By Mayo Clinic Staff
Sperm morphology refers to the size and shape of sperm. It's one factor that healthcare professionals look at as part of a semen test. The test helps show if you're able to have children, called fertility.
In the lab, technicians look at sperm under a microscope to see if the sperm meet strict standards. The lab reports the percentage of sperm that meet those standards.
Sperm most often have a smooth, oval head with a long tail. Some sperm have heads or tails that aren't typical. This may include large or misshapen heads or crooked or double tails. These issues may affect whether the sperm can reach an egg and enter it.
Having many sperm with these issues is somewhat common. In most semen samples, only around 4% to 10% of the sperm meet strict standards. That means most sperm don't look perfect under the microscope.
Most fertility experts agree that the role of sperm morphology in predicting pregnancy is not clear. And it doesn't predict lack of fertility well. Also, sperm tests don't look at the cause of sperm morphology. The cause may affect fertility.
Besides sperm morphology, a semen test looks at other factors, including:
- Semen volume.
- Total sperm number.
- Sperm concentration.
- Movement, called motility.
Having semen that doesn't meet strict standards doesn't mean that you can't have children. Many people with low semen values can have children. But it may take longer, or you may need help from a healthcare professional. If you and your partner can't get pregnant through sexual intercourse, you might think about assisted reproductive technology such as in vitro fertilization.