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During the fertility test of a couple, a spermogram (seminogram, or spermiogram) is always performed on the man. By evaluating several sperm parameters, this biological examination can reveal several sperm abnormalities including azoospermia, a complete absence of spermatozoids.
What is azoospermia?
Azoospermia is a semen anomaly characterized by the complete absence of spermatozoids in sperm. It obviously leads to male infertility because without spermatozoids there can be no fertilization.
Azoospermia affects less than 1% of men in the general population, i.e. 5 to 15% of infertile men.
Causes of azoospermia
Depending on the cause, there are two types of azoospermia:
NOA, for non-obstructive azoospermia
- Spermatogenesis is disturbed or absent and the testicles do not produce sperm. The cause of this defect in spermatogenesis may be hormonal, with hypogonadism (absence or abnormality of secretion of sex hormones), which may be congenital (e.g. Kallmann syndrome) or acquired, in particular by tumors of the pituitary gland that alter the function of the hypophyseal axis, or after treatment (e.g. chemotherapy).
- Genetics: Klinefelter syndrome (KS) (presence of an additional X chromosome) affecting 1 in 1200 males, chromosome structure abnormality (microdeletion, i.e. loss of a fragment, particularly the Y chromosome), translocation (one chromosome segment separates and bonds to another). These chromosomal abnormalities are responsible for 5.8% of male infertility problems;
- Bilateral cryptorchidism: both testicles do not descend into the scrotum, which alters the process of spermatogenesis;
- Infections: prostatitis, orchitis.
Obstructive or excretory azoospermia (OA, obstructive azoospermia)
Although spermatozoids are produced by the testicles, they cannot be released due to a blockage in the ducts (epididymis, vas deferens, or ejaculation ducts). The reason for this may be due to the following causes :
- Congenital: the vas deferens have been altered since embryogenesis, resulting in the lack of vas deferens. In men with cystic fibrosis, a mutation in the CFTR gene can cause a lack of vas deferens;
- Infectious: the ducts were obstructed as a result of infection (epididymitis, prostatic vesiculitis, prostatic utricle).
The main symptom of azoospermia is infertility.
The diagnosis of azoospermia is made during an infertility consultation, which in men always includes a spermogram. This examination consists of analyzing the content of ejaculate (semen), evaluating various parameters, and comparing the results with the standards established by the WHO.
In the case of azoospermia, no spermatozoa are found after centrifugation of the entire ejaculate. However, to make the diagnosis, it is necessary to perform one or even two additional spermograms with an interval of 3 months, since spermatogenesis (sperm production cycle) takes about 72 days. If no sperm is produced in 2 or 3 consecutive cycles, the diagnosis is azoospermia.
Several complementary tests are carried out to refine the diagnosis and try to determine the cause of this azoospermia:
- A clinical examination with palpation of the testicles, measurement of testicular volume, palpation of the epididymis, the vas deferens.
- A biochemical examination of the semen to analyze the various secretions (zinc, citrate, fructose, carnitine, acid phosphates, etc.) contained in the seminal plasma and coming from the various glands of the genital tract (seminal vesicle, prostate, epididymis). In the case of obstructed ducts, these secretions can be disturbed and biochemical analysis can help to locate the degree of obstruction.
- A hormonal assessment by a blood test, including measurement of FSH (follicle-stimulating hormone). A high level of FSH indicates testicular damage, a low level of FSH indicates damage in the hypothalamic hypophyseal axis.
- Serology by taking blood samples to look for an infection, such as chlamydia, which may have caused damage to the excretory organs.
- Scrotal ultrasound to examine the testicles for abnormalities of the seminal or epididymis duct.
- Karyotype Genetic Test to look for a genetic abnormality.
- A testicular biopsy in which a tissue fragment is removed from the interior of the testis under anesthesia.
- An x-ray or MRI scan of the pituitary gland is sometimes offered when a tumor is suspected.
Treatment and prevention
In the case of secretory azoospermia of hormonal origin, hormonal treatment may be proposed to restore the hormonal secretions necessary for spermatogenesis.
In other cases, sperm can be obtained surgically, either from the testicle during testicular biopsy (TESE technique: Testicular Sperm Extraction) in the case of secretory azoospermia or from the epididymis (MESA technique, Microsurgical epididymal sperm aspiration) in the case of obstructive azoospermia.
If sperm are obtained, they can be used immediately after biopsy (synchronous collection) or after freezing (asynchronous collection) during IVF (in vitro fertilization) with ICSI (intracytoplasmic sperm injection). This technique consists of the direct injection of a single sperm directly into each mature egg cell. Since the spermatozoid is selected and fertilization is “forced”, ICSI generally achieves better results than conventional IVF.
If no sperm can be obtained, the couple can be offered IVF using sperm from a donor.