Does cryopreservation of sperm affect fertilization in nonobstructive azoospermia or cryptozoospermia?

Sperm cryopreservation does not affect live birth rate in normozoospermic men: analysis of 7969 oocyte donation cycles

STUDY QUESTION

Does sperm cryopreservation influence the reproductive outcomes of normozoospermic patients in oocyte donation cycles?

SUMMARY ANSWER

After controlling for confounders, the use of cryopreserved semen from normozoospermic patients does not affect pregnancy and live birth rates after elective ICSI.

WHAT IS KNOWN ALREADY

Sperm cryopreservation by slow freezing is a common practice in ART. While frozen-thawed semen typically presents reduced motility and vitality, its use for ICSI is generally considered adequate in terms of reproductive outcomes. Nevertheless, most studies comparing reproductive outcomes between fresh and cryopreserved sperm include patients with severe male factor (testicular sperm, oligo-, and/or asthenozoospermia) or women of advanced maternal age, where the altered quality of the gametes can partially mask the full effect of freezing/thawing.

STUDY DESIGN, SIZE, DURATION

The study included a retrospective cohort of 7969 couples undergoing their first oocyte donation cycle between January 2013 and December 2019 in one large clinic, using normozoospermic semen from the male partner. All cycles involved elective ICSI, fresh oocytes, and a fresh embryo transfer, either at cleavage or blastocyst stage. Two study groups were established based on the sperm status: fresh (n = 2865) and cryopreserved (n = 5104).

PARTICIPANTS/MATERIALS, SETTING, METHODS

A slow freezing protocol was used for all sperm cryopreservation. Sperm washing, capacitation, and selection prior to ICSI were performed identically for fresh and frozen-thawed samples, using pellet swim-up. Fertilization rate (FR), pregnancy (biochemical and ongoing), and live birth rates were compared between study groups using univariate and multivariate regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

Male and female age, sperm concentration and motility after ejaculation, and number of oocytes inseminated were similar between cycles using fresh or cryopreserved sperm. Analysis by Student's t-test did not indicate a significant difference in FR between fresh and cryopreserved sperm (P = 0.0591); however, after adjusting for confounders, this difference reached statistical significance: 74.65% FR for fresh (CI 95%: 73.92-75.38) versus 73.66% for cryopreserved sperm (CI 95%: 73.11-74.20), P = 0.0334. The adjusted regression analysis revealed higher odds of biochemical pregnancy when using fresh sperm (odds ratio (OR): 1.143, P = 0.0175), but no significant effects of sperm cryopreservation were observed for ongoing pregnancy (OR: 1.101, P = 0.0983) and live birth (OR: 1.082, P = 0.1805).

LIMITATIONS, REASONS FOR CAUTION

Caution should be exerted when extrapolating these results to different protocols for sperm cryopreservation and selection, or to IVM, advanced maternal age and classical IVF cycles, which were excluded from analysis. Owing to the retrospective nature of the study, some uncontrolled for variables may affect the results.

WIDER IMPLICATIONS OF THE FINDINGS

Sperm cryopreservation does not affect pregnancy and live birth rates in normozoospermic patients, and although it may lower FR s slightly, this would not be clinically relevant. In line with previous studies that included patients with an apparent male or female factor, sperm cryopreservation is a safe and convenient technique.

STUDY FUNDING/COMPETING INTEREST(S)

The study received no external funding and all authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Treatment progress of cryptozoospermia with Western Medicine and traditional Chinese medicine: A literature review

Background and Aims

Cryptozoospermia is an extreme oligozoospermia with an unsatisfactory treatment effect, with an incidence rate of approximately 8.73% in male infertility, whose effective solution has become the call of the times. Western Medicine has achieved certain effects through drugs, surgery, and assisted reproductive therapy, but this is still not ideal. Traditional Chinese medicine (TCM) has made many achievements in other disciplines; however, there is still a lack of evidence-based medical evidence to improve sperm production.

