Difference Between Azoospermia and Oligospermia in Male Infertility

Here are the known causes of oligospermia and azoospermia: 

• Chromosomal abnormalities such as Klinefelter’s syndrome, Kallmann’s syndrome and Kartagener syndrome.
• Hormonal imbalances due to any alteration in the pituitary gland and hypothalamus. These hormones play a part in sperm production.
• Medications such as ulcer medications, antibiotics, antifungal medicines, testosterone replacement therapy, or chemotherapy drugs.
• Retrograde ejaculation can also be a cause of such condition when semen instead of flowing out of the penis reverses back to the bladder.
• Anti-Sperm antibodies can kill sperm cells by mistakenly identifying them as harmful invaders, which subsequently affects the sperm count.
• Environmental toxins, including exposure to chemicals, heavy metals or radiation.
• Sertoli-cell-only syndrome due to which no sperm is produced by the testicles.
• Undescended testicles occur when, during fetal development, the testicles do not descend from the abdomen to the scrotum. 
• Anorchia is the absence of testicles which can also lead to azoospermia.
• Obstruction can be a reason of low or no sperm count. It can be caused by a blockage in the duct or medical conditions, such as cystic fibrosis.
• Trauma or Injury as a consequence of vasectomy, scrotal surgery, hernia repair surgery, etc.