICSI) cycles using advanced machine learning techniques.

METHODS

This was a retrospective analysis of IVF/ICSI cycles performed from 2014 to 2016. In total, data of 3879 blastocysts were collected for the analysis. Patients underwent PGT-Aneuploidy analysis (PGT-A) at the Center for Reproductive Medicine of European Hospital (Rome, Italy) have been included in the analysis. The method involved whole-genome amplification followed by array comparative genome hybridization. To model the rate of euploid blastocysts, the data were split into a train set (used to fit and calibrate the models) and a test set (used to assess models' predictive performance). Three different models were calibrated: a classical linear regression; a gradient boosted tree (GBT) machine learning model; a model belonging to the generalized additive models (GAM).

RESULTS

The present study confirms that female age, which is the strongest predictor of embryo chromosomal abnormalities, and blastocyst euploidy rate have a nonlinear relationship, well depicted by the GBT and the GAM models. According to this model, the rate of reduction in the percentage of euploid blastocysts increases with age: the yearly relative variation is -10% at the age of 37 and -30% at the age of 45. Other factors including male age, female and male Body Mass Index, fertilization rate and ovarian reserve may only marginally impact on embryo euploidy rate.

CONCLUSIONS

Female age is the strongest predictor of embryo chromosomal abnormalities and has a non-linear relationship with the blastocyst euploidy rate. Other factors related to both the male and female subjects may only minimally affect this outcome.

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.

Characteristics of the IVF Cycle that Contribute to the Incidence of Mosaicism

Highly sensitive next-generation sequencing (NGS) platforms applied to preimplantation genetic testing for aneuploidy (PGT-A) allow the classification of mosaicism in trophectoderm biopsies. However, the incidence of mosaicism reported by these tests can be affected by a wide number of analytical, biological, and clinical factors. With the use of a proprietary algorithm for automated diagnosis of aneuploidy and mosaicism, we retrospectively analyzed a large series of 115,368 trophectoderm biopsies from 27,436 PGT-A cycles to determine whether certain biological factors and in vitro fertilization (IVF) practices influence the incidence of overall aneuploidy, whole uniform aneuploidy, mosaicism, and TE biopsies with only segmental aneuploidy. Older female and male patients showed higher rates of high-mosaic degree and whole uniform aneuploidies and severe oligozoospermic patients had higher rates of mosaicism and only segmental aneuploidies. Logistic regression analysis identified a positive effect of female age but a negative effect of embryo vitrification on the incidence of overall aneuploid embryos. Female age increased whole uniform aneuploidy rates but decreased only segmental aneuploidy and mosaicism, mainly low-mosaics. Conversely, higher ovarian response decreased whole uniform aneuploidy rates but increased only segmental aneuploidies. Finally, embryo vitrification decreased whole uniform aneuploidy rates but increased mosaicism, mainly low-mosaics, compared to PGT-A cycles with fresh oocytes. These results could be useful for clinician’s management of the IVF cycles.

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

Background

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

Methods

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

Results

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

Conclusions

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

Is there a correlation between paternal age and aneuploidy rate? An analysis of 3,118 embryos derived from young egg donors

OBJECTIVE

To investigate a possible correlation between chromosomal aberrations and paternal age, analyzing embryos derived from young oocyte donors, with available preimplantation genetic testing for aneuploidy results from day 5/6 trophectoderm biopsy obtained by next-generation sequencing for all 24 chromosomes.

DESIGN

Retrospective cohort study.

SETTING

Canadian fertility centre.

PATIENT(S)

A total of 3,118 embryos from 407 male patients, allocated into three paternal age groups: group A, ≤39 years (n = 203); group B, 40-49 years (n = 161); group C, ≥50 years (n = 43).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The primary outcomes were aneuploidy, euploidy, mosaicism, and blastocyst formation rates. Secondary endpoints were comparison of specific chromosome aneuploidy, segmental and complex (involving two chromosomes + mosaicism >50%) aneuploidy, and analysis of overall percentage of chromosomal gains and losses within each group.

