Sperm Info and Prep

What is a sperm cell?

Sperm are the male gametes, or sex cells. Each sperm consists of a few main components:

Acrosome: contains enzymes that the sperm needs to penetrate the egg's shell/membrane.
Nucleus: contains the sperm's DNA, which will be deposited into the egg at fertilization.
Neck: contains mitochondria, which provides the energy that the sperm needs to swim through the female reproductive tract to get to the egg.
Tail: allows the sperm to move through the female reproductive tract to get to the egg.

Sperm are produced in the male testicles with the help of the hormone testosterone. Sperm production begins at puberty and continues throughout a male's lifetime. Sperm travel from the testicles through the epididymis, vas deferens, ejaculatory duct, and urethra before exiting the body through the tip of the penis. Along the way, sperm are coated in a fluid known as semen, so an ejaculate contains both sperm and semen. In order to fertilize an egg, the sperm must travel through the female reproductive tract and fertilize an egg inside the Fallopian tube shortly after the female has ovulated. The sperm completes a process known as capacitation inside the female reproductive tract, which makes it able to achieve fertilization.

The nucleus of each sperm contains 23 chromosomes. This is 1/2 the amount of chromosomes that any other cell in the body contains (except an egg in females). Thus, sperm are known as haploid cells. When fertilization occurs, the sperm's DNA combines with the egg's DNA to make a cell with 2 sets of chromosomes (diploid).

How do sperm determine the gender of an embryo?

One of the sperm's 23 chromosomes is its sex chromosome, which can be either an X or Y chromosome. If a sperm with a Y chromosome fertilizes an egg, the embryo will genetically be a male (XY). If a sperm with an X chromosome fertilizes an egg, the embryo will genetically be a female (XX). All eggs contain only an X chromosome, so the sperm determines the gender of the embryo.

What is a semen analysis?

A semen analysis is just that: an analysis of semen/sperm. Semen analyses are important because they can determine the following:

  1. If your sperm parameters are within normal ranges (count, motility, morphology, etc.)
  2. 2. If your sperm are capable of achieving a fertilization naturally, or if assisted reproduction is needed
  3. 3. If there is any male-factor infertility that needs to be addressed and treated
  4. 4. If sperm is not present (for example, in the case of a vasectomy)

Multiple semen analyses should be completed at different times since sperm parameters can change daily.

Semen analyses measure some or all of the following:

  1. Sperm count: how many sperm are in an ejaculate
  2. Sperm concentration or density: how many sperm are in a particular amount of semen (1 mL, for example)
  3. Motility: the percentage of sperm moving in a semen sample. Forward progression refers to how many sperm are moving forward/normally
  4. Vitality: the percentage of live sperm in a semen sample
  5. Morphology: how many sperm are normal in appearance
  6. Agglutination: how many sperm are stuck together in clumps
  7. Debris: how much other "stuff" (blood cells, round cells, etc.) is in the semen sample
  8. pH: how acidic or basic the sample is
  9. Volume: how much fluid is in the sample
  10. Viscosity: how thick the sample is
  11. Appearance: the color and opacity of the sample
  12. White blood cell count: how many white blood cells are present in the sample

How is sperm prepared?

Before an intrauterine insemination (IUI), ICSI, or conventional insemination can occur, a sperm sample must be prepared. Sperm samples can either be fresh (collected just prior to the preparation) or frozen (thawed just prior to the preparation).

Before any preparation occurs, the semen/sperm undergo a quick analysis to ensure that sperm are present and motile and that everything appears normal.

The primary goal of a sperm preparation is to separate the viable, motile sperm (the "good" sperm) from the other "stuff" in the ejaculate (dead sperm cells, white blood cells, mucus, etc.) so that only the good sperm are used for the insemination. During natural fertilization, the female reproductive tract traps the other "stuff" so that only the good sperm can make it to the egg.

At Pelex, we utilize the ZyMot device to prepare sperm for IUI and ICSI/IVF. This device uses a small filter to separate motile sperm from debris and dead or immotile sperm using the “swim up method.” The motile sperm are able to swim through the pores in the filter and are collected for insemination, while the debris and other sperm remain trapped below the pores. Here is a video from the ZyMot website displaying how the device is used: https://youtu.be/S_MiBX8tfng

Can sperm be frozen?

