Clinical relevance of sperm morphology assessment using strict criteria and relationship with sperm-mucus interaction in vivo and in vitro

Semen evaluation: methodological advancements in sperm quality-specific fertility assessment - A review

Assessment of male fertility is based on the evaluation of sperm. Semen evaluation measures various sperm quality parameters as fertility indicators. However, semen evaluation has limitations, and it requires the advancement and application of strict quality control methods to interpret the results. This article reviews the recent advances in evaluating various sperm-specific quality characteristics and methodologies, with the help of different assays to assess sperm-fertility status. Sperm evaluation methods that include conventional microscopic methods, computer-assisted sperm analyzers (CASA), and flow cytometric analysis, provide precise information related to sperm morphology and function. Moreover, profiling fertility-related biomarkers in sperm or seminal plasma can be helpful in predicting fertility. Identification of different sperm proteins and diagnosis of DNA damage has positively contributed to the existing pool of knowledge about sperm physiology and molecular anomalies associated with different infertility issues in males. Advances in methods and sperm-specific evaluation has subsequently resulted in a better understanding of sperm biology that has improved the diagnosis and clinical management of male factor infertility. Accurate sperm evaluation is of paramount importance in the application of artificial insemination and assisted reproductive technology. However, no single test can precisely determine fertility; the selection of an appropriate test or a set of tests and parameters is required to accurately determine the fertility of specific animal species. Therefore, a need to further calibrate the CASA and advance the gene expression tests is recommended for faster and field-level applications.

How accurate is sperm morphology as an indicator of sperm function?

Sperm morphology has been consistently correlated with fertilisation success or failure. The clinical relevance of the percentage normal spermatozoa has been a widely discussed topic amongst infertility specialists and scientists. This study aimed to evaluate the role of sperm morphology as an indicator of additional sperm functions among 114 andrology referrals. The sperm functions that were investigated included chromatin packaging quality (CMA3 test (n = 109), zona-induced acrosome reaction (ZIAR test; n = 36), hemizona assay (HZI; n = 36) and progressive motility (n = 47). Chromatin packaging quality had a negative and significant (P = 0.0001, r = -0.74) correlation with the percentage normal spermatozoa, while progressive motility had a significant and positive correlation (P = 0.0001, 0.59). Accurate sperm morphology scoring as described by the WHO 2010 manual can therefore be used as an indicator of specific sperm functions.

A common mutation in the defensin DEFB126 causes impaired sperm function and subfertility

A glycosylated polypeptide, β-defensin 126 (DEFB126), derived from the epididymis and adsorbed onto the sperm surface, has been implicated in immunoprotection and efficient movement of sperm in mucosal fluids of the female reproductive tract. Here, we report a sequence variant in DEFB126 that has a two-nucleotide deletion in the open reading frame, which generates an abnormal mRNA. The allele frequency of this variant sequence was high in both a European (0.47) and a Chinese (0.45) population cohort. Binding of the Agaricus bisporus lectin to the sperm surface glycocalyx was significantly lower in men with the homozygous variant (del/del) genotype than in those with either a del/wt or a wt/wt genotype, suggesting an altered sperm glycocalyx with fewer O-linked oligosaccharides in del/del men. Moreover, sperm from del/del carriers exhibited an 84% reduction in the rate of penetration of a hyaluronic acid gel, a surrogate for cervical mucus, compared to the other genotypes. This reduction in sperm performance in hyaluronic acid gels was not a result of decreased progressive motility (average curvilinear velocity) or morphological deficits. Nevertheless, DEFB126 genotype and lectin binding were correlated with sperm performance in the penetration assays. In a prospective cohort study of newly married couples who were trying to conceive by natural means, couples were less likely to become pregnant and took longer to achieve a live birth if the male partner was homozygous for the variant sequence. This common sequence variation in DEFB126, and its apparent effect of impaired reproductive function, will allow a better understanding, clinical evaluation, and possibly treatment of human infertility.

