OAT Syndrome: Reduced sperm quality

If the desire to have a child remains unfulfilled for a long time, many couples decide to have their fertility checked. If it turns out that the cause of the problem lies with the man, the diagnosis is often “OAT syndrome”. But what exactly does that mean?

Diagnosis of OAT Syndrome?

The term oligo-astheno-teratozoospermia syndrome (OAT syndrome) hides several individual symptoms, all of which describe a pathological change in the sperm. The symptoms can occur in different forms, resulting in three degrees of severity of the syndrome, which describe a slight, significant or severe limitation of fertility. The following guidelines apply to the OAT syndrome grade 1 (slight limitation of fertility):

• Oligo stands for “too little” and in this context describes a quantity of less than 20 million sperm per milliliter of male ejaculate.
• Astheno means “immobile” and is used to describe that less than 25 percent of sperm move quickly, or less than 50 percent move at all in a targeted manner.
• Terato stands for “malformed” and applies when less than 3 percent of the sperm are normally formed.

In OAT syndrome grade 2 (significant restriction of fertility) and 3 (severe restriction of fertility), the respective characteristics are more pronounced and the values ​​are correspondingly worse.

One can therefore only speak of OAT syndrome if all three symptoms occur simultaneously in a patient. In addition, it does not strictly represent a diagnosis, but only describes various symptoms. The causes behind the symptoms must first be diagnosed more precisely in order to initiate treatment. It is important, however, that the OAT syndrome is not to be equated with permanent and complete sterility. It is quite possible that their causes only limit fertility or are temporary.

Causes of OAT Syndrome

The reduced sperm quality, which is manifested by the OAT syndrome, can have various causes, which can either be related to spermiogenesis, i.e. the formation of healthy sperm, or their transport via the vas deferens:

• Malposition of the testicles : The testicles usually migrate from the abdomen into the scrotum in the first two years of life. If this is not the case and they remain in the abdominal cavity, the higher temperature inside the body can have a negative impact on the formation of healthy sperm or prevent it altogether. Febrile infections can temporarily have the same effect.
• Varicocele : Varicose veins in the testicles can cause overheating, which can have a negative impact on sperm quality.
• Hormone imbalances : When the sensitive hormonal balance and the interaction between the pituitary gland and testosterone is disturbed, this can produce the symptoms of OAT syndrome.
• Inflammation : Inflammation of the epididymis or prostate, for example due to mumps in childhood, can lead to a partial or complete blockage of the seminal ducts, which can impair sperm transport.
• External and environmental influences : Taking certain medicines or substances, such as anabolic steroids or drugs, stress, malnutrition, alcohol consumption, radiation, overweight or underweight and venereal diseases can also be factors that contribute to reduced sperm quality.

A detailed examination by the treating doctor is therefore very important to ensure effective treatment.

Treatment of OAT Syndrome

Since many of the causes for the occurrence of the OAT syndrome are only temporary, it can be treated very well in most cases. Due to the fact that the OAT syndrome combines several symptoms, there is no specific therapy that can be used for all patients. Rather, the actual cause of the OAT syndrome is first diagnosed and then treated in a targeted manner. Hormone disorders, for example, can be cured by administering hormone preparations, and inflammation can be treated by taking antibiotics or other anti-inflammatory agents. If the vas deferens is blocked, it can be opened surgically in some cases. If this is not possible, a testicular biopsy, the so-called TESE, is an option.

In order to identify the cause of reduced semen quality, the patient must undergo a detailed examination:

• Using a spermiogram , the sperm quality is first checked and the problematic factors are identified. This spermiogram should be repeated after a few weeks to rule out a short-term change in the situation.
• A semen test also examines the ejaculate for any chromosomal defects or hereditary diseases that can impair fertility.
• Hormone diagnostics are used to check the hormonal balance.
• An ultrasound scan is used to check the position of the testicles.
• A blood test for bacterial infections is intended to rule out inflammation of the prostate.

In most cases, these investigations can determine the exact cause of the problem and initiate effective treatment. If the cause cannot be clarified, one speaks of an idiopathic OAT. In this case, or if the sperm quality does not noticeably improve despite treatment, IVF or ICSI treatment is often necessary in order to still be able to have children.