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Abnormal sperm morphology: What does it mean?

Sperm morphology — the size and shape of sperm — is one factor that's examined as part of a semen analysis to evaluate male infertility. Sperm morphology results are reported as the percentage of sperm that appear normal when semen is viewed under a microscope.

Normal sperm have an oval head with a long tail. Abnormal sperm have head or tail defects — such as a large or misshapen head or a crooked or double tail. These defects might affect the ability of the sperm to reach and penetrate an egg. However, having a large percentage of misshapen sperm isn't uncommon. In addition, morphology alone doesn't indicate if you are fertile or not. A typical semen analysis also assesses:

  • Semen volume
  • Total sperm number
  • Sperm concentration
  • Vitality (percent alive)
  • Movement (motility)

An abnormal semen analysis also doesn't mean that you are infertile. Many men with low semen analysis values can still father children — it just might take longer. If you and your partner aren't able to conceive through sexual intercourse, assisted reproductive technology such as in vitro fertilization might be an option.

Last updated: May 20th, 2015

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