Semen analysis and sperm function testing

Despite controversy regarding the clinical value of semen analysis, male fertility investigation still relies on a standardized analysis of the semen parameters. This is especially true for infertility clinics in both developing and developed countries. Other optional tests or sophisticated technologies have not been widely applied. The current review addresses important changes in the analysis of semen as described in the new World Health Organization (WHO) manual for semen analysis. The most important change in the manual is the use of evidence-based publications as references to determine cutoff values for normality. Apart from the above mentioned changes, the initial evaluation and handling methods remain, in most instances, the same as in previous editions. Furthermore, the review evaluates the importance of quality control in andrology with emphasis on the evaluation of sperm morphology. WHO sperm morphology training programmes for Sub-Saharan countries were initiated at Tygerberg Hospital in 1995. The external quality control programme has ensured that the majority of participants have maintained their morphological reading skills acquired during initial training. This review reports on current sperm functional tests, such as the induced acrosome reaction, and sperm-zona pellucida binding assays, as well as the impact of sperm quality in terms of DNA integrity, and the relationship of sperm function tests to sperm morphology.

The effect of pulsed 900-MHz GSM mobile phone radiation on the acrosome reaction, head morphometry and zona binding of human spermatozoa

Several recent studies have indicated that radiofrequency electromagnetic fields (RF-EMF) have an adverse effect on human sperm quality, which could translate into an effect on fertilization potential. This study evaluated the effect of RF-EMF on sperm-specific characteristics to assess the fertilizing competence of sperm. Highly motile human spermatozoa were exposed for 1 h to 900-MHz mobile phone radiation at a specific absorption rate of 2.0 W/kg and examined at various times after exposure. The acrosome reaction was evaluated using flow cytometry. The radiation did not affect sperm propensity for the acrosome reaction. Morphometric parameters were assessed using computer-assisted sperm analysis. Significant reduction in sperm head area (9.2 ± 0.7 μm² vs. 18.8 ± 1.4 μm²) and acrosome percentage of the head area (21.5 ± 4% vs. 35.5 ± 11.4%) was reported among exposed sperm compared with unexposed controls. Sperm-zona binding was assessed directly after exposure using the hemizona assay. The mean number of zona-bound sperm of the test hemizona and controls was 22.8 ± 12.4 and 31.8 ± 12.8 (p < 0.05), respectively. This study concludes that although RF-EMF exposure did not adversely affect the acrosome reaction, it had a significant effect on sperm morphometry. In addition, a significant decrease in sperm binding to the hemizona was observed. These results could indicate a significant effect of RF-EMF on sperm fertilization potential.

Frozen-thawed rhesus sperm retain normal morphology and highly progressive motility but exhibit sharply reduced efficiency in penetrating cervical mucus and hyaluronic acid gel

The preservation of the genetic diversity of captive populations of rhesus monkeys is critical to the future of biomedical research. Cryopreservation of rhesus macaque sperm is relatively simple to perform, yields high post-thaw motility, and theoretically, provides via artificial insemination (AI) a way to easily transfer genetics among colonies of animals. In the interest of optimizing semen cryopreservation methods for use with vaginal AI, we evaluated the ability of frozen-thawed rhesus sperm to penetrate periovulatory cervical mucus (CM). Motile sperm concentration of pre-freeze ("fresh") and post-thawed ("thawed") samples from five different males were normalized for both computer assisted sperm motion analysis and CM penetration experiments. Sperm samples were deposited into slide chambers containing CM or gel composed of hyaluronic acid (HA) as a surrogate for CM and numbers of sperm were recorded as they entered a video field a preset distance from the sperm suspension-CM (or HA) interface. Fresh and thawed sperm were dried on glass slides, "Pap"-stained, and assessed for changes in head dimensions and head and flagellar shape. While retaining better than 80% of fresh sperm progressive motility, thawed sperm from the same ejaculate retained on average only 18.6% of the CM penetration ability. Experiments using HA gel yielded similar results only with reduced experimental error and thus improved detection of treatment differences. Neither the percentage of abnormal forms nor head dimensions differed between fresh and thawed sperm. While findings suggests that sperm-CM interaction is a prominent factor in previous failures of vaginal AI with cryopreserved macaque sperm, neither sperm motility nor morphology appears to account for changes in the ability of cryopreserved sperm to penetrate CM. Our data points to a previously unidentified manifestation of cryodamage which may have implications for assessment of sperm function beyond the cervix and across mammalian species.

Macaque sperm coating protein DEFB126 facilitates sperm penetration of cervical mucus

BACKGROUND

Sperm coating protein beta-defensin 126 (DEFB126) is adsorbed onto the entire surface of macaque sperm in the caudal epididymis and is retained on viable sperm collected from the cervix and the uterine lumen of mated female macaques. We investigated the role of sperm coating protein DEFB126 in cervical mucus penetration (CMP).