Methods

The relevant literatures from the China National Knowledge Internet (CNKI) and PubMed in the past 10 years were collected in this article, of which the mechanisms, advantages, or current controversies of various treatment methods of Western Medicine and TCM were analyzed, to find new treatment methods and research directions.

Results

With the development of modern science and technology, medical treatments for cryptozoospermia have become increasingly abundant; however, there is still no universally recognized unified and effective guiding plan. Although TCM has not been fully verified by evidence-based medicine, most TCM combined with Western Medicine can achieve unexpected results.

Conclusion

The combination of TCM and Western Medicine may become a bane for cryptozoospermia and bring good news to infertile men worldwide.

Clinical Outcomes and Live Birth Rate Resulted From Microdissection Testicular Sperm Extraction With ICSI-IVF in Non-Obstructive Azoospermia: A Single-Center Cohort Study

BACKGROUND

Most of data available in the literature reported the sperm retrieval rate and limited intracytoplasmic sperm injection (ICSI) results of microdissection testicular sperm extraction (micro-TESE) in non-obstructive azoospermia (NOA) patients with different etiologies. Unfortunately, there is currently a lack of comprehensive data to guide clinicians in conducting comprehensive consultations with NOA patients.

OBJECTIVES

To obtain more comprehensive evidence-based data and clinical outcomes for better consultation of NOA patients who opted to undergo micro-TESE combined with ICSI-IVF.

METHODS

It was a retrospective study involved 968 NOA patients underwent micro-TESE during January 2015 to December 2019. Embryological, clinical, and live birth outcomes were demonstrated comprehensively and three kinds of stratification analyses were performed based on ICSI-IVF cycles using frozen and fresh sperm, different etiologies of NOA and various amounts of sperm retrieved.

RESULTS

The sperm retrieval rate was 44.6%, and ICSI was performed in 299 couples leading to 150 clinical pregnancies and 140 live-birth deliveries. The clinical pregnancy rate (CPR) was 50.17%, and the cumulative live birth rate (LBR) was 46.82%, and the low birth defects rate was 1.43%. No significant difference was observed about cumulative LBR in frozen sperm group and fresh sperm group (47.5% vs 42.9%, P>0.05). NOA patients with AZFc microdeletions had the lowest rate of a high-score embryo on day 3 (4.4%, P<0.05) and the lowest cumulative LBR (19.4%, P<0.05). NOA patients with lower sperm count (having fewer than 20 sperms retrieved) had significantly lower cumulative LBR than those with higher sperm count (having more than 20 sperms retrieved) (28.1% vs 51.9%, P<0.05).

CONCLUSIONS

For those NOA patients who stepped in ICSI-IVF cycles, the cumulative LBR was 46.82%. No significant difference was indicated in the LBR between ICSI-IVF cycles using frozen or fresh testicular sperm. Compared to other etiologies, NOA caused by AZFc microdeletions have the poorest embryological and clinical outcomes. Patients with less testicular sperm retrieved have poorer embryological and clinical outcomes.

Comparison of fresh and frozen ejaculated spermatozoa in sibling oocyte recipient cycles

RESEARCH QUESTION

Do IVF and intracytoplasmic sperm injection cycles using fresh and frozen ejaculated spermatozoa result in similar pregnancy outcomes in couples with non-male factor infertility?

DESIGN

Retrospective cohort study; patients undergoing donor egg recipient cycles, in which oocytes from a single ovarian stimulation were split between two recipients, were reviewed. Two recipients of oocytes from a single donor were paired and categorized based on the type of ejaculated spermatozoa (fresh/frozen). Outcomes included delivery rate, implantation, pregnancy, pregnancy loss and fertilization rates.

