Chromosomal abnormalities in azoospermic and non-azoospermic infertile men: numbers needed to be screened to prevent adverse pregnancy outcomes

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.

Fertility problems in males carrying an inversion of chromosome 10

Chromosomal inversion is closely related to male infertility. Inversion carriers may produce abnormal gametes, which may lead to partial duplication/deletion of the embryonic chromosome and result in spontaneous abortion, a fetus with multiple anomalies, or birth of a malformed child. Genetic counselling remains challenging for these carriers in clinical practice. We report two male carriers with inversion of chromosome 10 and review 26 reported cases. In the first case, 46,XX,inv(10)(p13q22) of the fetal chromosome was found in prenatal diagnosis; this was inherited from the paternal side with 46XY,inv(10)(p13q22). Another case was a male carrier with inv(10)(q21.2q22.1). There have been 25 (89.3%) cases of pericentric inversion and three (10.7%) cases of paracentric inversion involving chromosome 10. Of 28 cases, nine were associated with pregestational infertility of the couples, while the other 19 cases were associated with gestational infertility of the couples or normozoospermia. The breakpoints at 10p15, 10p11, 10q11, and 10q21 were associated with pregestational infertility of the couples. The breakpoints at 10p15, 10p14, 10p13, 10p12, 10p11, 10q11, 10q21, 10q22, 10q23, 10q24, 10q25, and 10q26 were related to gestational infertility of the couples or normozoospermia. Although there is a high risk of infertility or recurrent miscarriages, carriers with inversion of chromosome 10 might produce healthy offspring. Natural pregnancy can be used as a choice for inversion carriers with recurrent spontaneous abortion.

Pericentric inversion in chromosome 1 and male infertility

Pericentric inversion in chromosome 1 was thought to cause male infertility through spermatogenic impairment, regardless of the breakpoint position. However, carriers of pericentric inversion in chromosome 1 have been reported with normal fertility and familial transmission. Here, we report two cases of pericentric inversion in chromosome 1. One case was detected in utero via amniocentesis, and the other case was detected after the wife of the carrier experienced two spontaneous abortions within 5 years of marriage. Here, the effect of the breakpoint position of the inversion in chromosome 1 on male infertility is examined and compared with the published cases. The association between the breakpoint of pericentric inversion in chromosome 1 and spermatogenesis is also discussed. Overall, the results suggest that the breakpoint position deserves attention from physicians in genetic counseling as inversion carriers can produce offspring.

Clinical Features of Infertile Men Carrying a Chromosome 9 Translocation

Previous studies indicated that chromosome 9 translocations are involved in reduced male fertility and increased chance of miscarriage in the female partner. The aim of this study was to review the clinical features and genetic counselling requirements of infertile men carrying chromosome 9 translocations. This study analyzed fertile-age male carriers of chromosome 9 translocations, and included 12 clinical cases in our hospital. In our cases, three cases had oligozoospermia or severe oligozoospermia, while nine cases had normal semen. Of the latter nine cases, seven were associated with recurrent spontaneous abortions, and two produced a phenotypically normal child as confirmed by amniocentesis. Male chromosome 9 translocations and specific breakpoints from reported papers were searched using PubMed and CNKI database. A literature review identified 76 male patients who carried chromosome 9 translocations. Breakpoints at 9p12, 9p11, 9p10 and 9q34.1 were related to pregestational infertility, while breakpoints at 9p21, 9q10, 9q11, 9q13, 9q21.1, 9q22, 9q22.2, 9q22.3, 9q34, 9q34.2 and 9q34.3 exhibited gestational infertility. Chromosome translocations involving chromosome 9 lead to increased risk of miscarriage. Carriers of chromosome 9 translocations should be counselled to consider in vitro fertilization accompanied by preimplantation genetic diagnosis.

Chromosomal abnormalities in 1663 infertile men with azoospermia: the clinical consequences

STUDY QUESTION

What is the prevalence of chromosomal abnormalities in azoospermic men and what are the clinical consequences in terms of increased risk for absent spermatogenesis, miscarriages and offspring with congenital malformations?

