Normal sperm have an oval head and a long tail, while abnormal sperm may have defects in the head or tail, such as a large or misshapen head or a twisted or double tail. Sperm abnormalities causes may significantly affect the ability of sperm to reach and penetrate an egg. However, having a large percentage of abnormal sperm is not uncommon, as only about 4% to 10% of sperm in a semen sample are standard, meaning that the vast majority of sperm may not be perfect when examined under a microscope.
Sperm morphology is not well understood, and results can vary in the same semen sample in the same laboratory and using the same scoring techniques. Most male fertility experts agree that the role of sperm morphology in predicting pregnancy is unclear and is a poor predictor of infertility unless nearly 100% of the sperm are abnormal.
What is a sperm abnormality?
Sperm is an essential component of the male reproductive system. It is a specialized cell responsible for fertilizing a female egg and initiating conception. Sperm cells are formed in the testes through spermatogenesis. During this process, undifferentiated cells in the testes divide and develop into mature, motile sperm cells that can fertilize an egg.
The term sperm abnormalities refers to an abnormality in the shape, size, or function of sperm, which can negatively affect male fertility and reduce the chances of successful conception. Sperm abnormalities can reduce the chances of successful fertilization and make it difficult for couples to conceive naturally. However, this does not mean that a person with abnormal sperm can never conceive; some advanced techniques and treatments can help achieve a successful pregnancy.
Types of sperm abnormalities
“The types of abnormalities vary depending on sperm abnormalities causes.”. Various sperm issues can affect fertility in men. These can range from problems with sperm count, motility, and shape. Some of the most common sperm issues that can affect fertility include the following:
- Low sperm count: This is a condition in which a male has less than 15 million sperm per milliliter of semen and can reduce the chances of successful fertilization.
- Poor sperm motility: Sperm motility refers to the ability of sperm to swim and move toward the egg. Poor or abnormal sperm motility can make it difficult for sperm to reach and fertilize the egg.
- Abnormal sperm shape: Sperm shape refers to the structure of the sperm. Abnormal sperm shape can lead to decreased fertility and an increased risk of miscarriage.
- Sperm adhesion: This condition in which sperm stick together and form clumps that can impair their motility and ability to fertilize an egg.
- DNA damage: A range of factors, such as age, environmental toxins, and specific medical conditions, can lead to DNA damage in sperm. This damage may lower the likelihood of successful fertilization and heighten the risk of embryo birth defects.
Types of sperm shape abnormalities
We will take a deeper look at sperm shape abnormalities and their relationship to the causes of sperm abnormalities to understand how they differ and what may cause fertility issues. A normal sperm should have an oval head, an intact midsection, and an uncoiled tail. Abnormal sperm may be as follows:
- Enlarged head: The head of the sperm is larger than usual and carries extra chromosomes, making it difficult for the sperm to fertilize the egg.
- Small head: The head of the sperm is smaller than usual, which indicates that the sperm may have a defect while interacting with the egg’s surface and may have less genetic material.
- Pinhead sperm: This type of sperm has a head that looks like a pin and contains little or no DNA. It is often associated with diabetes.
- Sperm with a pointed head: A cigar-shaped sperm head indicates the possibility of varicocele and may be due to constant exposure of the scrotum to heat.
- Sperm with a thin and narrow head are very rare and may be caused by DNA damage, varicocele, or a disorder during head formation.
- Spherical sperm have a round head rather than an oval one, aiding their ability to penetrate and reach the fertilization site.
- Headless sperm: This type has no head, genetic material, or chromosomes.
- Sperm without a tail: This type appears when an area of the testicle is infarcted.
- Nuclear gap issues: The sperm head has multiple small vacuoles instead of the typical two large vacuoles, which decreases the sperm’s ability to fertilize.
- Multi-headed sperm: Sperm can exhibit multiple heads or tails due to excessive exposure to chemicals, toxins, or elevated prolactin levels in the bloodstream.