RESULTS

Of the 408 patients who received oocytes from a split donor oocyte cycle, 45 pairs of patients used discrepant types of ejaculated spermatozoa and were included in the study. Fertilization rate: fresh (74.8%); frozen (68.6%) (P = 0.13). Pregnancy rate: fresh (76%); frozen (67%); delivery rate: fresh (69%); frozen (44%); implantation rate was significantly higher: fresh (64%); frozen (36%) (P = 0.04). Rate of pregnancy loss was significantly higher in the frozen group compared with the fresh group (33% versus 5.9%, P = 0.013). Adjusted odds for delivery was 67% lower in the frozen group (95% CI 0.12, 0.89). Adjusted odds of pregnancy (adjusted OR 0.67, 95% CI 0.20, 2.27) and implantation (adjusted OR 0.5, 95% CI 0.12, 2.12) were not significantly different between the frozen and fresh sperm groups.

CONCLUSION

In this model that controls for oocyte quality by using paired recipients from the same donor, frozen ejaculated spermatozoa resulted in lower delivery rates than those using fresh spermatozoa.

Fresh vs frozen testicular sperm for assisted reproductive technology in patients with non-obstructive azoospermia: A systematic review

Objective

: To review the debate about the routine use of cryopreserved testicular sperm for intracytoplasmic sperm injection (ICSI) from patients with non-obstructive azoospermia (NOA), as some authors suggest repeating sperm retrieval in such cases due to poorer ICSI results when frozen–thawed testicular sperm is used compared with fresh sperm.

Methods

: A systematic literature review was performed in August 2020 using the Medical Literature Analysis and Retrieval System Online (MEDLINE), Web of Science databases and the Excerpta Medica dataBASE (EMBASE), and we included 26 studies that were considered eligible for this systematic review.

Results

: In all, 1189 publications were screened and 26 articles were included in the systematic review. Three meta-analysis reviews were included and they all concluded that the use of fresh and frozen sperms for ICSI from patients with NOA showed comparable fertilisation and pregnancy rates.

Conclusion

: The use of frozen testicular sperm from men with NOA results in fertilisation and clinical pregnancy rates similar to those of fresh sperm. This may encourage fertility centres to use frozen testicular sperm samples, as this policy has certain advantages that would help with organising their workflow.

Abbreviations: CPR: clinical pregnancy rate; 2PN%: two pronuclei % fertilisation rate; ICSI: intracytoplasmic sperm injection; NOA: non-obstructive azoospermia; OA, obstructive azoospermia; SCO: Sertoli cell-only syndrome; (micro-)TESE: (microsurgical) testicular sperm extraction

Tissue and sperm handling before assisted reproductive technology (ART): A systematic review

Objective

: To explore the medical literature on techniques of tissue and sperm handling after surgical retrieval for intracytoplasmic sperm injection (ICSI).

Methods

: A search was performed in PubMed and Google Scholar databases, according to a modified Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) guideline, considering the studies investigating tissue handling and sperm selection techniques for ICSI.

Results

: Overall, 42 articles were included in this study, investigating sample handling, methods for sperm selection, and the use of chemical compounds to improve sperm motility and fertilisation rates.

Conclusion

: The ideal sperm handling method should provide a high sperm count, high vitality and appropriate sperm function, without side-effects. In this review the most common and useful techniques are described and the best combination strategies discussed in clinical scenarios.

Questioning the utility of round spermatid injections in men with non-obstructive azoospermia

BACKGROUND

Data on who among the infertile male population may benefit from round spermatid injections (ROSI) are lacking.

OBJECTIVE

To determine the probability of finding round spermatids suitable for ROSI in men with non-obstructive azoospermia (NOA) in whom no spermatozoa were retrieved at testicular sperm extraction.

MATERIALS AND METHODS

Four-hundred fifty-seven consecutive men with azoospermia underwent testicular sperm extraction. Clinical examination included age, secondary sexual characteristics, testicular size, reproductive hormone estimation, karyotyping, and Y chromosome microdeletion analyses. Histologic examination was performed, and histologic classification was determined by the most advanced spermatogenetic cell identified in the combined histologic and cytologic examination.