METHODS

Cervical mucus (CM) was collected from peri-ovulatory female macaques and loaded into CMP chambers. Sperm were introduced to CMP chambers following treatment with either polyclonal antibodies raised to DEFB126 or seminal plasma proteins (SPPs), 1 mM caffeine+1 mM dibutyryl cyclic adenosine monophosphate (dbcAMP) (induces release of DEFB126 from sperm surface), neuraminidase (NMase) or poly-L-lysine (PLP). Following removal of DEFB126 or SPPs from the sperm surface, sperm were treated with concentrated DEFB126 or concentrated SPPs prior to being introduced to CMP chambers. The numbers of sperm that penetrated and traversed CM were scored over 6 min.

RESULTS

Treatment of sperm with anti-DEFB126 antibodies, 1 mM caffeine+1 mM dbcAMP, NMase, and PLP resulted in similar and significant levels of inhibition of sperm CMP, whereas addition of anti-SPPs antibodies had no effect. In experiments where DEFB126 and SPPs were removed, CMP capability of sperm was restored by addition of DEFB126 back to the sperm surface, whereas treatment of sperm with concentrated SPPs slightly inhibited sperm penetration.

CONCLUSIONS

DEFB126 and its high negative charge appears to be critical for the movement of sperm through CM in the macaque, while SPPs adhered to the sperm surface offer no advantage in CMP.

Is fine morphology of the human sperm nuclei affected by in vitro incubation at 37°C?

OBJECTIVE

Incubation of ejaculated spermatozoa at 37 degrees C is recommended for IVF-intracytoplasmic sperm injection. Preselection of sperm cells with morphologically normal nuclei before microinjection, adapted in our laboratory, is usually a time-consuming procedure. Therefore, we aimed to verify whether incubation at 37 degrees C could affect the morphologic integrity of sperm nuclei.

DESIGN

Time-kinetics studies testing fine morphology of the sperm nuclei upon prolonged in vitro incubation.

SETTING

Male Fertility Laboratory at Bar-Ilan University, Ramat Gan, Israel.

PATIENT(S)

Forty-two males selected at random, who were referred for sperm preselection before ICSI.

MAIN OUTCOME MEASURE(S)

Morphologic integrity of the sperm nuclei, obtained by motile sperm organelle morphology examination.

RESULT(S)

After 2 hours of incubation at 37 degrees C a significant decrease occurred in the morphologic integrity of the sperm nuclei, compared with the initial state (4.7% +/- 2.8% vs. 6.8% +/- 3.5%, t = 3.2, P<or=.01). Correspondingly, a significant increase occurred in the frequency of vacuolated nuclei (80.8% +/- 7.2% vs. 75.0% +/- 7.6%, t = -2.8, P<or=.01). No significant morphologic changes in sperm nuclei were observed upon prolonged incubation at 21 degrees C. After 2 hours of incubation, the incidence of spermatozoa with vacuolated nuclei was significantly higher at 37 degrees C compared with 21 degrees C (56.5% +/- 10.8% vs. 45.5% +/- 10%, t = 6.6, P<or=.01).

CONCLUSION(S)

Prolonged (>or=2 hours) sperm manipulations for assisted reproduction therapy should be performed at 21 degrees C rather than 37 degrees C.

Lessons learned from a sperm morphology quality control programme

Although sperm morphology is the sperm parameter that is consistently correlated with in vitro and in vivo fertilisation, its value is often challenged due to discrepancies in reports. As sperm morphology is subjectively evaluated, the outcome of the report is entirely based on the experience and technical skill of the laboratory technician responsible for semen analyses. The study aimed to record the value of quarterly monitoring and refresher courses on morphology reading skills of technicians over a period of 40 months. Nineteen individuals from 12 different andrology laboratories were enrolled to a sperm morphology quality control programme after initial training sessions. Five of the 19 participants attended annual refresher courses. Two limits of error, namely +/- 0.5 SD and +/- 0.2 SD scores, were used to record technician deviation from the reference laboratory. Fifteen of the 19 individuals (78%) consistently reported sperm morphology readings that were within the +/- 0.5 SD limits of error. Furthermore, five of the participants, who attended annual refresher training courses, consistently reported results that were within the +/- 0.2 SD limits of error. For the first time, it has been illustrated that excellent sperm morphology reading skills can be achieved and maintained by initial training sessions, followed up with a continuous external quality control programme and annual refresher courses.