- Sperm with a curled tail: Sperm with a curled tail cannot swim well due to damage to the tail, which indicates the presence of bacteria or excessive smoking.
Sperm Abnormalities Causes
Sperm abnormalities causes include a variety of factors, such as:
- Exposure to harmful environmental toxins
- Genetic factors
- Hormonal imbalance
- Lifestyle
- Medicines
- Infection
- Traumatizing the testicles
- No testicular prolapse
- Overuse of testosterone
- Varicose veins
However, sperm abnormalities causes are broadly categorized into two main groups:
Environmental factors and their impact on sperm health
- Testicular temperature: The more the testicles are exposed to heat, the more likely you are to have abnormal sperm.
- Exposure to chemicals: Constant exposure to chemicals due to work or the environment may lead to increased sperm abnormalities
- Infection: When left untreated, infections can affect sperm shape and quality.
- Varicocele: It is a health condition that causes abnormal enlargement and swelling of the scrotum, leading to abnormal sperm shape, movement, and low sperm count.
- Specific medical treatments: Certain treatments, such as radiation or chemotherapy, can cause defects in sperm structure.
- Lifestyle factors: Such as obesity, smoking, alcohol, and drug use, the risk of sperm abnormalities is significantly increased.
- Hormonal imbalance: Changes in the hormones produced by the testes, hypothalamus, and pituitary gland not only lead to low sperm count but also cause abnormalities in their shape.
Sperm abnormalities causes related to genetic and hereditary factors
The causes of genetic sperm abnormalities include DNA abnormalities, gene mutations, and deletions that impair sperm production or function. Here are the main genetic factors associated with sperm abnormalities:
- Chromosomal abnormalities: For example, Klinefelter syndrome (47, XXY), where males have an extra X chromosome, results in small testicles, low testosterone, and poor sperm production.
- Displacements: Structural rearrangements in chromosomes disable genes involved in spermatogenesis.
- Y chromosome microdeletions: Deletions in some areas of the Y chromosome (AZFa, AZFb, AZFc) are associated with no or few sperm.
- Single gene mutations.
- AURKC mutations: Causes spermatomegaly, where sperm are abnormally large and have multiple tails.
- DNAH1 mutations: Associated with sperm dysmotility.
- Mitochondrial DNA mutations: Defects in mitochondrial DNA can disrupt energy production, leading to poor sperm motility.
- Genetic syndromes: such as Noonan syndrome and Kartagener’s syndrome
Diagnosing these genetic factors often requires specialized tests such as karyotyping, Y chromosome microdeletion analysis, and mutation screening.
Methods for diagnosing sperm abnormalities
Several tests are available to evaluate sperm abnormalities causes, including those that assess motility, shape, and underlying genetic defects. Here are the most important diagnostic methods:
Semen analysis
Its purpose is to assess sperm count, motility, and shape. The parameters that are tested in this analysis:
- Sperm concentration (millions per milliliter)
- Motility (percentage of sperm moving)
- Shape and structure
- Semen volume and pH
- Presence of white blood cells (indicates an infection)
Sperm DNA fragmentation test
Its purpose is to detect DNA damage in sperm that can affect fertilization and embryo development. Some standard methods used in this test:
- Sperm Chromatin Structure Analysis (SCSA) evaluates the extent of DNA fragmentation in sperm, examining how DNA is organized within the sperm cell.
- TUNEL test: A highly sensitive and reproducible method for assessing the integrity of sperm DNA. It measures the number of breaks or scratches in sperm DNA and can be performed on at least 1000 sperm, even on sperm retrieved from a small testicular biopsy.
Y chromosome microdeletion test
Its purpose is to identify a deletion on the Y chromosome that impedes sperm production and the central regions tested: AZFa, AZFb, and AZFc.
Karyotype test
It aims to detect chromosomal abnormalities, such as Klinefelter syndrome (47, XXY), by analyzing the number and structure of chromosomes.
