Updated by the Progyny Clinical Team — August 2025.
Azoospermia refers to a complete absence of sperm in the ejaculate. Non-obstructive azoospermia happens when there is no sperm because of abnormal sperm production.
Causes of Non-Obstructive Azoospermia
Genetic causes
Up to 10 percent of patients with non-obstructive azoospermia have genetic changes that lower sperm production. There are several genetic causes, including Y-chromosome microdeletions (changes on the Y chromosome) and karyotypic abnormalities (differences in the number or structure of chromosomes within a cell).
The most common karyotypic abnormality is called Klinefelter syndrome. It happens when a person has an extra X chromosome, which is typically linked to male physical traits.
Hormonal causes
For the testicles to produce sperm, they must be stimulated by pituitary hormones. The pituitary is a pea-sized gland at the base of the brain.
If these hormones are too low or missing, sperm production can’t happen. Exogenous steroids — whether taken now or in the past — can also interfere with the hormone system needed for sperm production. These are synthetic versions of testosterone, made outside the body rather than naturally produced.
Radiations and toxins
Exposure to toxic chemicals such as heavy metals, chemotherapy, and radiation therapy can damage sperm production. Because of this, sperm banking is often recommended before chemotherapy or radiation treatment.
Medications
Some medications can negatively affect sperm production. For example, testosterone supplements can disrupt the normal function of the reproductive system.
Varicoceles
Varicoceles are swollen varicose veins in the scrotum. They cause blood to pool in the scrotum, which can harm sperm production.
Treatments for Non-Obstructive Azoospermia
Hormone therapy can be used to treat hormone deficiencies. If you have an abnormal testosterone-to-estrogen ratio (T/E2), your provider may prescribe aromatase inhibitors (AIs). These medications lower estrogen levels by blocking aromatase, an enzyme in fat tissue that converts other hormones into estrogen. Using AIs can sometimes improve sperm concentration and motility.
Avoiding toxins and adjusting medications with your healthcare provider’s guidance can also improve sperm counts.
If azoospermia is linked to a varicocele, a urologist may recommend surgery to repair it and a testicular biopsy. Surgery ties off the affected veins and reroutes blood flow through healthy veins, which can sometimes restore sperm production. A testicular biopsy can also help determine the cause of azoospermia if it’s still unknown.
Pregnancy and non-obstructive azoospermia
Fertility specialists previously thought that people who have problems with sperm production could only build their family through donor sperm or adoption. However, testicular biopsies show that sperm can be found in about 50% of people with non-obstructive azoospermia.
The chance of finding sperm depends on the underlying cause. Testicular sperm often have lower motility, but they can be used in in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI).
A procedure called testicular sperm extraction with ICSI can be performed under local or general anesthesia. Sperm retrieved this way can be used during IVF. If non-obstructive azoospermia is caused by a genetic condition, genetic testing and counseling are recommended before moving forward with IVF.
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Disclaimer: The information provided by Progyny is for educational purposes only and is not medical advice. Always consult a qualified healthcare provider for medical guidance.