RESULTS

Of the 457 azoospermic men, 342 were diagnosed with NOA, and 148 (148/342, 43%) had mixed atrophy on histopathology and retrievable spermatozoa. No spermatozoa were found in 194/342 men with NOA (57%). Histopathology diagnosed 145/194 (75%) of them with Sertoli cell only, 45/194 (23%) with spermatocyte maturation arrest, and 4/194 (2%) with spermatid maturation arrest.

CONCLUSIONS

Histopathologically identified round spermatids without spermatozoa were rare in men with NOA. Only very few of them are likely to reap the benefits of ROSI, thus presenting the need to reconsider its actual clinical value.

Intra-Cytosplamic sperm injection outcomes with fresh and cryopreserved human epidydimal sperm from patients with obstructive azoospermia

Techniques for the cryopreservation of epididymal sperm was are widely used in clinical practice. However, given the unique characteristics of sperm from patients with obstructive azoospermia, epididymal sperm cryopreservation is more difficult because of low count and weak motility; therefore, conventional methods of sperm cryopreservation may not result in the best outcomes. We used the micro-straw method to store small quantities of sperm obtained from patients with severe oligozoospermia or azoospermia and achieved successful deliveries in the previous study. This retrospective study of ICSI cycles included the first ICSI cycles of fresh or frozen/thawed epididymal sperm that were performed in patients suffering from obstructive azoospermia who were admitted to the CITIC-Xiangya Hospital of Reproduction and Genetics of China from June 1, 2015 to June 31, 2019. A total of 2441 patients with obstructive azoospermia were divided according to the use of fresh (n = 2342) or frozen/thawed (n = 99) epididymal sperm. The results showed that the fertilisation rate was higher with fresh epididymal sperm than that with frozen/thawed epididymal sperm (85.14% vs. 79.26%, respectively; p = 0.000). However, the rates of embryo cleavage, high-quality embryos, clinical pregnancy, miscarriage, singletons and birth defect were similar between fresh and frozen/thawed epididymal sperm (98.28% vs. 99.13%, 60.34% vs. 57.29%, 67.90% vs. 70.51%, 8.12% vs. 10.91%, 57.76% vs. 49.09%, 1.59% vs. 1.45%respectively; p = 0.088, 0.109, 0.628, 0.462,0.203 and 0.686). In addition, the short-term cryostorage of small quantities of epididymal sperm did not affect clinical outcomes. The results indicated that in cases of obstructive azoospermia, cryostorage of small quantities epididymal sperm is a reliable option.

The impact of fresh and frozen testicular tissue quality on embryological and clinical outcomes

Our ability to predict the potential of testicular spermatozoa to support embryonic development is still limited. Although motility of testicular spermatozoa is associated with embryo development, the impact of morphology and the presence of spermatozoa in the testicular sample has not been previously researched. Moreover, while the majority of data indicate no effect of cryopreservation, there are studies reporting impaired clinical outcomes due to testicular cryopreservation. In a retrospective study, 118 ICSI-TESE cycles were analysed to study the impact of (a) total quality of testicular tissue, (b) testicular tissue cryopreservation and (c) presence/motility/morphology of testicular spermatozoa in fertilisation rate, embryonic development, clinical pregnancy (CPR), ongoing pregnancy (OPR) and live birth rate (LBR). Results showed that fertilisation rate was significantly affected by both total quality of testicular tissue (p < .05) and rare presence of spermatozoa (p < .01). Moreover, total tissue quality (p < .01), cryopreservation of low-quality samples (p < .01), absence of motile testicular spermatozoa (p < .01) and poor spermatozoa morphology (p < .05) had a negative impact on the number of good quality day 3 embryos. CPR, OPR or LBR was not affected by any parameters examined. Our data suggest that the quality of testicular tissue influences both fertilisation rate and embryo development. Moreover, cryopreservation of low-quality testicular samples has a negative impact on the number of available embryos for transfer.