The establishment of sperm morphology satellite training laboratories in Africa

Summary Discrepancies in the results of semen analysis can be caused by a variety of factors, for example, a microscope for semen analysis can be situated in the practice of an urologist, cytologist or microbiologist, or even in a health care office in the countryside in a developing country. The study aimed to evaluate the (i) sperm morphology assessment skills of the participants who attended WHO seminology workshops and (ii) to appraise the possibility of using trained technologists to set up satellite training facilities in their own area. The Centre for Research in Reproductive Health, Ogun State University Teaching Hospital (Nigeria) initiated training sessions in their area. Subsequently, 16 technologists were trained in three sessions. Papanicolaou-stained slides, supplied by Tygerberg were used as test material. Pre- and post-training results were used to calculate the mean percentage of normal cells as well as the percentage deviation from the reference laboratory. The mean percentage normal spermatozoa recorded by the Nigerian trainees during pre-training evaluations differed by 38% from the reference value, compared with a post-training difference of 16% (P < 0.001). Tertiary academic hospitals can play an important educational role in the region. The present results underline the power of long distance educational programmes. Similar laboratories are currently being set up in Kenya and Zambia.

Human cervical mucus can act in vitro as a selective barrier against spermatozoa carrying fragmented DNA and chromatin structural abnormalities

PURPOSE

We have carried out experiments to determine if human cervical mucus can act as an in vitro selective barrier against spermatozoa morphologically normal that carry genetic structural abnormalities.

METHODS

Sperm chromatin abnormalities have been evaluated by Chromomycin A3 and "endogenous" nick translation.

RESULTS

The data obtained have shown that spermatozoa possessing higher levels of DNA protamination are more proficient in crossing the cervical mucus barrier. Moreover, the levels of positivity to endogenous nick translation treatment was practically zero in such spermatozoa.

CONCLUSIONS

We suggest that sperm penetration of cervical mucus could be used to select sperm preparations free of fragmented DNA or chromatin structural abnormalities for assisted reproduction.

Differential expression of Toll-like receptors 2 and 4 in tissues of the human female reproductive tract

Toll-like receptor (TLR) signal transduction is a central component of the innate immune response to pathogenic challenge. Although recent studies have begun to elucidate differences in acquired immunity in tissues of the human female reproductive tract, there is a relative paucity of work regarding innate defense mechanisms. We investigated TLR mRNA and protein expression in tissues of the human female reproductive tract. Constitutive mRNA expression of TLRs 1 to 6 was observed in fallopian tubes, uterine endometrium, cervix, and ectocervix. Furthermore, transcripts of the signaling adapter MyD88 and the accessory molecule CD14 were also detected in all tissues assayed. Quantitative analysis of TLR2 mRNA levels revealed highest expression of this molecule in fallopian tube and cervical tissues, followed by endometrium and ectocervix. In contrast to TLR2, TLR4 expression declined progressively along the tract, with highest expression in the upper tissues (fallopian tubes and endometrium), followed by cervix and ectocervix. In addition to mRNA, protein expression of TLR2 and TLR4 was also documented in these tissues. These data suggest that TLRs are differentially expressed in distinct compartments of the female reproductive tract and may provide insight regarding the regulation of inflammation and immunity within the tract.

African experience with sperm morphology training courses

This paper reports on the results of a 6-year ongoing training and quality control programme for sperm morphology. The programme consists of a 5-day semenology workshop, during which participants receive intensive training on issues such as sperm concentration, motility, vitality and morphology. Following the workshop, all the participants are enrolled in a continuous quality control (CQC) programme for sperm morphology. These workshops and quality control programmes are presented by the Department of Obstetrics and Gynaecology at Tygerberg Hospital (South Africa) in conjunction with the World Health Organization's (WHO) Special Programme for Research Development and Research Training. Seventy individuals from 11 countries in sub-Saharan Africa have been trained since 1997; 58 of these are still participating in the quality control programme. Using the results from the quality control programme, participants were classified according to their sperm morphology reading skills recorded over an extended period. It is concluded that an external quality control programme can be highly successful, on condition that it is presented continuously with a 3-4 month interval between tests.

