Critical assessment of sperm morphology before and after double wash swim-up preparation for in vitro fertilization

Male Infertility Diagnosis and Treatment in the Era of In Vitro Fertilization and Intracytoplasmic Sperm Injection

As assisted reproductive technologies use increases, the evaluation of male factor infertility has often become overlooked. However, male evaluation remains critically important, with benefits seen in overall health, as well as in natural and assisted pregnancy and birth rates. A comprehensive assessment of the male partner should be offered to all couples seeking infertility care.

Correlation of post swim-up acrosome index with in-vitro fertilization outcomes

PURPOSE

A prospective study was planned to determine the relationship between post swim-up acrosome index (AI) evaluation and fertilization outcomes in an in vitro fertilization (IVF) program.

MATERIALS AND METHODS

Infertile couples who have applied to IVF were admitted into this study when the male partner's sperm concentration was > 20 x 10(6)/mL and motility > 30%. Pre- and post swim-up semen quality parameters including concentration, motility, sperm morphology and AI were evaluated in a prospective, randomized and blinded fashion. The couples were divided prospectively into 2 groups. In group I (25 couples) 50 000 sperm per oocyte were used for insemination considering post swim-up acrosome index, and in group II (25 couples) 50 000 sperm per oocyte were used for insemination without considering post swim-up acrosome index.

RESULTS

Pre- and post swim-up AI were 30.8 +/- 3.4 and 17.8 +/- 4.5 in group I, and 31.4 +/- 3.6 and 16.3 +/- 4.7 in group II (p > 0.05) respectively. The significant improvement in morphology and motility after double wash swim-up procedure has been observed. However, double wash swim-up procedure could not eliminate head and especially acrosomal defects which would directly effect fertilization capacity in conventional IVF program. In group I, 85.3% of oocytes were fertilized, with a 48% pregnancy rate; in group II, 71.0% of oocytes were fertilized, with a pregnancy rate of 20%. Fertilization and pregnancy rates were significantly different (p < 0.05) between the two groups.

CONCLUSION

We have concluded that it could be useful to consider post swim-up AI of sperm inseminated in conventional IVF cycles, which correlates with high fertilization and pregnancy rates.

The relationship between critical evaluation of sperm morphology and the TYB-optimized zona free hamster oocyte sperm penetration assay

The objective of this study was to analyse the relationship between the percentage of spermatozoa in semen with normal morphology, assessed using the Tygerberg criteria, and sperm fertilizing ability assessed using the TYB-optimized zona free hamster oocyte sperm penetration assay (TYB-optimized SPA), to evaluate the predictive value of strict morphology on outcome of the SPA. In a retrospective study, 56 samples were analysed. In addition to routine semen parameters, the percentage of spermatozoa with normal morphology (A forms) and the average number of penetrations per oocyte (Sperm Capacitation Index) was evaluated in all cases. Using a multiple linear regression analysis with all semen parameters, sperm morphology was the best predictor (p = 0.001) of the SPA score. The agreement between the percentage of A forms and the Sperm Capacitation Index beyond chance (kappa coefficient) was 0.5842. Twenty-two specimens had abnormal SPA scores, with 21 exhibiting abnormal sperm morphology (Sensitivity = 96%). The remaining 34 samples had normal Sperm Capacitation Index values; of these, 23 had normal sperm morphology in semen (Specificity = 68%). The positive predictive value was 96%, and the negative predictive value was 66%. All semen samples from control donors had normal semen parameters and Sperm Capacitation Index values. In conclusion, the percentage of spermatozoa with normal morphology assessed using Tygerberg criteria (> 14% A forms) are predictive of the results in the TYB-optimized SPA. However, sperm morphology appears to be a better predictor when it is normal than when it is abnormal.

The combination of two semen preparation techniques (glass wool filtration and swim-up) and their effect on the morphology of recovered spermatozoa and outcome of IVF-ET

The aim of this prospective study was to relate sperm quality, especially sperm morphology, to the outcome of IVF results, when glass wool filtration (GWF) and swim-up were used in combination for the preparation of spermatozoa. A total of 60 ejaculates were analysed. GWF was compared with glass wool filtration/swim-up (GWF-SU) by using aliquots from the same semen samples to increase the precision of the comparison and to establish the cumulative effect of these two semen preparation methods on the morphology of the recovered spermatozoa. Sperm parameters were examined in native semen, in semen preparation samples after GWF and GWF-SU. The mean percentages for motility, morphology and velocity were improved significantly over those in fresh semen only when GWF-SU was used. GWF alone resulted only in a significantly higher recovery of motile spermatozoa. In semen preparation, 10% of spermatozoa with normal morphology appeared to be the cut-off point as there was a significantly higher recovery in fresh semen samples containing > 10% morphologically normal spermatozoa after GWF-SU. Outcome of IVF-ET following preparation with GWF-SU showed better results in comparison to the swim-up procedure alone, though this difference was not statistically significant. The cut-off point was also > 10% morphologically normal spermatozoa. Improvement in all aspects of IVF-ET occurred when native semen contained > 10% morphologically normal spermatozoa. It is concluded that GWF alone did not produce significantly better results but, in combination with swim-up, it resulted in significantly better sperm morphology and in an improved outcome of IVF-ET for fresh semen samples with > 10% morphologically normal spermatozoa.