RESULT(S)

The study included 437 in vitro fertilization (IVF) antagonist cycles using 302 oocyte donors in which preimplantation genetic testing for aneuploidy was performed. Overall, 70.04% of embryos were euploid, 13.9% were aneuploid, and 16.06% were mosaic. No significant differences among paternal age groups A, B, and C were found in euploidy rates (69.2%, 70.6%, 71.4%, respectively), aneuploidy rates (14.7%, 12.8%, 13.9%, respectively) or mosaicism rates (16.1%, 16.6%, 13.6%; respectively). The fertilization rate was lower in group C compared with group B (76.35% vs. 80.09%). No difference was found in blastocyst formation rate between the study groups (median 52% [interquartile range, 41%, 67%] vs. 53% [42%, 65%] vs. 52% [42%, 64%], respectively). A generalized linear mixed model regression analysis for embryo ploidy rates found older oocyte donor age to be independently associated with embryo aneuploidy (odds ratio = 1.041; 95% CI, 1.009-1.074). The rate of segmental aneuploidies was significantly higher in the older versus younger paternal age group (36.6% vs. 19.4%).

CONCLUSION(S)

No association was found between paternal age and aneuploidy rates in embryos derived from IVF cycles using young oocyte donors, after adjusting for donor, sperm, and IVF cycle characteristics. Advanced paternal age ≥ 50, compared with younger paternal ages, was associated with a lower fertilization rate and increased rate of segmental aberrations.

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.

Effect of Interval between Human Chorionic Gonadotropin Priming and Ovum Pick-up on the Euploid Probabilities of Blastocyst

This retrospective study attempts to elucidate the relevance of the interval between human chorionic gonadotropin priming and oocyte pick-up (hCG-OPU) to the euploidy probability of biopsied blastocysts in preimplantation genetic tests for aneuploidy (PGT-A) cycles. A total of 1889 blastocysts from 511 patients undergoing PGT- A cycles were used. An analysis of generalized estimating equations (GEE) was used to identify whether the hCG–OPU interval is associated with euploidy probabilities of blastocysts. Accordingly, maternal age (OR: 0.925, 95% CI: 0.903–0.948, p < 0.001) and the hCG–OPU interval (OR: 1.138, 95% CI: 1.028–1.260, p = 0.013) were the two significant factors associated with the euploidy probabilities. The Cochran-Armitage trend test demonstrated that the blastocyst euploidy percentage increased progressively with the increasing hCG-OPU interval in normal responders (p = 0.006) and advanced maternal age (age ≥38 years; p = 0.020) groups. In normal responders, the euploidy rate was highest in the 38–39 h interval (43.1%, 47/109). In contrast, the euploidy rate was lowest in the 34–35 h interval (28.7%, 29/105). In conclusion, the present study demonstrated that at an hCG-OPU interval between 34–39 h, the longer the hCG-OPU interval, the higher the probability of euploidy for blastocysts.

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.

Sperm DNA damage causes genomic instability in early embryonic development

Genomic instability is common in human embryos, but the underlying causes are largely unknown. Here, we examined the consequences of sperm DNA damage on the embryonic genome by single-cell whole-genome sequencing of individual blastomeres from bovine embryos produced with sperm damaged by γ-radiation. Sperm DNA damage primarily leads to fragmentation of the paternal chromosomes followed by random distribution of the chromosomal fragments over the two sister cells in the first cell division. An unexpected secondary effect of sperm DNA damage is the induction of direct unequal cleavages, which include the poorly understood heterogoneic cell divisions. As a result, chaotic mosaicism is common in embryos derived from fertilizations with damaged sperm. The mosaic aneuploidies, uniparental disomies, and de novo structural variation induced by sperm DNA damage may compromise fertility and lead to rare congenital disorders when embryos escape developmental arrest.

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.

Male factor infertility impacts the rate of mosaic blastocysts in cycles of preimplantation genetic testing for aneuploidy

PURPOSE

In this study, we tested the hypothesis that, in PGT-A cycles, decreased semen quality is associated with increased rates of mosaic blastocysts.

METHODS

In a retrospective analysis, three hundred and forty PGT-A cycles are divided into study groups according to semen quality. Cycles were initially divided into two groups, discerning couples with absence of male factor of infertility (non-male factor: NMF; N = 146 cycles) from couples with a male factor of infertility (MF; N = 173 cycles). Couples with severe male factor (SMF) infertility (n = 22) were assessed separately. Embryos were cultured to the blastocyst stage and chromosomally assessed by array comparative genomic hybridization (aCGH). The study did not involve specific interventions.

RESULTS

The reproductive outcome of MF and NMF groups did not indicate statistically significant differences. However, while no differences were found between MF and NMF groups in terms of euploid or aneuploid blastocysts rates, a significantly higher rate of mosaic blastocysts was observed in the MF group (3.6% vs. 0.5%, respectively; P = 0.03). A similar pattern of results was observed in the SMF group when compared with those of the other PGT-A cycles taken together (no SMF). In particular, a significantly higher rate of mosaic blastocysts was observed in the SMF group (7.7% and 1.8%, respectively; P = 0.008).