Modified stepwise mini-incision microdissection testicular sperm extraction: a useful technique for patients with a history of orchidopexy affected by non-obstructive azoospermia

Non-obstructive azoospermia (NOA), which is defined as the absence of spermatozoa in the ejaculate secondary to impaired spermatogenesis within the testis, may be caused by a variety of etiologies, including varicocele-induced testicular damage, cryptorchidism, prior testicular torsion, post-pubertal mumps orchitis, gonadotoxic effects from medications, genetic abnormalities, chemotherapy/radiation, and other unknown causes currently classified as idiopathic (Cocuzza et al., 2013). The microdissection testicular sperm extraction (micro-TESE) technique involves a meticulous microsurgical exploration of the testicular parenchyma to identify and selectively extract larger seminiferous tubules that carry a higher probability of complete spermatogenesis (Schlegel, 1999). The Cornell group evaluated the efficacy of micro-TESE in 152 NOA patients with an associated history of cryptorchidism. In their series, spermatozoa were successfully retrieved in 116/181 attempts (64%), and the resulting pregnancy rate was 50% with a delivery rate of 38% (Dabaja and Schlegel, 2013). Franco et al. (2016) described a stepwise micro-TESE approach in NOA patients, which was considered to reduce the cost, time, and effort associated with the surgery. Alrabeeah et al. (2016) further reported that a mini-incision micro-TESE, carried through a 1-cm equatorial testicular incision, can be useful for micro-TESE candidates, particularly in patients with cryptozoospermia. We conducted a retrospective study of 20 consecutive NOA patients with a history of orchidopexy from May 2015 to March 2017.

Fertility outcome after Intracytoplasmic Sperm Injection with surgically retrieved sperm

BACKGROUND

Surgically retrieved sperm samples and Intra Cytoplasmic Sperm Injection are indicated when we face severe sperm abnormalities such as azoospermia. The objective of this study was to assess the rates of clinical pregnancies and live births with sperm from testicular biopsies.

DESIGN

This was a retrospective descriptive study of all Intra Cytoplasmic Sperm Injection (ICSI) cycles performed with surgically retrieved sperm at the Nîmes University Hospital from January 1st, 2015 to December 31st, 2018. The main outcome was the clinical pregnancy rate. The secondary outcomes were the fertilization rate, the implantation rate and the live birth rate.

RESULTS

In all, 99 couples were treated at our center during this period and 164 ICSI cycles using surgically-collected sperm were performed. The men were 34.7 ± 7.4 years old on average at the time of undergoing testicular biopsy and the women were 32.15 ± 5.07 years at the time of ICSI. Out of 127 fresh embryo transfers, we observed 47 clinical pregnancies (37 %) and 45 live births (35.4 %). The average fertilization rate was 45 % and the implantation rate was 23.7 %. Among these infertile couples, 53 % obtained at least one clinical pregnancy and 42 % at least one live birth.

CONCLUSION

Testicular sperm extraction combined with ICSI is indicated in cases of male infertility linked with azoospermia or severe semen alteration. This technique offers couples a marvelous opportunity to have children with their own gametes.

Male Infertility and the Future of In Vitro Fertilization

The male contribution to infertility has traditionally been overlooked, or at best oversimplified. In recent years efforts have been made to optimize diagnostic and therapeutic techniques to maximize fertility outcomes. A renewed focus on the male partner has resulted in an increased understanding of both genetic and epigenetic changes within the male germline. Furthermore, single-nucleotide polymorphisms, copy-number variants, DNA damage, sperm cryopreservation, obesity, and paternal age have recently been recognized as important factors that play a role in male fertility. Developing a deeper knowledge of these issues could potentially lead to improved success with assisted reproductive technology.

