Teratospermia (or teratozoospermia) is a spermatic abnormality characterized by spermatozoa with morphological defects. Because of these malformations, the fertilizing power of sperm is impaired, and the couple may have difficulty conceiving.
What is teratospermia?
Teratospermia is a spermatic abnormality characterized by spermatozoa with morphological defects. These abnormalities can affect different parts of the spermatozoon:
- the head, which contains the bearing nucleus of the 23 paternal chromosomes;
- the acrosome, a small membrane at the front of the head that, at the time of fertilization, will release enzymes that will allow the spermatozoon to cross the zona pellucida of the oocyte;
- the flagellum, this “tail” that allows it to be mobile and therefore to go back from the vagina to the uterus and then the tubes, for a possible encounter with the oocyte;
- The intermediate part located between the flagellum and the head.
Often, the anomalies are polymorphous: they can be multiple, of size or shape, to touch both the head and the flagellum, to vary from one spermatozoon to another. It may be a globozoospermia (absence of acrosome), double flagellum or double head, wound flagellum, etc.
All these anomalies have an impact on the fertilizing power of the spermatozoon, and thus on the fertility of the man. The impact will be more or less important depending on the percentage of normal sperm remaining. Teratospermia can reduce the chances of conception, or even lead to male infertility if it is severe.
Teratospermia is often associated with other spermatic abnormalities: oligospermia (insufficient number of spermatozoa), asthenospermia (lack of motility of the spermatozoa, so-called oligo-astheno-terazoospermia (OATS)).
The causes of Teratospermia
Like all spermatic abnormalities, the causes can be hormonal, infectious, toxic, medicated. The morphology of the spermatozoa is indeed the first parameter to be altered by external factor (exposure to toxins, infection,). More and more specialists also consider that atmospheric and food pollution (via pesticides in particular) has a direct impact on the morphology of spermatozoa.
But sometimes, no cause is found.
Symptoms of Teratospermia
The main symptom of teratospermia is the difficulty of conceiving. The fact that the spermatozoa form is abnormal does not affect the occurrence of malformations for the unborn child, but only the chances of pregnancy.
The diagnosis of Teratospermia
Teratospermia is diagnosed by spermogram, one of the first systematic examinations in humans during an infertility assessment. It allows a qualitative and quantitative study of sperm thanks to the analysis of different biological parameters:
- the volume of the ejaculate;
- the concentration of spermatozoa;
- the mobility of spermatozoa;
- the morphology of spermatozoa;
- The vitality of the spermatozoa.
The part concerning sperm morphology is the longest and most difficult stage of the spermogram. During an examination called spermocytogram, 200 spermatozoa are fixed and stained on smear slides. Then the biologist will study the different parts of the sperm under the microscope in order to evaluate the percentage of morphologically normal spermatozoa.
The type of morphological abnormalities is also taken into account to estimate the impact of teratospermia on fertility. Several classifications exist:
- the classification of David modified by Auger and Eustache, still used by some French laboratories;
- The Kruger classification, the WHO International Classification, is the most widely used in the world. Performed with the aid of an automaton, this more “severe” classification classifies at sperm any spermatozoon that deviates, even very little, from the form considered normal.
If the proportion of spermatozoa properly formed is less than 4% according to the WHO classification, or 15% according to the modified David classification, teratospermia is suspected. But as for any spermatic anomaly, a second or third spermogram will be performed at 3-month intervals (the duration of a spermatogenic cycle being 74 days) in order to make a firm diagnosis, especially since various factors may influence on sperm morphology (long abstinence time, regular cannabis intake, febrile episode …).
A migration-survival test (TMS) usually completes the diagnosis. It allows having an estimate of the number of spermatozoa able to be found in the uterus and able to fertilize the oocyte.
Spermoculture is often coupled with the spermogram to detect an infection that could alter spermatogenesis and cause morphological defects in spermatozoa.
Treatment to have a child
If an infection is detected during spermoculture, an antibiotic treatment will be prescribed. If exposure to certain toxic substances (tobacco, drugs, alcohol, and medicine) is suspected to be the cause of teratospermia, the elimination of toxic substances will be the first step in the management.
But sometimes no cause is found and the use of AMP will be proposed to the couple. The percentage of spermatozoa of normal form being a good indicator of the natural fertilizing capacity of the sperm, it constitutes a decision-making element, with in particular the migration-survival test, in the choice of the technique of MPA: intravenous insemination. Uterine (IUI), in vitro fertilization (IVF) or in vitro fertilization with intracytoplasmic injection (IVF-ICSI).