CONCLUSIONS

The study outcome strongly suggests that compromised semen quality is associated with increased rates of mosaic blastocysts analysed in PGT-A cycles. Sperm assessment appears therefore as an important factor in the determination of embryo development and for a more precise prognostic assessment of PGT-A cases.

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.

Endocrine and reproductive profile of boys and young adults conceived after ICSI

PURPOSE OF REVIEW

The impact of intracytoplasmic sperm injection (ICSI), on the reproductive health of the offspring is largely unknown. Here we provide a comprehensive overview of the endocrine and reproductive profile in boys and young male adults born after ICSI using ejaculated spermatozoa alleviating male factor infertility in their parents.

RECENT FINDINGS

Levels of testosterone, anti-Müllerian hormone and inhibin B were found comparable in prepubertal and pubertal boys conceived by ICSI when compared with levels in boys conceived spontaneously. Also, at young adulthood, mean levels of reproductive hormones did not differ from control peers. However, semen analysis showed significantly lower sperm concentration, total sperm count and total motile sperm count when compared with controls. Furthermore, the risk of having sperm concentration and sperm count below the reference values was increased in ICSI offspring while sperm parameters did not correlate in paired father-son semen analysis.

SUMMARY

Although endocrine gonadal function was normal at puberty, exocrine function at young adulthood was not. We observed decreased semen quality and quantity in young adults conceived by ICSI performed to circumvent male factor infertility. The possibility of transgenerational transmission of impaired spermatogenesis after ICSI needs further investigation.

Male infertility: establishing sperm aneuploidy thresholds in the laboratory

PURPOSE

Fluorescence in situ hybridization (FISH) in spermatozoa provides an estimate of the frequency of chromosomal abnormalities, but there is not a clinical consensus on how to statistically analyze sperm FISH results. We therefore propose a statistical approach to establish sperm aneuploidy thresholds in a fertile population.

METHODS

We have determined the distribution and variation of the frequency of nullisomy, disomy, and diploidy for a set of 13 chromosomes (1, 2, 9, 13, 15, 16, 17, 18, 19, 21, 22, X, and Y) in sperm nuclei from 14 fertile men by means of automatized FISH. The dispersion of data has been analyzed by the non-parametric Wilcoxon Rank Sum test. We have established the threshold values for each chromosome and aneuploidy type on the basis of the confidence interval values (99.9%).

RESULTS

Nullisomy thresholds ranged from 0.49% for chromosome 19 to 3.09% for chromosome 22; disomy thresholds ranged from 0.30% for chromosome 21 to 1.47% for chromosome 15; diploidy thresholds ranged from 0.24% for the 9/19 chromosome set to 1.21% for the 13/21 chromosome set.

CONCLUSIONS

Applying this approach with clinical purposes will enable us to categorize the patient as altered or normal regarding his sperm aneuploidy. Any result surpassing the cited threshold values indicates a 99.9% probability of being significantly different from fertile controls.

Risk of stillbirth in low-risk singleton term pregnancies following fertility treatment: a national cohort study

OBJECTIVE

To assess the risk of stillbirth in low-risk in vitro fertilisation (IVF) pregnancies.

DESIGN

Register-based national cohort study.

SETTING

Denmark 2003-2013.

POPULATION

Cohort of 425 732 singleton pregnancies including 10 235 conceived following IVF/intracytoplasmic sperm injection (ICSI), 4521 conceived following intrauterine insemination (IUI), and 410 976 spontaneously conceived.

METHODS

Information on pregnancy, obstetrical risk factors, stillbirth, and fertility treatment was obtained from the Danish national health registers for all pregnancies after gestational week 21⁺⁶ . We estimated the overall and gestational age-specific risk of stillbirth in low-risk term pregnancies following IVF, ICSI, and IUI. Further, we estimated the association between stillbirth and IVF and ICSI respectively as well as fresh or frozen-thawed embryo transfer.

MAIN OUTCOME MEASURES

Risk of stillbirth.

