Semen

Abstract: OBJECTIVE--To investigate whether semen quality has changed during the past 50 years. DESIGN--Review of publications on semen quality in men without a history of infertility selected by means of Cumulated Index Medicus and Current List (1930-1965) and MEDLINE Silver Platter database (1966-August 1991). SUBJECTS--14,947 men included in a total of 61 papers published between 1938 and 1991. MAIN OUTCOME MEASURES--Mean sperm density and mean seminal volume. RESULTS--Linear regression of data weighted by number of men in each study showed a significant decrease in mean sperm count from 113 x 10(6)/ml in 1940 to 66 x 10(6)/ml in 1990 (p < 0.0001) and in seminal volume from 3.40 ml to 2.75 ml (p = 0.027), indicating an even more pronounced decrease in sperm production than expressed by the decline in sperm density. CONCLUSIONS--There has been a genuine decline in semen quality over the past 50 years. As male fertility is to some extent correlated with sperm count the results may reflect an overall reduction in male fertility. The biological significance of these changes is emphasised by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and possibly also cryptorchidism and hypospadias, suggesting a growing impact of factors with serious effects on male gonadal function.

Abstract: This laboratory manual consists of 2 sections which describe methods of examination of human semen and semen-cervical mucus interaction in order to standardize procedures and facilitate evaluation and comparison of research reports The section on semen collection and examination discusses and makes recommendations for sample collection and delivery; initial examination; motility assessment estimation of sperm density; examination of particulate debris; agglutination; sperm viability; counting the spermatozoa; and analysis of morphological characteristics of germinal cells including preparation of seminal fluid smears staining method and classification and quantification of germinal cells and leucocytes Photomicrographs are provided to demonstrate morphological characteristics of normal and abnormal mature sperm immature germinal cells and leucocytes and epithelial cells Appendices provide information on frequency of various sperm forms in a normal ejaculate Papanicolaou staining procedure for sperm and the Bryan/Leishman stain for seminal fluid morphology smears A sample record for sperm analysis is also included The section on sperm-cervical mucus interaction describes the composition and characteristics of the mucus the collection procedure storage and preservation and evaluation including pH Methods of evaluating sperm-cervical mucus interaction are then described The timing and techniques of the post-coital test vaginal pool sample exocervical and low cervical samples and endocervical samples and their interpretation are discussed Instructions are provided for in vitro studies including the capillary tube test and the slide technique

Abstract: BACKGROUND Semen quality is taken as a surrogate measure of male fecundity in clinical andrology, male fertility, reproductive toxicology, epidemiology and pregnancy risk assessments. Reference intervals for values of semen parameters from a fertile population could provide data from which prognosis of fertility or diagnosis of infertility can be extrapolated. METHODS Semen samples from over 4500 men in 14 countries on four continents were obtained from retrospective and prospective analyses on fertile men, men of unknown fertility status and men selected as normozoospermic. Men whose partners had a time-to-pregnancy (TTP) of < or =12 months were chosen as individuals to provide reference distributions for semen parameters. Distributions were also generated for a population assumed to represent the general population. RESULTS The following one-sided lower reference limits, the fifth centiles (with 95th percent confidence intervals), were generated from men whose partners had TTP < or = 12 months: semen volume, 1.5 ml (1.4-1.7); total sperm number, 39 million per ejaculate (33-46); sperm concentration, 15 million per ml (12-16); vitality, 58% live (55-63); progressive motility, 32% (31-34); total (progressive + non-progressive) motility, 40% (38-42); morphologically normal forms, 4.0% (3.0-4.0). Semen quality of the reference population was superior to that of the men from the general population and normozoospermic men. CONCLUSIONS The data represent sound reference distributions of semen characteristics of fertile men in a number of countries. They provide an appropriate tool in conjunction with clinical data to evaluate a patient's semen quality and prospects for fertility.