Azoospermia means no sperm are found in the ejaculate after the semen sample has been properly processed and the centrifuged pellet is examined. It does not always mean the testes make no sperm. In obstructive azoospermia, sperm production may be normal but a blockage prevents sperm reaching semen. In non-obstructive azoospermia, sperm production is severely impaired, although small focal areas of sperm production can still exist. The distinction is crucial because treatment ranges from reconstruction or epididymal/testicular sperm retrieval to micro-TESE and IVF/ICSI.

What exactly is azoospermia?

Azoospermia is a laboratory diagnosis of complete absence of sperm from the ejaculate. It should be distinguished from aspermia, where there is little or no antegrade ejaculate, and from cryptozoospermia, where rare sperm are found only after semen centrifugation and careful examination of the pellet. Finding even a few ejaculated sperm can change fertility options and may avoid surgical retrieval in some men.

Two major types of azoospermia

How azoospermia is confirmed

The laboratory should centrifuge the semen and carefully examine the pellet for rare sperm. If none are found, a repeat semen analysis is required to confirm the finding. In a newly discovered azoospermia, evaluation should begin promptly rather than simply waiting several months, because classification affects genetic testing, fertility planning and whether sperm retrieval is likely to help.

Causes of obstructive azoospermia

• Congenital bilateral absence of the vas deferens, often associated with CFTR variants.
• Previous vasectomy.
• Epididymal blockage after infection, inflammation or surgery.
• Injury to the vas deferens during inguinal, scrotal or pelvic surgery.
• Ejaculatory duct obstruction in selected men, often associated with low semen volume and abnormal pH.

Causes of non-obstructive azoospermia

• Genetic conditions such as Klinefelter syndrome.
• Y-chromosome microdeletions.
• Previous undescended testes or severe testicular damage.
• Chemotherapy or radiotherapy.
• Primary testicular failure with high FSH.
• Severe suppression from exogenous testosterone or anabolic steroids; recovery may be possible but can take time.
• Hypogonadotropic hypogonadism, where targeted hormonal therapy may induce spermatogenesis.
• Idiopathic NOA when no clear cause is identified.

Tests used to classify azoospermia

• Repeat semen analysis with pellet examination.
• Detailed genital examination: testis size/consistency, epididymis, vas deferens and varicocele.
• FSH and testosterone; LH, prolactin and estradiol selectively.
• Karyotype and Y-chromosome microdeletion testing in suspected impaired sperm production.
• CFTR testing when congenital absence of the vas deferens is suspected.
• Scrotal or transrectal ultrasound only when clinical findings indicate it.

Treatment options

Can sperm still be found in non-obstructive azoospermia?

Yes, in selected men. Sperm production in NOA can be patchy. Micro-TESE uses an operating microscope to search for seminiferous tubules more likely to contain sperm while limiting unnecessary tissue removal. Success depends on the underlying biology and cannot be predicted perfectly by FSH or testicular size alone.

Azoospermia and fertility timing

The male plan should be coordinated with the female partner’s age and ovarian reserve. In OA, sperm retrieval is usually reliable, so retrieval may be scheduled before or around the IVF cycle. In NOA, sperm may not be found; couples should discuss whether micro-TESE is performed before ovarian stimulation with sperm frozen if found, or synchronised with egg retrieval depending on centre practice and priorities.

How azoospermia is classified in clinic

The first task after confirming azoospermia is to decide whether sperm are being produced but blocked, or whether sperm production itself is severely impaired. Examination of testicular size and consistency, whether the vas deferens can be felt, previous vasectomy/groin surgery/infection, semen volume and pH, and FSH/testosterone all contribute. No single blood test can reliably make the distinction in every man.

Men with obstruction often have normal-sized testes and relatively normal FSH, whereas non-obstructive azoospermia more often has smaller testes and higher FSH. There is important overlap. Low-volume acidic semen can point toward ejaculatory-duct or seminal-vesicle problems, while absent vas deferens raises the possibility of CFTR-related congenital obstruction.

Classification should come before a sperm-retrieval procedure. It determines whether reconstruction may be possible, whether epididymal or testicular retrieval is appropriate, whether micro-TESE is needed, and which genetic tests should be completed before treatment.

A man with azoospermia may have normal erections, orgasm, ejaculation and semen appearance. There is usually no way to tell by looking at the semen whether sperm are absent. This is why laboratory confirmation and a structured male-reproductive examination are essential before conclusions about fertility are made.

The cause also matters for the man’s health, not only fertility treatment. Azoospermia can occasionally be the first clue to a genetic condition, endocrine disorder, previous testicular injury or congenital absence of reproductive structures. A complete evaluation therefore remains worthwhile even when the couple is already planning IVF/ICSI.

What to bring for consultation

Bring these if available:

• Two semen analysis reports if available, including whether the pellet was examined.
• Semen volume and pH if reported.
• FSH, LH and testosterone reports.
• Karyotype, Y-microdeletion or CFTR reports if already done.
• Scrotal ultrasound or previous surgery records.
• History of undescended testis, vasectomy, hernia surgery, infections, cancer treatment or testosterone/anabolic steroid use.
• Partner’s age, ovarian reserve and IVF plan if treatment is already underway.

FAQs

Related reading

• Obstructive Azoospermia
• Non-Obstructive Azoospermia
• Cryptozoospermia Explained
• High FSH in Male Infertility
• Genetic Testing in Male Infertility
• Urologist in Latur

References

• World Health Organization. WHO laboratory manual for the examination and processing of human semen, 6th ed https://www.who.int/publications/i/item/9789240030787
• European Association of Urology. EAU Guidelines on Sexual and Reproductive Health: Male Infertility. 2026 https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility
• American Urological Association/American Society for Reproductive Medicine. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline (2020; Amended 2024) https://www.auanet.org/documents/Guidelines/PDF/2024%20Guidelines/Male%20Infertility%20Unabridged%20Final.pdf