Sequential interval micro-droplet loading in closed hemi-straw carrier system: A convenient and efficient method for ultra-rapid cryopreservation in extreme oligozoospermia

Cryopreservation of human spermatozoa with low concentration while maintaining adequate post-thawing motility remains a major challenge for male fertility preservation. A convenient and efficient ultra-rapid freezing method for small amounts of human spermatozoa in a closed Hemi-Straw carrier system (CHS) was developed. Spermatozoa from 60 healthy men were involved in a parameter refining test and another 15 extreme oligozoospermic specimens were assigned to a verification test. A commercialized sperm freezing medium, Quinn's Advantage® Sperm Freeze medium (glycerol and sucrose as the cryoprotective agent) was used in the study. The results showed that the highest recovery rates would be obtained via the method of 2 μl single droplet sequential interval loading, by placing the straw at 1 cm above the liquid nitrogen (LN₂) surface for 60 s during freezing and 2 cm above the LN₂ for 2 min during thawing. This method was applied in cryopreservation for the normozoospermic specimens and compared with a conventional slow freezing method. The results were better than those in the control group in the total motility recovery rate (77.8 ± 11.2% vs 56.6 ± 11.9%, P < 0.01), progressive motility recovery rate (77.6 ± 13.2% vs 47.7 ± 14.6%, P < 0.01), 24 h survival index (60.9 ± 13.4% vs 42.1 ± 14.1%, P < 0.01) and the sperm DNA fragment index (4.2 ± 3.7% vs 5.8 ± 3.7%, P = 0.126). This method was applied to the oligozoospermic specimens. Motile spermatozoa could be found in 12 of 15 cases in the ultra-rapid freezing group, while only in 7 cases in control group. The results indicated that this freezing method was simple, convenient and bio-safe for cryopreservation of severe oligozoospermic specimens.

Failed sperm retrieval from severely oligospermic or non-obstructive azoospermic patients on oocyte retrieval day: Emergent oocyte cryopreservation is a feasible strategy

Purpose

Unexpected sperm retrieval failure on the day of oocyte retrieval is not common but frequently happened in patients with severe oligospermia or non-obstructive azoospermia(NOA). Oocyte cryopreservation is a common strategy after failed collection of sperm when concurrent ovarian stimulation is underwent. However, the use of oocyte vitrification in such male-infertility cases remains unclear.

Objective

To investigate the outcomes of emergent oocyte cryopreservation after failed sperm retrieval from severe oligospermic or non-obstructive azoospermic (NOA) patients on oocyte retrieval day.

Methods

Design: Retrospective cohort study

Setting: Academic fertility center at Lee Women's Hospital, Taiwan, between March 2015 and August 2017.

Patients: For 203 couples with NOA(n = 200) or severe oligospermia(n = 3), testicular spermatozoa (n = 67 cycles) or frozen donor sperm (n = 209 cycles) were injected into fresh or frozen-thawed oocytes via 276 intracytoplasmic sperm injection (ICSI) cycles.

Main Outcome Measures: Clinical pregnancy and live-birth rates (LBRs).

Results

In the 67 cycles involving the use of fresh testicular spermatozoa, no significant differences were observed between fresh and warmed oocytes with respect to the fertilization rates (69.2% vs. 74.1%; p = 0.27), number of Day-3 embryos (8.6±4.4 vs. 6.4±3.4; p = 0.08), number of good-quality Day-3 embryos (4.5±3.9vs. 4.7±3.0; p = 0.45), implantation rates (29.1% vs. 17.8%; p = 0.21), clinical pregnancy rates (36.4% vs. 26.8.0%; p = 0.81), live birth rates (36.4% vs. 14.3%; p = 0.46), or perinatal outcomes. In the 209 cycles involving the use of frozen donor sperm, no significant differences were seen between the two groups, except that the mean birth weights were significantly lower with fresh oocyte pregnancies than with warmed oocytes (2952±196 gm vs 2643±700 gm; p = 0.006).

Conclusions

Emergent oocyte cryopreservation is a feasible strategy to manage unexpected sperm retrieval failure from severe oligospermic or NOA patients on the oocyte retrieval day. There is no detrimental effect on the live birth rate when testicular spermatozoa or frozen donor sperm are injected into the thawed oocytes compared with fresh oocytes.