SUMMARY ANSWER

The prevalence of chromosomal abnormalities in azoospermia was 14.4%, and the number of azoospermic men needed to be screened (NNS) to identify one man with a chromosomal abnormality with increased risk for absence of spermatogenesis was 72, to prevent one miscarriage 370-739 and to prevent one child with congenital malformations 4751-23 757.

WHAT IS KNOWN ALREADY

Infertility guidelines worldwide advise screening of non-iatrogenic azoospermic men for chromosomal abnormalities, but only few data are available on the clinical consequences of this screening strategy.

STUDY DESIGN, SIZE, DURATION

This retrospective multicentre cross-sectional study of non-iatrogenic azoospermic men was performed at the University Hospital Brussels, Belgium, and the University Medical Centre Groningen, The Netherlands, between January 2000 and July 2016.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Analysis of clinical registries retrospectively identified 1663 non-iatrogenic azoospermic men with available results of karyotyping and FSH serum levels. Iatrogenic azoospermia was an exclusion criterion, defined as azoospermia after spermatotoxic medical treatment, exogenous androgen suppletion or vasectomy and/or vasovasostomy. Also, men with a clinical diagnosis of anejaculation or hypogonadotropic hypo-androgenism and/or FSH values <1.0 U/l were excluded. Chromosomal abnormalities were categorized according to their (theoretical) impact on clinical consequences for the patient (i.e. an increased risk for absence of spermatogenesis) and adverse pregnancy outcomes (i.e. miscarriage or offspring with congenital malformations), in both normogonadotropic (FSH < 10 U/l) and hypergonadotropic (FSH ≥ 10 U/l) azoospermia. We estimated the NNS for chromosomal abnormalities to identify one man with absence of spermatogenesis and to prevent one miscarriage or one child with congenital malformations, and calculated the surgical sperm retrieval rates per chromosomal abnormality.

MAIN RESULTS AND THE ROLE OF CHANCE

The overall prevalence of chromosomal abnormalities in azoospermia was 14.4% (95% CI 12.7-16.1%), its prevalence being higher in hypergonadotropic azoospermia (20.2%, 95% CI 17.8-22.7%) compared to normogonadotropic azoospermia (4.9%, 95% CI 3.2-6.6%, P < 0.001). Klinefelter syndrome accounted for 83% (95% CI 77-87%) of abnormalities in hypergonadotropic azoospermia. The NNS to identify one man with increased risk for absence of spermatogenesis was 72, to prevent one miscarriage 370-739, and to prevent one child with congenital malformations 4751-23 757. There was no clinically significant difference in NNS between men with normogonadotropic and hypergonadotropic azoospermia. The surgical sperm retrieval rate was significantly higher in azoospermic men with a normal karyotype (60%, 95% CI 57.7-63.1%) compared to men with a chromosomal abnormality (32%, 95% CI 25.9-39.0%, P < 0.001). The sperm retrieval rate in Klinefelter syndrome was 28% (95% CI 20.7-35.0%).

LIMITATIONS, REASONS FOR CAUTION

The absolute number of chromosomal abnormalities associated with clinical consequences and adverse pregnancy outcomes in our study was limited, thereby increasing the role of chance. Further, as there are currently no large series on outcomes of pregnancies in men with chromosomal abnormalities, our conclusions are partly based on assumptions derived from the literature.

WIDER IMPLICATIONS OF THE FINDINGS

The NNS found can be used in future cost-effectiveness studies and the evaluation of current guidelines on karyotyping in non-iatrogenic azoospermia.

STUDY FUNDING/COMPETING INTEREST(S)

None to declare.

Clinical features of carriers of reciprocal chromosomal translocations involving chromosome 2: report of nine cases and review of the literature

OBJECTIVE

To explore the clinical features of carriers of chromosome 2 translocations, enabling informed genetic counseling of these patients.