RESULTS

The number of stillbirths in spontaneously conceived and IVF/ICSI low-risk term pregnancies was 525 (0.1%) and 35 (0.3%), respectively. In multivariate analysis, the risk of stillbirth in pregnancies following IVF/ICSI was increased (odds ratio 2.1, 95% CI 1.4-3.1). The risk of stillbirth was correspondingly increased in time-to-event analyses taking risk time for each fetus into account from gestational week 37 and onwards (hazard ratio 2.4, 95% CI 1.6-3.6). In sub-analyses, the risk of stillbirth was increased for pregnancies following ICSI (odds ratio 2.2, 95% CI 1.2-3.1), but not IVF (odds ratio 1.7, 95% CI 0.9-3.1).

CONCLUSION

We found a systematically increased risk of stillbirth in low-risk term pregnancies following IVF/ICSI. Whether the risk was related to the treatment or to underlying subfertility is uncertain. The results may indicate a need for obstetrical surveillance for these pregnancies when reaching term.

TWEETABLE ABSTRACT

Increased risk of stillbirth in low-risk term pregnancies following fresh cycle IVF/ICSI.

Pregnancy and Neonatal Outcomes in Azoospermic Men After Intracytoplasmic Sperm Injection Using Testicular Sperm and Donor Sperm

Background

The safety of intracytoplasmic sperm injection (ICSI) with testicular sperm in azoospermic men has been a concern. We evaluated ICSI outcomes, including neonatal outcomes, in children born using testicular sperm or donor sperm.

Material/Methods

Ninety-nine males with nonobstructive azoospermia (NOA) who underwent microdissection testicular sperm extraction (micro-TESE) and 126 males with obstructive azoospermia (OA) were included in this study. Sixty-one patients with NOA used donor sperm for ICSI on the day of oocyte retrieval when no spermatozoa were identified by micro-TESE on the day before oocyte retrieval. ICSI outcomes were compared among OA, donor, and NOA groups.

Results

There was no statistical difference in terms of female partner characteristics among OA, donor, and NOA groups. The normal fertilization rate (P=0.005), high quality embryo rate (P=0.014), implantation rate (P<0.001), clinical pregnancy rate (P=0.015), live birth rate (P=0.043) were significant lower in the NOA group, compared with the donor sperm group. The normal fertilization rate was significant lower in the NOA group than the OA group (P<0.001), but the live birth rate was not significantly lower (P=0.058). The high-quality embryo rate (P=0.014) and implantation rate (P=0.009) were lower in the OA group than the donor group. No differences between groups were observed in our study regarding neonatal parameters of the infants born.

Conclusions

The fertilization and pregnancy outcomes were negatively affected by using testicular sperm from males with NOA. Once a live birth was achieved, there was no difference in neonatal outcomes.

High percentages of embryos with 21, 18 or 13 trisomy are related to advanced paternal age in donor egg cycles

OBJECTIVE

Advanced paternal age is related to poor sperm quality; however, little is known on its effect on aneuploidy embryo rates and, more importantly, on chromosomal abnormalities like trisomy 21, 18 and 13. The objective of this study was to evaluate the effect of advanced paternal age on the trisomy rates of the chromosomes 21, 18 or 13 in embryos obtained from donated oocytes.

METHODS

A total of 378 embryos, obtained from 52 IVF/ICSI cycles with donated oocytes in conjunction with PGD, were allocated according to paternal age in three groups: Group A: ≤39 years (n=115 embryos), Group B: 40-49 years (n=157 embryos) and Group C: ≥50 year (n=106 embryos). Fertilization rates, embryo quality at day 3, blastocysts development, and aneuploidy embryo rates were then compared.

RESULTS

There was no difference in seminal parameters (volume, concentration and motility) in the studied groups. Fertilization rate, percentages of zygotes that underwent cleavage, and good-quality embryos on Day 3 were similar between the three groups evaluated. The group of men ≥50 years had significantly more sperm with damaged DNA, higher global aneuploidy rates, and significantly more embryos with trisomy 21, 18 or 13 compared to the other two evaluated groups (p<0.05).

CONCLUSIONS

Our data shows that advanced paternal age increases global chromosomal abnormalities, and percentages of trisomy 21, 18 or 13 in embryos, and such effect is significantly important as of the age of 50. Embryo genetic screening is highly recommended in patients in which paternal age is ≥50 years old.

