WHO laboratory manual for the examination and processing of human semen

Infertility and problems of impaired fecundity have been a concern through ages and is also a significant clinical problem today, which affects 8-12% of couples worldwide. Of all infertility cases, approximately 40-50% is due to "male factor" infertility and as many as 2% of all men will exhibit suboptimal sperm parameters. It may be one or a combination of low sperm concentration, poor sperm motility, or abnormal morphology. The rates of infertility in less industrialized nations are markedly higher and infectious diseases are responsible for a greater proportion of infertility. The present literature will help in knowing the trends of male factor infertility in developing nations like India and to find out in future, various factors that may be responsible for male infertility.

Trends of male factor infertility, an important cause of infertility: A review of literature.

Current treatments of subfertile couples are usually empiric, as the true cause of subfertility often remains unknown. Therefore, we outline the role of nutritional and biochemical factors in reproduction and subfertility. A literature search was performed using MEDLINE, Science Direct and bibliographies of published work with both positive and negative results. The studies showed that folate has a role in spermatogenesis. In female reproduction, folate is also important for oocyte quality and maturation, implantation, placentation, fetal growth and organ development. Zinc has also been implicated in testicular development, sperm maturation and testosterone synthesis. In females, zinc plays a role in sexual development, ovulation and the menstrual cycle. Both folate and zinc have antioxidant properties that counteract reactive oxygen species (ROS). Thiols, such as glutathione, balance the levels of ROS produced by spermatozoa and influence DNA compaction and the stability and motility of spermatozoa. Oocyte maturation, ovulation, luteolysis and follicle atresia are also affected by ROS. After fertilization, glutathione is important for sperm nucleus decondensation and pronucleus formation. Folate, zinc, ROS and thiols affect apoptosis, which is important for sperm release, regulation of follicle atresia, degeneration of the corpus luteum and endometrial shedding. Therefore, the concentrations of these nutrients may have substantial effects on reproduction. In conclusion, nutritional and biochemical factors affect biological processes in male and female reproduction. Further research should identify pathways that may lead to improvements in care and treatment of subfertility.

The importance of folate, zinc and antioxidants in the pathogenesis and prevention of subfertility

A retrospective analysis of results from 114 initiated in-vitro fertilization cycles utilizing pronuclear embryo transfer is presented. Patients were unselected for age or infertility criteria, constituted a continuous series and were grouped according to response to stimulation (Group 1, ideal; Group 2, suboptimal) or ovarian reserve (Group 3, poor). At 16-18 h post-insemination, embryos were scored for alignment of pronuclei and nucleoli and the appearance of the cytoplasm, generating an embryo score (ES). Transfers were performed 24-26 h post-insemination using two to six embryos with the highest ES. A corrected score was calculated (total score/number of embryos; CS). A total of 114 initiated cycles resulted in 97 oocyte retrievals with 38 clinical pregnancies (39%; 15% implantation). Pregnancy rates were significantly different between the three groups; 37 pregnancies in Group 1 (55% clinical pregnancy; 20% implantation), none in Group 2 and one in Group 3 (6%; 2% implantation: P 15 resulted in a 28% implantation; 65% delivery rate. CS <14 resulted in four pregnancies, one delivered. The data show that oocyte quality and pronuclear embryo morphology are related to implantation and that pronuclear embryos can be successfully selected for embryo transfer.

The successful use of pronuclear embryo transfers the day following oocyte retrieval.

Effects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial.

The evaluation of the morphology of human spermatozoa varies widely between and sometimes even within laboratories. The purpose of this study was to determine whether the method that has been developed in our laboratory and which resulted in the use of stricter criteria for the evaluation of sperm morphology is a practical, reliable and repeatable method and to establish the within and between observer variations. The criteria used for a 'normal' spermatozoon are based on the appearance of spermatozoa found in the mucus of the upper endocervical canal. The results of the morphological evaluations of 26 samples by four observers were statistically analysed by various methods. The method of Barnett showed a high degree of relative accuracy between observers with error variances of between 2.89 and 19.67 as well as high Spearman rank correlation coefficients of between 0.8675 and 0.6537 (P less than 0.0003). The Spearman correlation coefficient for 15 duplicate evaluations by one observer was 0.9650 (P less than 0.0001) while the coefficients of variation for repeated evaluations of single samples were also within acceptable limits. Based on these results, the method described in this article allows comparable and reliable results between and within observers to be obtained. From this and other studies it can be concluded that the method also has a good prognostic value for the prediction of expected IVF fertilization, the hamster test and hemizona assay.

Theunis J.vW. Kotze

Papers

The evaluation of morphological characteristics of human spermatozoa according to stricter criteria