MATERIALS AND METHODS

Eighty-two male carriers of a translocation who were infertile or receiving fertility counseling were recruited. Cytogenetic analyses were performed using G-banding. A search of PubMed was performed to determine whether the identified translocations on chromosome 2 are involved in male infertility. The relationships of translocation breakpoints with male infertility and recurrent pregnancy loss were analyzed.

RESULTS

Of the 82 translocation carriers, 9 (11%) were carriers of a chromosome 2 translocation. Four cases had oligozoospermia or infertility, while five had normal semen. In an analysis of the literature, 55 patients who were carriers of chromosome 2 translocations were also reviewed. Breakpoints at 2p13 and 2q31 were observed in six patients each, and were the most common. Breakpoints at 2p23, 2p13, 2p11.2, 2q31, and 2q37 were associated to both pre-gestational and gestational infertility, while other breakpoints were associated with gestational infertility.

CONCLUSIONS

All breakpoints at chromosome 2 were correlated with gestational infertility. Carriers of chromosome 2 translocations should therefore receive counseling to continue with natural conception and use of different technologies available via assisted reproductive technology, such as preimplantation genetic diagnosis.

A report of nine cases and review of the literature of infertile men carrying balanced translocations involving chromosome 5

Background

Balanced translocations may cause the loss of genetic material at the breakpoints and may result in failure of spermatogenesis. However, carriers of reciprocal translocation may naturally conceive. Genetic counseling of male carriers of translocations remains challenging. This study explores the clinical features of carriers of chromosome 5 translocations, enabling informed genetic counseling of these patients.

Results

Of 82 translocation carriers, 9 (11%) were carriers of a chromosome 5 translocation. One case had azoospermia, while three cases had experienced recurrent spontaneous abortions, two cases had each experienced stillbirth, and three cases produced a phenotypically normal child confirmed by amniocentesis. A literature review identified 106 patients who carried chromosome 5 translocations. The most common chromosome 5 translocation was t(4,5), observed in 13 patients. Breakpoint at 5p15 was observed in 11 patients. All breakpoints at chromosome 5 were associated with gestational infertility.

Conclusion

In genetic counseling, physicians should consider chromosome 5 and its breakpoints. Carriers of chromosome 5 translocations may continue with natural conception or use assisted reproductive technologies, such as preimplantation genetic diagnosis.

The diagnosis of male infertility: an analysis of the evidence to support the development of global WHO guidance-challenges and future research opportunities

BACKGROUND

Herein, we describe the consensus guideline methodology, summarize the evidence-based recommendations we provided to the World Health Organization (WHO) for their consideration in the development of global guidance and present a narrative review of the diagnosis of male infertility as related to the eight prioritized (problem or population (P), intervention (I), comparison (C) and outcome(s) (O) (PICO)) questions. Additionally, we discuss the challenges and research gaps identified during the synthesis of this evidence.

OBJECTIVE AND RATIONALE

The aim of this paper is to present an evidence-based approach for the diagnosis of male infertility as related to the eight prioritized PICO questions.

SEARCH METHODS

Collating the evidence to support providing recommendations involved a collaborative process as developed by WHO, namely: identification of priority questions and critical outcomes; retrieval of up-to-date evidence and existing guidelines; assessment and synthesis of the evidence; and the formulation of draft recommendations to be used for reaching consensus with a wide range of global stakeholders. For each draft recommendation the quality of the supporting evidence was then graded and assessed for consideration during a WHO consensus.

OUTCOMES

Evidence was synthesized and recommendations were drafted to address the diagnosis of male infertility specifically encompassing the following: What is the prevalence of male infertility and what proportion of infertility is attributable to the male? Is it necessary for all infertile men to undergo a thorough evaluation? What is the clinical (ART/non ART) value of traditional semen parameters? What key male lifestyle factors impact on fertility (focusing on obesity, heat and tobacco smoking)? Do supplementary oral antioxidants or herbal therapies significantly influence fertility outcomes for infertile men? What are the evidence-based criteria for genetic screening of infertile men? How does a history of neoplasia and related treatments in the male impact on (his and his partner's) reproductive health and fertility options? And lastly, what is the impact of varicocele on male fertility and does correction of varicocele improve semen parameters and/or fertility?

