THE SHAPE OF THE SPERM

The final part of the semen analysis is the microscopic examination for structure, of the sperm. In a normal specimen as many as 30 % of the sperm may be abnormal. Keep one thing in mind, there is no relationship between abnormal sperm and abnormal pregnancy. Abnormally shaped sperm CANNOT fertilize the egg.

The normal sperm has an oval head with a long tail. Abnormal sperm may either have a very large round head or an extremely small, pinpoint head or have two heads. The sperm may be bent at the neck and misshapen, and the tails may have kinks and curls in them. None of these horrifying looking sperm (which are present in large numbers even in normal ejaculate) is indicative of any genetic problem. However, such abnormally shaped sperm are not capable of fertilization.

There is a strong relationship between structure of the sperm and their motility. In general, abnormal sperm exhibit poor motility and normally sperm exhibit good motility. One advantage of checking the structure is that if the specimen is more than two hours old and its motility is therefore difficult to interpret, the structure is another measurement which may help to determine what percentage of the sperm are actually capable of fertilization. The female cervical mucus tends to filter out the misshapen sperm and those with poor motility.