Mechanisms of Aneuploidy in Human Eggs

Eggs and sperm develop through a specialized cell division called meiosis. During meiosis, the number of chromosomes is reduced by two sequential divisions in preparation for fertilization. In human female meiosis, chromosomes frequently segregate incorrectly, resulting in eggs with an abnormal number of chromosomes. When fertilized, these eggs give rise to aneuploid embryos that usually fail to develop. As women become older, errors in meiosis occur more frequently, resulting in increased risks of infertility, miscarriage, and congenital syndromes, such as Down's syndrome. Here, we review recent studies that identify the mechanisms causing aneuploidy in female meiosis, with a particular emphasis on studies in humans.

Aneuploidy: a common and early evidence-based biomarker for carcinogens and reproductive toxicants

Aneuploidy, defined as structural and numerical aberrations of chromosomes, continues to draw attention as an informative effect biomarker for carcinogens and male reproductive toxicants. It has been well documented that aneuploidy is a hallmark of cancer. Aneuploidies in oocytes and spermatozoa contribute to infertility, pregnancy loss and a number of congenital abnormalities, and sperm aneuploidy is associated with testicular cancer. It is striking that several carcinogens induce aneuploidy in somatic cells, and also adversely affect the chromosome compliment of germ cells. In this paper we review 1) the contributions of aneuploidy to cancer, infertility, and developmental abnormalities; 2) techniques for assessing aneuploidy in precancerous and malignant lesions and in sperm; and 3) the utility of aneuploidy as a biomarker for integrated chemical assessments of carcinogenicity, and reproductive and developmental toxicity.

Physiological Aspects of Female Fertility: Role of the Environment, Modern Lifestyle, and Genetics

Across the Western World there is an increasing trend to postpone childbearing. Consequently, the negative influence of age on oocyte quality may lead to a difficulty in conceiving for many couples. Furthermore, lifestyle factors may exacerbate a couple's difficulty in conceiving due mainly to the metabolic influence of obesity; however, the negative impacts of low peripheral body fat, excessive exercise, the increasing prevalence of sexually transmitted diseases, and smoking all have significant negative effects on fertility. Other factors that impede conception are the perceived increasing prevalence of the polycystic ovary syndrome, which is further exacerbated by obesity, and the presence of uterine fibroids and endometriosis (a progressive pelvic inflammatory disorder) which are more prevalent in older women. A tendency for an earlier sexual debut and to have more sexual partners has led to an increase in sexually transmitted diseases. In addition, there are several genetic influences that may limit the number of oocytes within the ovary; consequently, by postponing attempts at childbearing, a limitation of oocyte number may become evident, whereas in previous generations with earlier conception this potentially reduced reproductive life span did not manifest in infertility. Environmental influences on reproduction are under increasing scrutiny. Although firm evidence is lacking however, dioxin exposure may be linked to endometriosis, phthalate exposure may influence ovarian reserve, and bisphenol A may interfere with oocyte development and maturation. However, chemotherapy or radiotherapy is recognized to lead to ovarian damage and predispose the woman to ovarian failure.

Preimplantation genetic testing: polar bodies, blastomeres, trophectoderm cells, or blastocoelic fluid?

OBJECTIVE

To investigate the blastocoelic fluid (BF) for the presence of DNA that could be amplified and analyzed; the extent to which its chromosomal status corresponds to that found in trophectoderm (TE) cells, polar bodies (PBs), or blastomeres; and the identification of segmental abnormalities.

DESIGN

Longitudinal cohort study.

SETTING

In vitro fertilization unit.

PATIENT(S)

Fifty-one couples undergoing preimplantation genetic screening or preimplantation genetic diagnosis for translocations by array-comparative genomic hybridization on PBs (n = 21) or blastomeres (n = 30).

INTERVENTION(S)

BFs and TE cells were retrieved from 116 blastocysts, whose chromosome status had already been established by PB or blastomere assessment. Separate chromosome analysis was performed in 70 BFs.

MAIN OUTCOME MEASURE(S)

Presence of DNA in BFs, evaluation of the chromosome condition, and comparison with the diagnosis made in TE cells and at earlier stage biopsies.

RESULT(S)

DNA detection was 82%, with a net improvement after refinement of the procedure. In 97.1% of BFs, the ploidy condition corresponded to that found in TE cells, with one false positive and one false negative. The rate of concordance per single chromosome was 98.4%. Ploidy and chromosome concordance with PBs were 94% and 97.9%, respectively; with blastomeres, the concordances were 95% and 97.7%, respectively. Segmental abnormalities, which were detected in PBs or blastomeres of 16 blastocysts, were also identified in the corresponding BFs.

