What Are Obstructive & Non-Obstructive Azoospermia?

What Are Obstructive & Non-Obstructive Azoospermia?

Most male infertility specialists classify problems with sperm production into two main categories:

  • Obstructive Azoospermia (OA)
  • Non-Obstructive Azoospermia (NOA)

Azoospermia is when a man doesn’t have any sperm in his ejaculate. The average man has 100–300 million sperm in his ejaculate. But if a man doesn’t have any sperm in his ejaculate, then this can make it difficult for couples to get pregnant. To diagnose azoospermia, we perform at least two semen analyses in our andrology lab.

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Obstructive Azoospermia

Obstructive azoospermia is caused when there is a plumbing problem that prevents the sperm from traveling out of the testes and into the penis. This condition is called a post-testicular cause of azoospermia, because a man’s testes produce enough sperm, but the transport system that allows sperm to leave the testes is abnormal.

Causes of Obstructive Azoospermia

Vasectomy: The most common cause of obstructive azoospermia happens when a man has had a vasectomy. The vas deferens, which carries sperm from the testicles to the urethra during ejaculation, has been purposefully cut in half during a vasectomy. Men choose to get vasectomies as a form of birth control.

Cystic fibrosis (CF): Cycstic fibrosis is a congenital pulmonary (lung) disease that can affect fertility. Nearly all men (95 percent) with cystic fibrosis (CF) don’t develop all or part of their vas and epididymis ducts on both sides of their testicles. This condition is called congenital bilateral absence of the vas deferens (CBAVD). Both the vas deferens and the epididymis help transport sperm from the testes into the penis. Although these transportation tubes are missing, sperm is still produced (spermatogenesis) in each testis. In fact, sperm production is normal in 90 percent of men with CF and CBAVD.

The exact cause of CBAVD is unknown. But researchers think that the same gene mutations that cause the lung and pancreas problems with CF also cause these ducts to not form. CBAVD does not affect sexual performance or ability to make love. In fact, most people are not aware that they have CBAVD until they can’t conceive and look for treatment from a male-reproductive expert.

Other Causes, which include:

  • Scarring from sexually transmitted infections.
  • Midline congenital cysts, which block the vas deferens from emptying into the urethra.
  • Narrowing of the opening of the penis from the foreskin (phimosis).

Obstructive Azoospermia Treatment Options

  • Vasectomy reversal: Most men who’ve had a vasectomy in the past can still conceive by having a vasovasostomy or vasoepididymostomy. These procedures are also called vasectomy reverasal.
  • Testicular sperm extraction (TESE): A testicular sperm extraction (TESE) procedure is another option for men who have had a vasectomy or who have another form of obstructive azoospermia. During this procedure, your doctor will make a small cut to expose the testicular tissue to retrieve sperm. Your doctor may also use a needle to aspirate the seminiferous tubules (testicular tissue) to get sperm.
  • Transurethral resection of the ejaculatory ducts (TURED): Transurethral resection of the ejaculatory ducts (TURED) is one option for men who have an obstruction where the vas deferens empty into the urethra at the ejaculatory ducts. TURED can remove this blockage and help sperm flow to the natural channels.
  • Circumcision: Men who have a narrow foreskin can have a circumcision.
  • Surgical correction for scarring: Some men have scarring from sexually transmitted infections (STIs) that can cause sperm to get blocked inside the ducts. Scarring can often be treating endoscopically. Your doctor will insert a scope through your urethra in the operating room while you are under general anesthesia.

What Is Non-Obstructive Azoospermia?

Non-obstructive azoospermia is a set of disorders that cause a man to produce abnormal sperm. All of these disorders cause either decreased production or no sperm production at all.

Causes of Non-Obstructive Azoospermia

Non-obstructive azoospermia can be sub-divided into pretesticular and testicular causes.

Pretesticular non-obstructive azoospermia

All pretesticular conditions disrupt the hormones a man needs for normal spermatogenesis (sperm creation). If a man has any of these conditions, this means he can’t produce healthy, normal sperm.

Causes of pretesticular non-obstructive azoospermia include the following:

  • Hypogonadotropic hypogonadism. This is a problem with the pituitary gland where it doesn’t make the hormones needed to create sperm or testosterone.
  • Hypothyroidism
  • Use of certain medications
  • Elevated estradiol
  • Kallman’s syndrome
  • Certain rare types of pituitary tumors

These conditions can usually be treated through oral or injectable medications.

Testicular non-obstructive azoospermia

If you have testicular non-obstructive azoospermia, this means that something is preventing your testes from creating normal sperm. Many things can cause testicular non-obstructive azoospermia. The conditions listed below make up the majority of non-obstructive azoospermia cases:

  • Varicoceles, or varicose veins in the scrotum, disrupt sperm production in the testicle (but rarely lead to azoospermia)
  • Bilateral undescended testicles or cryptorchidism
  • Testicular cancer
  • Gonadotoxins (such as radiation, chemotherapy, and some industrial chemicals that are toxic to the testes or gonads)
  • Immunologic causes, such as post-pubertal mumps orchitis. This is when a man who has already gone through puberty develops a mumps infection inside his testicle(s).
  • Sertoli-cell only syndrome (when the testis doesn’t have any sperm cells)
  • Incomplete development, where all of a man’s sperm can only reach a certain, incomplete stage of development
  • Genetic syndromes, such as Klinefelters (this is when a man has an extra X chromosome so they have XXY instead of XY)

Non-Obstructive Azoospermia Treatment

Regardless of what’s causing your non-obstructive azoospermia, the treatment approach is the same. We start with a semen analysis and male endocrine profile (blood work).

Treatments may include:

  • Drugs/Medications: If a man has a low bioavailable testosterone,* we usually start him on clomiphene citrate or clomid. The patient remains on this drug for four months, and we repeat another semen analysis. One in nine men will have their sperm return to the ejaculate after taking medication to return their testosterone to the normal range. Some men’s sperm don’t return to their ejaculate after taking medication. However, taking medication to normalize testosterone doubles the chances of finding sperm during a surgical sperm extraction procedure called microsurgical testicular sperm extraction (microTESE).
  • Microsurgical testicular sperm extraction (microTESE): We recommend microsurgical testicular sperm extraction (microTESE) for men who have adequate testosterone* during diagnostic testing. We also recommend microTESE for men who’ve taken medications to correct their testosterone for at least four months but still aren’t releasing any sperm during ejaculation. During microTESE procedures, doctors can find sperm approximately 70 percent of the time.

*Note: bioavailable testosterone is different from the total testosterone that many labs check.