What Is Oligoasthenoteratozoospermia (OAT)?

Specimin cup
A semen analysis is the only way to test male fertility and sperm health. Steven Puetzer / Getty Images


Oligoasthenoteratozoospermia, or OAT, is a term used to describe semen which contains an abnormally low number of sperm, an abnormally low level of sperm with good motility, and an abnormally low level of sperm of a healthy shape.

You may recognize some of the prefixes from these more commonly known terms:

  • Oligozoospermia refers to lower than normal sperm counts
  • Asthenzoospermia refers to poor sperm motility
  • Teratozoospermia refers to poor sperm morphology, or shape

The term oligoasthenoteratozoospermia is used when all three factors are present.

The term idiopathic oligoasthenoteratozoospermia refers to the fact that the cause for these problems is unclear. Up to 30% of male fertility patients are said to have idiopathic OAT.

Pronunciation: OL-i-go-as-THE-no-TER-ah-to-zo-SPER-mee-ah (Or you can just say OAT -- much easier!)

More on male factor infertility:


Cavallini G. "Male idiopathic oligoasthenoteratozoospermia." Asian J Androl. 2006 Mar;8(2):143-57. http://www.ncbi.nlm.nih.gov/pubmed/16491265

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