WIDER IMPLICATIONS

This evidence synthesis analysis has been conducted in a manner to be considered for global applicability for the diagnosis of male infertility.

Probing the effect of human normal sperm morphology rate on cycle outcomes and assisted reproductive methods selection

Sperm morphology is the best predictor of fertilization potential, and the critical predictive information for supporting assisted reproductive methods selection. Given its important predictive value and the declining reality of semen quality in recent years, the threshold of normal sperm morphology rate (NSMR) is being constantly corrected and controversial, from the 4^th edition (14%) to the 5^th version (4%). We retrospectively analyzed 4756 cases of infertility patients treated with conventional-IVF(c-IVF) or ICSI, which were divided into three groups according to NSMR: ≥14%, 4%–14% and <4%. Here, we demonstrate that, with decrease in NSMR(≥14%, 4%–14%, <4%), in the c-IVF group, the rate of fertilization, normal fertilization, high-quality embryo, multi-pregnancy and birth weight of twins gradually decreased significantly (P<0.05), while the miscarriage rate was significantly increased (p<0.01) and implantation rate, clinical pregnancy rate, ectopic pregnancy rate, preterm birth rate, live birth rate, sex ratio, and birth weight(Singleton) showed no significant change. In the ICSI group, with decrease in NSMR (≥14%, 4%–14%, <4%), high-quality embryo rate, multi-pregnancy rate and birth weight of twins were gradually decreased significantly (p<0.05), while other parameters had no significant difference. Considering the clinical assisted methods selection, in the NFMR ≥14% group, normal fertilization rate of c-IVF was significantly higher than the ICSI group (P<0.05), in the 4%–14% group, birth weight (twins) of c-IVF were significantly higher than the ICSI group, in the <4% group, miscarriage of IVF was significantly higher than the ICSI group. Therefore, we conclude that NSMR is positively related to embryo reproductive potential, and when NSMR<4% (5^th edition), ICSI should be considered first, while the NSMR≥4%, c-IVF assisted reproduction might be preferred.

Evidence-based management of recurrent miscarriages

Recurrent miscarriages are postimplantation failures in natural conception; they are also termed as habitual abortions or recurrent pregnancy losses. Recurrent pregnancy loss is disheartening to the couple and to the treating clinician. There has been a wide range of research from aetiology to management of recurrent pregnancy loss. It is one of the most debated topic among clinicians and academics. The ideal management is unanswered. This review is aimed to produce an evidence-based guidance on clinical management of recurrent miscarriage. The review is structured to be clinically relevant. We have searched electronic databases (PubMed and Embase) using different key words. We have combined the searches and arranged them with the hierarchy of evidences. We have critically appraised the evidence to produce a concise answer for clinical practice. We have graded the evidence from level I to V on which these recommendations are based.

Sperm flow cytometric parameters are associated with ICSI outcome

The association of sperm nuclear chromatin condensation and ploidy with embryo development and outcome after intracytoplasmic sperm injection (ICSI) was explored. The study population consisted of 16 couples referred to Ioannina University Medical School In vitro Fertilization Unit with male factor infertility and serious impairments in sperm nuclear chromatin condensation and ploidy, according to sperm flow cytometry. Additionally, 20 couples with male factor infertility and relatively high sperm flow cytometry parameters participated as controls. The 35 cycles of the study population were characterized by a lower fertilization rate (P<0.001) as well as decreased grade A embryo rate (P=0.004) and increased grade C embryo rate (P=0.028), compared with the 29 cycles of the control group. Additionally, a significantly elevated arrested embryo rate (P<0.001) and a decreased clinical pregnancy rate (P<0.020) were observed in the couples of the study population. Consequently, high levels of sperm nuclear chromatin condensation abnormalities and sperm aneuploidies are probably associated with lower fertilization rates, impaired embryo quality, elevated arrested embryo rates and decreased pregnancy rates. These preliminary results strongly support the use of sperm flow cytometry as a potential prognostic tool of ICSI outcome.