Semen analysis the first step to uncovering the cause of infertility.
Couples who are experiencing difficulty in conceiving often have problems which include abnormal sperm production or function. In fact, these problems occur in 35-50% of the cases of infertility. Because of this, our lab staff performs a routine procedure to examine the sperm through a test called a semen analysis.
Semen samples are evaluated for their volume, sperm concentration, sperm motility, progression and sperm morphology. The volume and the concentration, when multiplied together, tell us how many total sperm there are in the sample. It is important to also know how many sperm are motile or moving. This is expressed as a percent of the total sperm count. We also know from years of experience that it is important for the sperm to move with some speed in a forward direction. This is called forward progression and is expressed as a number between 1 (slow) and 4 (fast).
One of the least understood characteristics of a semen analysis is sperm morphology or shape.
Each sperm is manufactured by cells in the testes and is composed of three parts; the head, the tail and the midpiece. These parts are all very important for a sperm to be able to swim to an egg and to penetrate its surrounding layers. Sometimes one or more of these parts is not formed perfectly by those cells that manufacture sperm in the testes and it affects the sperm’s ability to swim to and to penetrate the layers of the egg.
The head is normally oval in shape and contains all of the chromosomes that the father will contribute to an embryo. An abnormally-shaped sperm can be very small, very large or odd-shaped. This can mean that it has the wrong number of chromosomes or is incapable of binding with and entering the egg.
The tail is a long, whip-like structure that must propel the sperm from the vagina, where it is deposited by the man, through the mucous of the cervix, across the uterus and into the Fallopian tubes to the egg. Once it arrives at the egg, the sperm must still have sufficient tail movement to penetrate the layers of cells and membranes around the cell material of the egg. The tail is sometimes very short or curled in a way that prevents it from providing the motility required.
The third feature of the sperm is the mid-piece. This structure contains important organelles within it that provide energy to the sperm so the tail can propel the sperm to the egg. It also contains structures that allow the chromosomes of the egg and the sperm to organize and divide properly once the sperm has penetrated the egg. The midpiece can be missing or odd-shaped. An irregular mid-piece may indicate an inability to swim to the egg or a loss of the ability of that sperm to penetrate or to fertilize an egg.
The morphology is expressed as a percent normal. That means that, of the total count, there is a percent that have normal shape. Even the most fertile man has a percent of his sperm that have abnormal shape. The World Health Organization (WHO) states that a 30% or greater normal morphology in a semen sample is considered to be in the normal range of the general population.
All of the features of the sperm are examined at Ovation Fertility Austin by our experienced staff using state of the art phase contrast microscopes. This allows us to perform an accurate and thorough analysis. This information is given to the couple’s physician so that a complete work up can be performed.