Strict criteria for the evaluation of human sperm morphology and its impact on assisted reproduction

Sperm morphology abnormalities can be identified in a large proportion of patients with failed and delayed fertilization when assessing this parameter with strict criteria. Statistical analyses of a large IVF population confirm that, in patients with severe teratozoospermia, fertilization rates can be enhanced in many cases by increasing insemination concentration. However, implantation rates are impaired, thereby affecting the ability of these patients to establish a viable pregnancy. Data from couples undergoing controlled ovarian stimulation/intrauterine insemination seem to support the use of strict morphology as a predictor of outcome in this setting, too. Although a descriptive parameter, sperm morphology assessed by strict criteria can be used as a biomarker of sperm dysfunction(s). These dysfunctions are multiple and include abnormalities of motion parameters, poorer capacity to bind to homologous zona pellucidae and penetrate zona-free eggs, and low incidence of spontaneous and induced acrosome reaction. At a cellular level, poor morphology is associated with a higher content of creatine kinase and impaired capacity to undergo appropriate changes in intracellular calcium concentration. Whether nuclear/DNA abnormalities are present still remains to be fully determined. A definitively objective evaluation of morphology based on these criteria may allow all centres specializing in assisted reproduction to analyse semen in a homogeneous fashion.

Correlation between sperm morphology using strict criteria in original semen and swim-up inseminate and human in vitro fertilization

To study the value of sperm morphology using strict criteria in raw semen and in swim-up inseminate of human in vitro fertilization (IVF), 135 cycles of IVF with normal sperm concentration and motility were recruited. At least two mature oocytes were recovered in each cycle. The correlation between the percentages of normal forms and fertilization rates of mature oocytes was analyzed. The results demonstrate that the percentage of normal forms in both the raw semen and swim-up sample of patients with poor fertilization was significantly lower than in those with acceptable fertilization. The percentages of normal forms both in raw semen and in swim-up sample were significantly correlated with fertilization rates in vitro, however, the former seemed to have a better correlation (r = .51 and .19, respectively). Regarding the percentages of normal forms in raw semen, the fertilization rate in patients with normal forms < 4% was 6 +/- 11%, for 4-14% it was 58 +/- 36%, and for > 14% it was 88 +/- 20%. The fertilization rates were significantly different among these three groups of patients. The evaluation of sperm morphology using strict criteria in raw semen before IVF is predictive of fertilization outcome and may also help doctors to choose an optimal method of treatment for patients.

Predictive value of morphologically normal sperm concentration in the medium for in-vitro fertilization

Morphological evaluation of spermatozoa using strict criteria (MEUSC) and conventional sperm parameters were studied with respect to in-vitro fertilization and pregnancy outcome before and after a swim-up selection procedure. Recovered oocytes were inseminated with 50,000 progressively motile spermatozoa, and this study assess the influence of the total number of spermatozoa and of the percentage with strictly normal morphology in the insemination sample on the outcome of IVF. The results showed that the percentages of spermatozoa with normal morphology using strict criteria, both in native and in post-swim-up samples, were the best predictors of IVF outcome. Their respective cut-off points were 5% and 8%. The number of morphologically normal spermatozoa inseminated also showed a good correlation with fertilization. However, it was not possible to find a proper cut-off point for this parameter. The patients were categorized on the basis of their native and post-swim-up scores. Category 1, in which both parameters were below their respective cut-off points, showed a 7% fertilization rate and a 0% pregnancy rate. Category 3, in which both parameters were above their cut-off points, showed a 70% fertilization rate and a 23% pregnancy rate. This suggests that sperm morphology can be used as a criterion for patient selection for IVF as an aid to identification of possibly subfertile males.

Sperm selection capacity of the human zona pellucida

Previous hemizona assay (HZA) results have illustrated a positive and significant correlation between the percentage of morphologically normal spermatozoa in the semen and the number of spermatozoa tightly bound to the zona pellucida. The present study was designed to evaluate the morphologic features using strict criteria of spermatozoa tightly bound to the zona pellucida. Semen samples of 4 normozoospermic and 11 teratozoospermic men were used to compare the percentage of normal spermatozoa in the semen with that found 1) after swim-up separation and 2) bound to the zona under HZA conditions. The mean (+/- SEM) % normal forms for normozoospermic men in semen, after swim-up and zona-bound spermatozoa were 21.5 +/- 1.6, 27.5 +/- 2.9, and 44.8 +/- 3.4, respectively. A significantly higher % of normal forms were found among zona-bound sperm compared to swim-up forms (p = 0.02) and seminal sperm (p = 0.02). The mean % of normal sperm forms present in semen, after swim-up and zona pellucida-binding for teratozoospermic men, were 3.7 +/- 0.9, 5.8 +/- 1.6 and 15.6 +/- 3.1, respectively. Significant differences existed between the % of normal sperm forms found in the swim-up and zona-bound spermatozoa (P = less than 0.01 and P = less than 0.0003, respectively) compared to the original ejaculates. Results indicate that a selective process against abnormal spermatozoa occurs at the site of the zona pellucida.(ABSTRACT TRUNCATED AT 250 WORDS)