Cryopreservation media differentially affect sperm motility, morphology and DNA integrity

INTRODUCTION

Human sperm freezing is very widely used for male fertility preservation. This procedure consists in adding cryoprotectants to the spermatozoa followed by cooling and storing the spermatozoa at a subzero temperature. Many standardized cryopreservation media are available on the market. However, these media differ in their chemical composition and there are no sufficient data to optimize their classification. Therefore, the aim of this study was to compare five commercially available sperm cryopreservation media, which have not been compared together, in terms of motility, morphology and DNA integrity.

MATERIALS AND METHODS

One-hundred semen samples were obtained from 10 fertile participants and 90 infertile men. Each sample was evaluated before freezing for motility, morphology and DNA fragmentation index (DFI). Then, it was equally divided into five aliquots. Each aliquot was cryopreserved using one of the five media (A, B, C, D, and E). The same parameters were re-evaluated after the addition of the cryopreservation media in the fertile group, and after sperm thawing in fertile and infertile groups.

RESULTS

The results showed that the five selected cryopreservation media had negative effects on sperm motility and morphology per se. In the infertile group, the cryosurvival factor was significantly lower in cryomedium A when compared to the four other media (p < 0.001). In addition, a significantly higher percentage of sperm with coiled tail was detected in cryomedium E compared to cryomedium A (p < 0.05) and to cryomedium B (p < 0.001) after thawing, in the infertile group. Furthermore, the sperm DFI was significantly higher in cryomedia A (p < 0.001), B (p < 0.001), C (p < 0.01), D (p < 0.01) and E (p < 0.05) compared to that of the fresh semen derived from infertile participants.

CONCLUSION

This study indicates that the recovery rate of competent spermatozoa, after cryopreservation, is still critical in infertile men. Therefore, frozen semen sample should be used only when necessary.

Application of testicular spermatozoa cryopreservation in assisted reproduction

OBJECTIVE

To evaluate the efficiency of spermatozoa cryopreservation and to compare the clinical pregnancy outcomes in intracytoplasmic sperm injection (ICSI) using fresh versus cryopreserved spermatozoa collected by testicular sperm aspiration (TESA).

METHODS

A retrospective study was performed to compare the outcomes of men who accepted frozen-spermatozoa-based TESA-ICSI with those of men who underwent TESA-ICSI using fresh spermatozoa between January 1, 2015, and December 30, 2016. The groups were matched for age. The rates of fertilization, good-quality embryos, blastocyst formation, and clinical pregnancy outcomes were obtained from clinical records and were compared between the groups.

RESULTS

There were no significant differences between the frozen TESA group (n=79) and the fresh TESA group (n=194) in the rates of fertilization (71.4% vs 73.4%), good-quality embryos (55.3% vs 54.5%), blastocyst formation (60.9% vs 60.1%), clinical pregnancy (61.7% vs 55.1%), and live delivery (51.1% vs 45.7%) (P>0.05 for all comparisons).

CONCLUSION

Freezing low-count sperm collected by TESA with a cryoprotectant was an efficient method in the treatment of male factor infertility.

Intracytoplasmic sperm injection: state of the art in humans

Among infertile couples, 25% involve both male and female factors, while male factor alone accounts for another 25% due to oligo-, astheno-, teratozoospermia, a combination of the three, or even a complete absence of sperm cells in the ejaculate and can lead to a poor prognosis even with the help of assisted reproductive technology (ART). Intracytoplasmic sperm injection (ICSI) has been with us now for a quarter of a century and in spite of the controversy generated since its inception, it remains in the forefront of the techniques utilized in ART. The development of ICSI in 1992 has drastically decreased the impact of male factor, resulting in millions of pregnancies worldwide for couples who, without ICSI, would have had little chance of having their own biological child. This review focuses on the state of the art of ICSI regarding utility of bioassays that evaluate male factor infertility beyond the standard semen analysis and describes the current application and advances in regard to ICSI, particularly the genetic and epigenetic characteristics of spermatozoa and their impact on reproductive outcome.