Hormonal test
- Its purpose is to evaluate hormonal imbalances that affect sperm production. The main hormones that are tested:
- Follicle Stimulating Hormone (FSH)
- Luteinizing hormone (LH)
- Testosterone
- Prolactin hormone
CFTR gene mutation test
It aims to identify the mutations that cause congenital bilateral absent vas deferens (CBAVD). Its diagnostic significance lies in men with obstructive azoospermia.
Quantitative assessment of intracellular reactive oxygen species (ROS)
Its purpose is to measure oxidative stress in semen, which can damage the DNA and membranes of sperm.
Sperm antibody test
is a laboratory test used to detect anti-sperm antibodies in blood, semen, or vaginal mucosal secretions. The test aims to determine the types of these antibodies and how they affect sperm clotting. This test is recommended to evaluate a man’s fertility and identify possible causes of delayed conception or male infertility.
Ultrasound imaging
Its purpose is to detect structural abnormalities in the genitals, such as varicocele and obstructions. Techniques used:
- Scrotal ultrasound examines the testicles and surrounding tissue for abnormalities or swellings.
- Transrectal ultrasound (TRUS): Used to assess the integrity of the prostate and seminal vesicles, helping to identify any blockages or abnormalities in these organs.
Advanced genetic testing
The purpose is to identify rare genetic mutations that affect sperm formation, such as:
- Whole Exome Sequencing (WES) is a precision genetic test that identifies DNA changes associated with protein-coding genome regions (exomes). It enables rapid and reliable disease diagnosis.
- Single nucleotide polymorphism (SNP) testing: A sample of the patient’s DNA is isolated from a blood sample. The lab then uses this sample to identify genetic variations known as single nucleotide polymorphisms (SNPs).
Testicular biopsy
The purpose is to determine whether sperm production is occurring within the testicles, which is done by taking a small tissue sample for microscopic examination. These tests help diagnose sperm abnormalities causes and guide appropriate treatment options, such as assisted reproductive technologies (ART) such as IVF or ICSI.
How to treat sperm abnormalities and improve fertility
Males with sperm abnormalities can still have children in most cases. However, they typically need medical assistance, as the treatment depends on the sperm abnormalities causes. Some common treatments for sperm abnormalities include the following:
- Medicines: Especially those involved in the treatment of hormonal imbalances and inflammation.
- Surgery: To treat congenital abnormalities or if there are issues such as varicocele.
- Assisted reproductive technologies (ART) to help conceive: Artificial insemination (IVF), intracytoplasmic morphologically selected sperm injection (IMSI), and intracellular sperm injection (ICSI) are advanced treatment options that help insert a viable sperm into an egg to facilitate fertilization.
- Lifestyle changes: By managing stress, eating a balanced diet, and exercising to improve sperm quality. You should also avoid excessive exposure to environmental toxins and heat in the testicles to maintain proper sperm shape and size.
- Avoid using testosterone steroids, excessive tobacco use, alcohol, or drugs.
- Reduce the amount of caffeine consumed and lose weight if necessary.
- Avoid hot tubs and minimize stress.
- Wear loose cotton pants.
It takes about three months to produce and transport new sperm, so any dietary or lifestyle changes will take time before they show tangible results. Because of the effect of aging on sperm quality, some doctors recommend freezing sperm early in life if a man plans to delay having children.
When the sperm abnormalities causes are multiple and complex, it becomes imperative to seek medical care while planning a pregnancy. Bimaristan Center in Turkey can be visited for specialized medical consultations. The center offers semen analysis services to accurately diagnose the causes of abnormalities, enabling doctors to provide appropriate treatments to improve your chances of conceiving.
An abnormal semen analysis does not mean that the patient is infertile. Many men with low semen analysis values are still able to have children, but it may take longer. Suppose you and your partner are unable to conceive through regular intercourse. In that case, you can contact the specialists at Bimaristan Center to diagnose the sperm abnormalities causes and get help in choosing the right assisted reproductive technology for your case.
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