CONCLUSION(S)

BF represents to a good extent the blastocyst ploidy condition and chromosome status when compared with TE cells. If the proportion of clinically useful BFs is improved, blastocentesis could become the preferred source of DNA for chromosomal testing.

The IMSI Procedure Improves Laboratory and Clinical Outcomes Without Compromising the Aneuploidy Rate When Compared to the Classical ICSI Procedure

PURPOSE

The intracytoplasmic morphologically selected sperm injection (IMSI) procedure has been associated with better laboratory and clinical outcomes in assisted reproduction technologies. Less information is available regarding the relationship between embryo aneuploidy rate and the IMSI procedure. The aim of this study is to compare the clinical outcomes and chromosomal status of IMSI-derived embryos with those obtained from intracytoplasmic sperm injection (ICSI) in order to establish a clearer view of the benefits of IMSI in infertile patients.

METHODS

We retrospectively analyzed a total of 11 cycles of IMSI and 20 cycles of ICSI with preimplantation genetic diagnosis. The fertilization rate, cleavage rate, embryo quality, blastocyst development, aneuploidy rate, pregnancy rate, implantation rate, and miscarriage rate were compared between the groups.

RESULTS

Similar rates of fertilization (70% and 73%), cleavage (98% and 100%), and aneuploidy (76.9% and 70.9%) were observed in the IMSI and ICSI groups, respectively. The IMSI group had significantly more good quality embryos at day 3 (95% vs 73%), higher blastocyst development rates (33% vs 19%), and greater number of hatching blastocysts (43% vs 28%), cycles with at least one blastocyst at day 5 (55% vs 35%), and blastocysts with good trophoectoderm morphology (21% vs 6%) compared with the ICSI group (P < 0.001). Significantly higher implantation rates were observed in the IMSI group compared with the ICSI group (57% vs 27%; P < 0.05). Pregnancy and miscarriage rates were similar in both groups (80% vs 50% and 0% vs 33%, respectively).

CONCLUSION

The IMSI procedure significantly improves the embryo quality/development by increasing the implantation rates without affecting the chromosomal status of embryos. There is a tendency for the IMSI procedure to enhance the pregnancy rates and lower the miscarriage rates when compared with ICSI.

High Aneuploidy Rates Observed in Embryos Derived from Donated Oocytes are Related to Male Aging and High Percentages of Sperm DNA Fragmentation

CAPSULE

Male aging effects on aneuploidy rates in embryos.

OBJECTIVE

Paternal age is associated with decreasing sperm quality; however, it is unknown if it influences chromosomal abnormalities in embryos. The objective of this study is to evaluate if the aneuploidy rates in embryos are affected by advanced paternal age.

METHODS

A total of 286 embryos, obtained from 32 in vitro fertilization/intracytoplasmic sperm injection cycles with donated oocytes in conjunction with preimplantation genetic diagnosis, were allocated according to paternal age in three groups: Group A: ≤39 years (n = 44 embryos); Group B: 40-49 years (n = 154 embryos); and Group C: ≥50 years (n = 88 embryos). Fertilization rates, embryo quality at day 3, blastocyst development, and aneuploidy embryo rates were then compared.

RESULTS

There was no difference in the seminal parameters (volume, concentration, and motility) in the studied groups. Fertilization rate, percentages of zygotes underwent cleavage, and good quality embryos on day 3 were similar between the three evaluated groups. The group of men ≥50 years had significantly more sperm with damaged DNA, low blastocyst development rate, and higher aneuploidy rates in embryos compared to the other two evaluated groups (P < 0.05).

CONCLUSIONS

Our findings suggest that advanced paternal age increases the aneuploidy rates in embryos from donated oocytes, which suggests that genetic screening is necessary in those egg donor cycles with sperm from patients >50 years old.

Influence of sperm fertilising concentration, sperm selection method and sperm capacitation procedure on the incidence of numerical chromosomal abnormalities in IVF early bovine embryos

