If you are attending a fertility clinic with your partner, semen analysis would be the basic test recommended for you, as it forms the cornerstone of male infertility evaluation. A semen sample is collected by masturbation into a clean, dry and sterile container. It may also be collected during coitus using special spermicidal lubricant free condoms. The man is required to be abstinent for at least 2-3 days prior to collection of the sample. The sample should be processed within 1 hour of collection. 2-3 samples taken a minimum of 2-3 days apart are evaluated because there may be daily variations in sperm number and quality .
If your semen analysis reports have just come and you are trying to interpret it before your scheduled appointment with your doctor, you may want to know about semen parameters in a healthy male. This article is going to help you find out what values are normal when it comes to semen parameters in a healthy male.
The various parameters assessed as part of semen analysis are:
1. Semen Volume
Semen volume is one of the physical parameters of routine semen analysis. Normal volume of semen ejaculated during an orgasm is around 1.5 ml to 5 ml.
A decrease in the semen volume may occur in case of retrograde ejaculation, congenital abnormalities or absence of the ducts or seminal vesicle, ductal obstruction, neurological problems, hormonal imbalance etc. Very rarely it so happens that the semen volume is large and it is usually due to contamination by urine.
The semen volume may vary in the same man on different occasions. Such a difference in semen volume is usually noticed if the interval between ejaculations is short.
Can low sperm volume cause infertility?
Low semen volume does not lead to male infertility, provided the other parameters of semen analysis are normal. A man with a normal semen volume may have low sperm counts resulting in difficulty impregnating his partner.
2. Semen Quality
Semen is initially thick in consistency. Within 5-25 minutes of ejaculation it normally becomes thin and flowy in consistency. The liquefaction of semen takes place due to action of enzymes added by the prostate. The change in consistency of the semen is tested by attempting to pour the semen drop by drop.
If the semen is found to be of thin and flowy in consistency immediately following ejaculation, possibilities such as ejaculatory duct obstruction or absence of seminal vesicles are to be considered.
Sometimes the semen may be too thick in consistency or may fail to liquefy. Normally semen sample should not show excessive sperm agglutination.
3. Semen Density
Sperm density refers to the number of sperms present per unit of semen sample and is synonymous to sperm count. Normal sperm count is anything above 15 million/ml. Decreased sperm count is called oligozoospermia and total absence of sperm in semen is called azoospermia.
To confirm azoospermia or absence of sperms in semen ,the sample should be examined under microscope after centrifugation. Men with azoospermia should be evaluated for ejaculatory duct obstruction and hormonal irregularities. In case of azoospermia, a post ejaculatory urine sample should be examined for sperms because sometimes the sperms may be travelling backwards into the urinary bladder instead of out of the penis during ejaculation, which is called retrograde ejaculation.
4. Semen Motility
The sperm moves with the help of a flagellum popularly known as the tail of the sperm. The sperm normally moves at a speed of 1mm/min to 4mm/min. Normal motility of the sperm is essential for transportation of the sperm through the female genital tract and successful fertilization of the ovum. The grading of sperm motility is as follows :
Grade 0 refers to no movement
Grade 1 is sluggish movement
Grade 2 is slow but not straight movement
Grade 3 is movement in a straight line
Grade 4 is terrific speed
It is considered to be normal, if more than 60% of the sperms in a semen sample tested show normal motility.
Abnormal sperm motility occurs in men with testicular infections, partial duct obstruction or structurally abnormal sperms.
If low sperm motility is identified as the cause for male infertility, it is natural for a couple to wonder how to conceive with low sperm motility. If all the other parameters are found to be normal and decreased sperm motility is identified as the possible cause for infertility in a couple, intrauterine insemination (IUI) can be attempted. It is an assisted reproductive technique where the semen from the man is transferred directly into the uterine cavity of the female partner . By means of intrauterine insemination technique, the vaginal and cervical portions of the female genital tract are bypassed. As a result the sperm with decreased motility has to traverse a shorter path to reach the ovum for fertilization.
5. Semen Morphology
Sperm morphology refers to the anatomical aspects of sperm such as its size and shape. The different parts of the sperm such as head, acrosome, mid-piece, tail etc are examined in detail under phase contrast microscope after staining with special papanicolaou stain.
Normal sperms have smooth oval head and are 3-5 micrometer long and 2-3micrometre wide. Mature sperms may contain few droplets of cytoplasm in the mid-piece but excessive retained cytoplasmic droplets may be abnormal. Around 200 sperms are examined out of which more than 60% of the sperms in a semen sample should be of normal morphology and less than 2-3 % should be immature forms.
Does sperm shape affect fertility?
Yes, abnormally shaped sperms have less chance of successfully fertilizing an ovum as certain structural factors such as the acrosome are important for the process of fertilization.
6. Semen Biochemical Analysis
Biochemical analysis of semen involves testing for levels of zinc, citric acid, acid phosphatase, alpha glucosidase etc.
Each ejaculation should normally contain about 2.4micro moles of zinc in it. If the zinc levels are found to be low, the test may be repeated. A repetitively low level of zinc in the ejaculate may be suggestive of prostatic dysfunction or ductal obstruction.
Fructose levels in each ejaculation should be 13micro moles. Low levels of fructose in the ejaculate may be suggestive of dysfunction, obstruction or absence of seminal vesicles.
Glucosidase levels should normally reach levels of >20milli units per ejaculation.
7. Semen Cell Counts
The semen is examined for the various cell types present in it. Normally semen sample is devoid of any type of blood cells. A large number of white blood cells may be present in the semen if there is an infection or inflammatory process going on in the genital tract. On microscopy the sperms and white blood cells may both appear round. If more than 5-10 round cells are present on microscopic examination of semen sample, then immuno-histochemical staining technique is performed so as to differentiate between sperms and white blood cells
8. Test for Antisperm Antibody
Sperm contains various unique antigens which are not recognized as self by the body’s immune system. This is so because of an intact blood testis barrier. Under normal circumstances antisperm antibodies are not present. If the blood testis barrier is breached due to infection, testicular trauma, vasectomy, torsion of testis etc, antisperm antibodies may form.
Antisperm antibodies bind to the sperms and may cause clumping of the sperms. It may also lead to decreased sperm motility. The antisperm antibodies may make the sperms incapable of penetrating the cervical mucus and the ovum .
Detection of antisperm antibodies in the semen is done by means of radioimmunoassay or enzyme linked immunosorbent assay (ELISA ). The most specific test is immunobead. More than 15-20 % bound is considered positive for antisperm antibody.
If your semen tests positive for antisperm antibodies you may be keen on finding out do antisperm antibodies cause infertility.
Do antisperm antibodies cause infertility?
Yes, antisperm antibodies are capable of causing male infertility. As already detailed antisperm antibodies may lead to clumping of the sperms and decrease their motility. Clumped sperms with reduced motility decrease the chances of sperms reaching the ovum and fertilizing it.
Besides the usual parameters of semen analysis, male infertility evaluation may sometimes warrant the testing of functional capacity of the sperms. This is achieved through advanced sperm function tests. In case of male infertility which is not adequately explained by the usually tested parameters, sperm dysfunction also needs to be ruled out.