Interactive effect of semen and cervical mucus quality on postcoital test outcome: analysis from an andrological point of view

This study analysed the relationship between semen quality and the postcoital test (PCT) outcome in 616 couples, especially focusing on the interactive effect of semen and cervical mucus quality. When PCTs performed in the presence of unfavourable mucus were excluded, a significant correlation was found between semen parameters and PCT outcome. In oligo/asthenozoospermia, 46.7% of PCT outcomes were negative, while the remaining were positive. Notably, in the presence of an optimal mucus score, 39% of PCT outcomes were good (> or = 7 forward motile spermatozoa/high power field). In normozoospermia, 16% of PCT were negative. A suboptimal cervical mucus quality significantly affected the PCT outcome in the presence of oligo/asthenozoospermia, but not in normozoospermia. In couples with repeated PCT, a better mucus score was associated with a significant improvement of the PCT outcome. When the outcome of two PCTs performed in the same couples with an unmodified mucus score was compared, a good consistency of the results was observed. In conclusion, the PCT can provide information in additional to that obtained from conventional semen analysis, as the interactive effect of semen/cervical mucus cannot be accurately inferred from the separate evaluation of the two members of a couple.

Sperm chromatin packaging as an indicator of in-vitro fertilization rates

The development of a sequential diagnostic schedule for patients consulting for infertility disturbances would be an ideal method of approach for clinicians in the absence of an aetiological or pathophysiological diagnosis. Since sperm morphology recorded by strict criteria has often been correlated with fertilization failure, the present study aimed to evaluate the relationship between normal morphology as well as in-vitro fertilization (IVF) rates, with chromatin staining among fertile and subfertile men. Two semen smears were prepared from each specimen obtained from 72 men to record normal morphology and chromatin packaging as recorded by chromomycin A(3) (CMA(3)) staining. Following the semen analyses, the 72 men were divided into the two morphological groups, namely <4% and >4% normal forms. Significantly different percentages of CMA(3) staining (mean +/- SE) were recorded between the two morphological groups, namely 65.9% +/- 3.5 and 44.5% +/- 1.7 (P +/- 0.001). A highly negative significant correlation existed between percentage of normal morphology as recorded by strict criteria and CMA(3) staining. A highly significant and positive correlation was recorded for normal morphology and IVF rates (r +/- 0.45, P +/- 0.0001). A significant negative correlation (r +/- -0.51, P +/- 0.0001) existed between CMA(3) values and IVF rates. The discriminating power of nuclear maturity, as recorded by CMA(3) staining, to identify abnormal morphology values and poor IVF rates was calculated with receiver operator characteristic (ROC) analyses. The areas under the ROC curves were 0.86 for sperm morphology and 0. 74 for IVF rates. The calculated threshold values for CMA(3) staining to distinguish between morphology groups were 48 and 50% for IVF. Chromatin packaging assessment is a valuable addition to the sequential diagnostic programme in an assisted reproductive arena.

Normal sperm morphology and chromatin packaging: comparison between aniline blue and chromomycin A3 staining

The successful implementation of ICSI has provided a unique means of allowing couples suffering from severe male infertility to achieve their reproductive goals. However, despite the great therapeutic advantages of the technique, ICSI often provides solutions to clinicians in the absence of an aetiological or pathophysiological diagnosis. The development of a sequential diagnostic schedule for patients consulting for fertility disturbances would be an ideal method of approach. Since sperm morphology recorded by strict criteria has often been correlated with fertilization failure, the present study aimed to evaluate the relationship between normal morphology and chromatin staining among fertile and subfertile men. Both chromomycin A3 (CMA3) and acidic aniline blue (AAB) were employed to record chromatin packaging quality among 58 men visiting the andrology laboratory. Intra- and interassay variations were initially recorded for fertile sperm donors. The coefficients of variation (CV) for all intra- and inter-assay assessments were < 12%. Chromatin packaging was significantly and negatively correlated with normal sperm morphology, namely r = 0.40 (P = 0.001) and r = 0.33 (P = 0.001) for CMA3 and AAB, respectively. Receiver operator characteristics illustrated sensitivity and specificity values of 75% and 82% for CMA3 and 60% and 91% for AAB, respectively. Significantly different CMA3 and AAB staining was recorded among men with severe teratozoospermia (< 4% normal forms) when compared with normozoospermic men (> 14% normal forms), namely 49% vs. 29% for CMA3 and 51% vs. 26% for AAB staining, respectively. Chromatin packaging assessments should be a valuable addition to the sequential diagnostic programme in an assisted reproduction arena.

