Urology
Azoospermia and Oligospermia
Zero sperm count or low sperm count can affect your fertility. Our urologists specialize in male reproductive health.
Medically reviewed by Marc Dall'Era, M.D. on April 06, 2026.
Helping Couples with Low or Zero Sperm Count Conceive
If you and your partner have difficulty conceiving after a year of trying, you may want to ask your doctor about fertility testing. Urology experts at UC Davis Health diagnose and treat conditions affecting sperm production and movement in the male reproductive system.
Even if you are diagnosed with low sperm count or zero sperm count, you may be able to have biological children. UC Davis Health helps couples conceive with advanced fertility treatment and assisted reproductive technology, including sperm retrieval.
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What Is Azoospermia and Oligospermia?
Sperm is a building block of life. It’s produced in your testes and combines with fluid in your reproductive tract to become semen. Semen is ejaculated through your penis during intercourse to fertilize a woman’s eggs.
Azoospermia, also known as zero sperm count or no sperm count, is the absence of sperm in your ejaculate. It affects up to 15% of men who have infertility. There are two common types of azoospermia:
- Obstructive azoospermia: Obstructions in your reproductive tract block the movement of sperm.
- Non-obstructive azoospermia: Hormonal or genetic conditions affect your sperm production.
Another condition affecting male infertility is oligospermia, also known as oligozoospermia or low sperm count. Oligospermia is defined as ejaculate having a sperm concentration of less than 15 million per milliliter.
Signs and Symptoms of Low Sperm Count and No Sperm Count
Other than a lack of pregnancy, there are often no signs that you ejaculate fewer sperm than needed for successful conception.
Common Symptoms
If you have symptoms, they may include:
- Decreased facial and body hair
- Erectile dysfunction
- Low libido (sex drive)
- Small testicles
Emergency Symptoms
Symptoms such as a lump on your testicle or a fever can indicate serious conditions, such as cancer and infection. Get immediate help if you suspect testicular torsion, an emergency condition that can cause the loss of a testicle. Symptoms of testicular torsion may include:
- Blood in your semen
- Change in scrotum skin color
- Lump on your testicle
- Nausea or vomiting
- One testicle higher than the other
- Sudden, severe pain in one testicle
- Swelling on one side of your testicle
Causes of Low Sperm Count or Zero Sperm Count
Azoospermia and oligospermia share some similar causes. But it’s important to know that azoospermia represents a lack of sperm production or blockage. Sperm is present but reduced with oligospermia.
Blockage
A blockage prevents the movement of sperm in your reproductive system and causes azoospermia. The blockage may be present at birth or acquired later.
Genetic Conditions
Differences in your genetic makeup affect the production of sperm.
Environmental toxins
Smoking and exposure to heavy metals, pesticides and radiation may cause male infertility.
Heat
Scrotal heat from fever and swollen testicular veins can affect your sperm production. Wearing tight clothing and repeated exposure to heat at work or in a hot tub are also factors.
Hormone Imbalance
Your testicles don’t get adequate hormonal signals from your brain to produce enough sperm.
Infection
Urinary tract infections and sexually transmitted infections affect reproductive health.
Medication
Certain prescription and recreational drugs can impact fertility.
Diagnosis and Testing for Azoospermia and Oligospermia
Our experts in male urology use a combination of traditional examination and innovative testing to diagnose male infertility. Your urologist will perform a physical exam, which may include an examination of your genitalia and a digital rectal exam. Other tests you may undergo are:
Biopsy
A biopsy is a minimally invasive surgical procedure to remove a tissue sample from the scrotum.
Genetic Testing
Genetic testing detects conditions such as an extra X chromosome in men who have Klinefelter syndrome.
Hormone Evaluation
Hormone evaluation helps us differentiate between obstructive and non-obstructive azoospermia and choose the appropriate treatment.
Semen Analysis
In order to test your sperm levels, you will need to provide several samples of ejaculate.
Ultrasound
Scrotal and transrectal ultrasound create a detailed picture of your reproductive system using sound waves.
Urinalysis
A urinalysis checks for blood, infection and other indicators of disease.
Zero or Low Sperm Count Treatments
UC Davis Health can help you manage azoospermia and oligospermia. Our leading-edge treatments may improve your chances for conception.
Hormone Therapy
Controlling hormone levels may help stimulate sperm production.
Sperm Retrieval
Microdissection testicular sperm extraction uses a surgical microscope to locate small amounts of sperm. The sperm is extracted for male fertility preservation.
Surgical Correction
Surgery repairs blockages in the reproductive tract.
Preventing Male Infertility
You may not always be able to prevent male infertility, but there are steps you can take to reduce your risk.
Avoid Certain Medications
Talk to your physician about medication that may affect your fertility. Only use marijuana, opioids, testosterone supplements and anabolic steroids under a physician’s supervision.
Eat a Balanced Diet
Eating a balanced diet and limiting alcohol consumption supports your overall health.
Moderate Heat Exposure
Skip tight clothing and limit your use of hot tubs and saunas.
Reduce Environmental Toxins
Stop smoking and limit your exposure to heavy metals and radiation.
“Male Infertility,” National Institutes of Health, National Library of Medicine, https://www.ncbi.nlm.nih.gov/books/NBK562258/
Approximately
1 in 100Men have azoospermia (zero sperm count.)
Up To
15%Of men with infertility have azoospermia.
Source: National Institutes of Health, National Library of Medicine: Azoospermia
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