Non-obstructive azoospermia refers to a condition when mature sperm is not found in the semen due to abnormal sperm production. The pituitary hormone stimulates sperm production in the testicles and if this hormone is absent or present in a very small amount, it affects sperm production in males.

Infections, hormonal imbalances, certain medications, and radiation can cause non-obstructive azoospermia. Sperm production can also be affected by varicose (swollen veins in the scrotum) and testicular failure (inability of the testicles to produce mature sperm) and can occur at different stages of the male reproductive cycle.

In some cases, a form of surgical sperm retrieval or SSR is used to retrieve mature and viable sperm. For non-obstructive azoospermia, the course of treatment is often Micro-TESE (Testicular Sperm Extraction), followed by In-Vitro Fertilization (IVF) with Intracytoplasmic sperm injection (ICSI).