The occurrence of numerical chromosomal aberrations, widely described as a major cause of mortality in in vitro-produced (IVP) embryos, has been linked to several factors. In the present study we investigated the effect of sperm fertilising concentration and semen handling (sperm selection and capacitation) before IVF on the rate of numerical chromosomal abnormalities in bovine embryos. In all, 466 IVP cattle embryos were karyotyped throughout three sequential experiments, analysing the effects of sperm fertilising concentration (0.1, 1.0 or 10×10(6) spermatozoa mL(-1)), selection method (unselected or Percoll-selected spermatozoa) and capacitation medium (bovine serum albumin (BSA), heparin or their combination). The percentage of normal (diploid) and aberrant (haploid, polyploid or aneuploid) embryos was noted in each experiment. The rate of numerical chromosomal abnormalities was mainly affected by sperm fertilising concentration (P<0.01) and, to a lesser extent, by the sperm capacitation medium (P<0.05). Polyploidy and haploidy rates were only affected by sperm fertilising concentration (P<0.05). Interestingly, the sperm selection technique used in the present study did not reduce the incidence of chromosome abnormalities in IVP cattle embryos (P>0.05). Finally, aneuploidy rates were not affected during the experiments (P>0.05), which suggests that they are not related to sperm-related factors. On the basis of these results, we conclude that sperm fertilising concentration is the 'paternal' key factor that affects the rate of numerical chromosomal abnormalities in IVP bovine embryos. By making small adjustments to fertilising protocols, the rate of cytogenetically aberrant embryos can be markedly reduced.

Impact of sperm genome decay on Day-3 embryo chromosomal abnormalities from advanced-maternal-age patients

Infertile male patients often exhibit unconventional semen parameters, including DNA fragmentation, chromatin dispersion, and aneuploidy-collectively referred to as sperm genome decay (SGD). We investigated the correlation of SGD to embryo chromosomal abnormalities and its effect on clinical pregnancy rates in patients with advanced maternal age (AMA) (>40 years) who were undergoing intracytoplasmic sperm injection-preimplantation genetic screening (ICSI-PGS). Three groups were assessed: patients with AMA and male partners with normal sperm (AMA-N); AMA patients and male partners presenting with SGD (AMA-SGD); and young fertile female patients and male partners with SGD (Y-SGD). We found a significant increase in embryonic chromosomal abnormalities-polyploidy, nullisomy, mosaicism, and chaotic anomaly rates-when semen parameters are altered (76% vs. 67% and 66% in AMA-SGD vs. AMA-N and Y-SGD groups, respectively). Statistical analysis showed a correlation between SGD and aneuploidies of embryonic chromosomes 13, 16, 21, X, and Y, as well as negative clinical outcomes. Incorporation of molecular sperm analyses should therefore significantly minimize the risk of transmission of chromosomal anomalies from spermatozoa to embryos, and may provide better predictors of pregnancy than conventional sperm analyses. We also demonstrated that an ICSI-PGS program should be implemented for SGD patients in order to limit transmission of chromosomal paternal anomalies and to improve clinical outcome.

New tools for embryo selection: comprehensive chromosome screening by array comparative genomic hybridization

The objective of this study was to evaluate the usefulness of comprehensive chromosome screening (CCS) using array comparative genomic hybridization (aCGH). The study included 1420 CCS cycles for recurrent miscarriage (n = 203); repetitive implantation failure (n = 188); severe male factor (n = 116); previous trisomic pregnancy (n = 33); and advanced maternal age (n = 880). CCS was performed in cycles with fresh oocytes and embryos (n = 774); mixed cycles with fresh and vitrified oocytes (n = 320); mixed cycles with fresh and vitrified day-2 embryos (n = 235); and mixed cycles with fresh and vitrified day-3 embryos (n = 91). Day-3 embryo biopsy was performed and analyzed by aCGH followed by day-5 embryo transfer. Consistent implantation (range: 40.5–54.2%) and pregnancy rates per transfer (range: 46.0–62.9%) were obtained for all the indications and independently of the origin of the oocytes or embryos. However, a lower delivery rate per cycle was achieved in women aged over 40 years (18.1%) due to the higher percentage of aneuploid embryos (85.3%) and lower number of cycles with at least one euploid embryo available per transfer (40.3%). We concluded that aneuploidy is one of the major factors which affect embryo implantation.

The origin, mechanisms, incidence and clinical consequences of chromosomal mosaicism in humans

BACKGROUND

Chromosomal mosaicism, the presence of two or more distinct cell lines, is prevalent throughout human pre- and post-implantation development and can lead to genetic abnormalities, miscarriages, stillbirths or live births. Due to the prevalence and significance of mosaicism in the human species, it is important to understand the origins, mechanisms and incidence of mosaicism throughout development.

METHODS

Literature searches were conducted utilizing Pubmed, with emphasis on human pre- and post-implantation mosaicism.

