Sperm Morphology – What is it & How Does it Affect Fertility
huangyan Apr 13, 2023
When a couple faces difficulty in getting pregnant or having a successful pregnancy, a fertility specialist will check both partners. They will check the overall health and the health of the reproductive organs of both males and females. When it comes to the male partner, sperm morphology is very important for a successful pregnancy – be it natural or through fertility treatments.
What is Sperm Morphology?
The sperm has a particular shape and size to help it travel fast and penetrate the egg, thus fertilizing it. As per studies, you can find around 39 million sperm per ejaculation. Among these millions of sperms, many will be irregular in shape or size, without a proper head or length. That is ok.
It takes just one sperm to fertilize an egg. For this one sperm to reach and fertilize successfully, millions of sperm travel up the fallopian tube, and the strongest of them all succeeds. So, out of these millions of sperm, you need just a small percentage to be of the right shape and size, in other words, the right sperm morphology for a successful pregnancy.
When a couple is having difficulty conceiving, a routine semen analysis will help understand sperm morphology. A sample of semen is studied closely under a microscope to understand the morphology. A healthy sperm must have an oval-shaped head and a midpiece and a tail.
If this head does not have a proper shape or if there is no tail, then the sperm is abnormally formed. The lack of a proper head will affect the sperm’s ability to penetrate the egg for fertilization. The lack of a tail will affect its ability to swim up the fallopian tubes, to reach the egg.
Sperm Morphology Range
The required sperm morphology normal range is about 4 - 14% only. Yes, you read that right. You need just around 14% of the sperm to be of the right shape and size for a successful pregnancy.
When sperm morphology is above 14%, according to Kruger criteria, the probability of fertility is very high. If it is below 4%, meaning the percentage of healthy sperm is less than 4%, it is an abnormal sperm morphology, which can take longer to achieve pregnancy. The WHO also recommends a similar range.
Your fertility doctor can help identify the reason behind the abnormal sperm morphology and help rectify it with suitable treatments.
Reasons for Abnormal Sperm Morphology
Every male will have a certain percentage of abnormally formed sperm. The range will vary from person to person depending on the following factors:
Testicular Temperature – Higher your testicles’ exposure to heat, the higher the chances of abnormal sperm.
Chemical Exposures – If you are constantly exposed to chemicals due to your work or the environment you live in, it can result in a higher range of abnormal sperm morphology
Infections – Infections when left untreated can affect the sperm shape and quality.
Genetics – Abnormal sperm morphology can be a genetic trait too. Unless a person tests their semen sample, abnormal sperm morphology will g,o unnoticed. So this can be tricky to identify.
Types of Sperm Morphology
Let’s take a deeper look into sperm morphology to understand how it can differ and which can cause fertility issues. A normal sperm morphology should have an oval head, an intact middle piece, and a tail that does not coil. Abnormal sperm can be as follows:
1. Macrocephaly
The sperm head is bigger than normal
Head carries extra chromosomes
Sperm might have trouble fertilizing an egg
Could be genetic
2. Microcephaly
Sperm head is smaller than normal
Sperm might have defective acrosome
Might have lesser genetic material
3. Pinhead Sperm
The sperm head appears like a pin
Might contain very little or no DNA material
Might indicate diabetes
4. Tapered Head Sperm
The sperm head is shaped like a cigar
Indicates a possibility of Varicocele
This could be due to constant scrotum exposure to heat
The head might contain abnormal chromatin
The head might contain abnormal packaging of the DNA material
Chances of an abnormal number of sperm chromosomes called aneuploidy
5. Thin Narrow Head Sperm
Very rare
A variation of the tapered-head sperm
This could be due to broken DNA material, Varicocele, or disruption in the head formation
6. Globozoospermia
Sperm will be round-headed instead of oval
Indicates an absence of acrosome or important parts of the head
Sperm can break down prematurely
7. Headless Sperm
Known as acephalic or decapitated sperm
Has no head, genetic material, or chromosomes
8. Tail-Less Sperm
Known as acaudate sperm
Seen during the death of most cells in an organ
9. Nuclear Vacuoles
The sperm head has two or more large vacuoles (bubbles that look like cysts)
Has multiple small vacuoles in the head
Might have low potential for fertilization
10. Multi-Head Sperm
Sperm has multiple heads or tails
This could happen due to heavy exposure to chemicals, toxins or high prolactin in the blood.
11. Coiled Tail Sperm
Damages in tail
Sperm cannot swim well
Indicates the presence of bacteria
Could be due to heavy smoking
12. Stump Tail Sperm
Tails are short, leading to low motility or movement
Could be due to the late formation of sperm in the testicles
Is an autosomal genetic disease
13. Swollen Mid-Piece
The sperm neckpiece will be swollen
Indicates defective mitochondria
The guidance system to move the chromosomes from the sperm's neck might be broken or missing.
How to Improve Sperm Morphology?
When you have low sperm morphology, you want to know how to increase sperm morphology. Here are a few tips to improve sperm morphology:
Wear loose-fitting underwear
Avoid self-medication
Avoid steroids, tobacco, and alcohol
Avoid hot tubs or constant exposure of the testicles to heat
Exercise regularly and follow a healthy diet rich in antioxidants
If overweight, then lose weight with guidance
Can Abnormal Sperm Morphology Cause Birth Defects?
Unless the sperm head is carrying defective genes or broken DNA, the sperm morphology won’t cause any birth defects. Birth defects are mostly due to damage in the DNA package and it can be from either partner. Abnormal sperm morphology will make it difficult to conceive but may not cause any defects in the baby.
FAQs
How to Correct Sperm Morphology?
Simple changes to lifestyle and diet can have a big impact on your sperm health and morphology. In case of abnormal sperm morphology, a fertility specialist can help identify the exact problem and help rectify it.
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