Comparison of human cervical mucus and artificial sperm penetration media

The cervical mucus penetration tests aid research and determine the clinical importance of positive sperm antibody tests. Limited availability and variability of human cervical mucus have instigated the search for mucus substitutes for these tests. This study compares sperm migration in cervical mucus with that in artificial media including hyaluronate solution, egg white and albumin Tyrode solution. Results were quantified by measuring the migration distance (the maximum distance of capillary migration from a semen reservoir by spermatozoa after 1 h) and the sperm concentration at half the migration distance. The mean of both measures for cervical mucus and hyaluronate solution were equivalent [4.4 +/- 1.1 (SD) versus 4.3 +/- 1.0 cm and 118 +/- 51 versus 111 +/- 44x10(3)/ml], and higher than in egg white and albumin Tyrode solution. Antisperm antibodies impaired sperm penetration in cervical mucus and hyaluronate solution in a similar manner (r = 0.92). These results suggest that hyaluronate solution sufficiently resembles human cervical mucus in terms of penetrability that it may be used as a substitute for mucus in capillary tube tests of sperm function. The higher penetrability of cervical mucus and hyaluronate solution is probably related to a channelling effect due to their polymeric structure.

Antisperm antibodies and microorganisms in genital secretions--a clinically significant relationship?

In asymptomatic infertility patients, no significant relationship was found between the presence of antisperm antibodies (ASA) in serum and in semen samples (IgG and/or IgA ASA), differentiated with the mixed antiglobulin reaction (MAR), and the microbial colonization of ejaculates covering a broad spectrum of microorganisms. Likewise, there was no significant association of ASA with microbial findings in patients' female partners, who also presented without symptoms of genital tract infection and were screened at the same time. Furthermore, ASA in semen (IgG and IgA) were not significantly related to several potential markers of subclinical male sexual gland infection or inflammation (leukocytes, PMN elastase, albumin, C3c) evaluated in aliquots of the same ejaculates used for immunological testing.

Chromatin cytophotometric analysis of abnormal bovine spermatozoa

Sperm head morphology is basically conditioned by the nuclear structure. The aim of the present work was to study the relation between nuclear morphological features, DNA content and chromatin distribution in morphologically normal vs. abnormal bovine spermatozoa. To this end, individual Feulgen-reacted spermatozoa were cytophotometrically studied. Chromatin compactation was evaluated by means of nuclear area, as well as mean and maximal absorbance of each nucleus. Morphological abnormality analysed included large, small, pear, narrow and round shapes, together with presumably 'diploid' sperms. Both large and small spermatozoa have a DNA content that does not differ significantly from normal values, but their area and mean and maximal absorbance are significantly different. Size variation seems basically due to altered chromatin compactation. The pear shapes have a narrower neck and a significant increase in maximal absorbance alone, which is invariably recorded in the neck zone whose increase would indicate a change in distribution and/or compactation. The narrow and round shapes fail to present significant variations in studied parameters. The possible 'diploids' differ significantly from normal cells in all studied variables, with a little area increase.

Use of the guanine-cytosine (GC) specific fluorochrome, chromomycin A3, as an indicator of poor sperm morphology

PURPOSE

We have previously postulated that the chromomycin A3 (CMA3) fluorochrome allows an indirect visualization of sperm chromatin packaging quality and partially denatured sperm DNA. In this study we investigate the relationship between CMA3 positivity and sperm morphology. We also present data on the association between sperm morphology and the presence of endogenous nicks in sperm DNA.

METHODS

Semen samples were examined from 81 males of the couples who were consulting for infertility treatment. CMA3 fluorescence was assessed for all samples, while in 24 sperm samples we also examined for the presence of endogenous nicks in the sperm DNA.

RESULTS

When sperm morphology was less than 20% normal in a patient, the level of CMA3 fluorescence and presence of endogenous nicks were significantly higher than in patients with a higher incidence of morphologically normal sperm.

CONCLUSIONS

CMA3 could be used as an adjunct to the assessment of morphology as an evaluation method for poor sperm. Its value in predicting fertilizing ability when using either SUZI or ICSI awaits to be answered.