Absolutely. There are many instances where sperm may need to be frozen, including:

  1. A male partner cannot be present on the day of insemination.
  2. A male partner cannot produce a sample on the day of insemination.
  3. A male partner is undergoing treatment, such as radiation, and would like to preserve sperm prior to the treatment.
  4. A fresh sample does not contain enough good-quality sperm, so multiple samples may need to be utilized.
  5. Donor sperm is being used for insemination.

The process of freezing sperm involves mixing the semen sample with a specialized freezing media and slowly cooling the sample. After about 30 minutes, the sample is plunged into liquid nitrogen and is stored there for future use. When you are ready to use the frozen sperm, it can be thawed prior to insemination. Typically, the sperm is not damaged in the freezing and thawing processes.

Can I Use Donor Sperm?

Yes. Donor sperm can either be from an anonymous (from a sperm bank) or known donor. It’s important that you have your donor chosen and have sperm at your IVF clinic prior to the start of your IUI or IVF cycle. The donor sperm will need to be thawed prior to insemination. It’s also important to make sure that your sperm donor has completed infectious disease screening and, if possible, carrier screening for genetic diseases, as these can be passed onto offspring. 

What is a TESE/TESA/MESA/microTESE?

A TESE (testicular sperm extraction) is a surgery that collects sperm from the seminiferous tubules (in the testicles) if there are no viable sperm present in an ejaculate. This procedure is common for men with very low sperm counts, men who have had a vasectomy, or men with blockages in their reproductive tract that prevents the sperm from exiting the body. A TESE cannot help to obtain sperm if there is no sperm being produced. Your doctor can help determine if a TESE is a good option for you.

A TESE procedure is done with a local anesthetic, so you are awake for the procedure but should not feel pain once the anesthetic is administered. During a TESE, a small incision is made into the testicle(s). A device called a biopsy gun (it sounds scary but it's not too bad) is then inserted through the hole and into the testicle. The biopsy gun is able to collect a small sample of the seminiferous tubules inside the testicle(s). The hope is that these tubules contain viable sperm. There will likely be a few samples taken before the tissue is analyzed under a microscope. The tubules are processed using a needle, which opens the tubules so the sperm can swim out of them. The sample is then analyzed under a microscope for the presence of sperm. It is up to the embryologist to decide if another sample is needed, or if there is enough viable sperm present to inseminate a proper number of eggs. Once all of the samples have been obtained, the sample is placed in a sterile, labeled tube until it is time to inseminate the eggs. Additionally, TESE sperm can be frozen and thawed later, though fresh TESE samples tend to yield better results than thawed TESE samples.

A TESA (testicular sperm aspiration) is similar to a TESE, but a needle is inserted into the seminiferous tubules and the sperm are aspirated (sucked out) of the tubules using the needle and a syringe. This is also typically performed under a local anesthetic, so you will be awake for the duration of the procedure.

A MESA (microsurgical epididymal sperm aspiration) procedure is similar to a TESA, but the sperm is aspirated from the epididymis rather than the seminiferous tubules. The needle is simply routed into the epididymis rather than the seminiferous tubules to extract sperm. 

A typical recovery time after and TESE/TESA/MESA is around 7 days, though many men recover in much less time. Medications may be prescribed to treat any pain. TESEs and TESAs both do not require stitches due to the small size of the incision.

Another procedure, known as a microTESE, can also be performed. This procedure is typically done under a general anesthetic, so you are asleep for the procedure. The incision is larger for a microTESE so that the doctor can physically see the seminiferous tubules. If the tubules appear swollen, that typically means that sperm is present inside of them. These are the tubules that are removed and analyzed under the microscope for the presence of sperm. After the procedure, the incision is stitched up. Recovery time is typically around 10 days. Icing, pain medications, and rest are recommended to help with the recovery.


An overview of sperm anatomy | Legacy (givelegacy.com)

Semen Analysis: Sperm Count Test Procedure and Results (healthline.com)

Andrology: Sperm Motility & Progression (fertilitycenter.com)

Normal Sperm Count: Understanding Your Semen Analysis (healthline.com)

Semen Analysis Report: Purpose, Procedure, & Results (webmd.com)

MicroTESE, TESE Procedure, & TESA Procedure | University of Utah

How it works: The ZyMōt Multi (850μL) – ZyMōt Fertility (zymotfertility.com)

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