RESULTS

Mosaicism persists in two separate forms: general and confined. General mosaicism is routine during human embryonic growth as detected by preimplantation genetic screening at either the cleavage or blastocyst stage, leading to mosaicism within both the placenta and fetus proper. Confined mosaicism has been reported in the brain, gonads and placenta, amongst other places. Mosaicism is derived from a variety of mechanisms including chromosome non-disjunction, anaphase lagging or endoreplication. Anaphase lagging has been implicated as the main process by which mosaicism arises in the preimplantation embryo. Furthermore, mosaicism can be caused by any one of numerous factors from paternal, maternal or exogenous factors such as culture media or possibly controlled ovarian hyperstimulation during in vitro fertilization (IVF). Mosaicism has been reported in as high as 70 and 90% of cleavage- and blastocyst-stage embryos derived from IVF, respectively.

CONCLUSIONS

The clinical consequences of mosaicism depend on which chromosome is involved, and when and where an error occurs. Mitotic rescue of a meiotic error or a very early mitotic error will typically lead to general mosaicism while a mitotic error at a specific cell lineage point typically leads to confined mosaicism. The clinical consequences of mosaicism are dependent on numerous aspects, with the consequences being unique for each event.

[Preimplantation diagnosis--PID: preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS)]

Preimplantation diagnosis (PID) comprises all the relevant diagnostic procedures for the investigation of genetic, structural, or numerical changes of the genetic information in spermatozoa and oocytes as well as in embryos after in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). PID of oocytes is well established in Germany for the above-mentioned indications. PID at the embryonic level, i.e., trophectoderm biopsy of blastocysts, is possible in centers with proven expertise in reproductive medicine and human genetics. A high risk for genetic disease in the child or a high likelihood for stillbirth or miscarriage is a prerequisite for PID. A specialized ethics committee is required to look into each case before making a decision. While PID is still under development in Germany, it has been a well-established technology worldwide for 24 years. International experience in PID and the resulting implications are discussed in this article.

Assisted reproduction and child neurodevelopmental outcomes: a systematic review

OBJECTIVE

To systematically review the existing literature on neurodevelopmental outcomes in children born after medically assisted reproduction compared with those of children born after spontaneous conception.

DESIGN

Systematic review.

SETTING

Not applicable.

PATIENT(S)

Children born after medically assisted reproduction vs. reference groups of spontaneously conceived children.

INTERVENTION(S)

Data were reviewed from worldwide published articles, without restrictions as to publication year or language. A total of 80 studies included between 31 and 2,446,044 children.

MAIN OUTCOME MEASURE(S)

Child neurodevelopmental outcomes categorized as cognitive, behavioral, emotional or psychomotor development, or diagnoses of mental disorders.

RESULT(S)

For infants, studies on psychomotor development showed no deficits, but few investigated cognitive or behavioral development. Studies on toddlers generally reported normal cognitive, behavioral, socio-emotional, and psychomotor development. For children in middle childhood, development seems comparable in children born after assisted reproduction and controls, although fewer studies have been conducted with follow-up to this age. Very few studies have assessed neurodevelopmental outcomes among teens, and the results are inconclusive. Studies investigating the risk of diagnoses of mental disorders are generally large, with long follow-up, but the results are inconsistent.

CONCLUSION(S)

It may tentatively be concluded that the neurodevelopment of children born after fertility treatment is overall comparable to that in children born after spontaneous conception.

Normal birth following PGD for reciprocal translocation after serial vitrification of oocytes from a poor responder: a case report

This case study reports the first successful birth outcome following preimplantation genetic diagnosis (PGD) for a chromosome translocation in embryos generated by serial vitrification of oocytes. A couple presented to the fertility clinic with 2 years of primary infertility. The woman was diagnosed with poor ovarian reserve and her partner was diagnosed with severe oligoteratozoospermia and the reciprocal translocation 46,XY,t(1;7)(p36.1;q11.23). Following counselling, the couple opted for serial vitrification of oocytes followed by PGD. A total of 31 oocytes were obtained in five egg collection cycles over a period of 12 months and 27 metaphase-II oocytes were vitrified. Nineteen of the 27 vitrified oocytes survived warming: 14 oocytes from the vitrified group and three oocytes from the fresh cycle were fertilized by intracytoplasmic sperm injection. Eleven embryos, including three from the fresh cycle, were biopsied on day 3 post insemination. Fluorescence in-situ hybridization was performed for the specific chromosomes involved in translocation. Only two embryos from the cryopreservation cycles were diagnosed as normal/balanced, one of which was transferred on day 5 post insemination. A normal healthy female infant was born at week 42 of gestation.