Understanding Sperm Motility: Quality, Impact on Fertility, and Treatment Options
- When receiving IVF treatment, MOT5 or lower is sufficient
- When receiving IUI treatment, MOT10 or higher is recommended.
One of the most significant factors in male fertility is sperm motility – the ability of sperm to move adequately. High sperm motility is crucial for natural conception, as it influences the sperm's ability to swim through the cervix, uterus, and fallopian tubes to fertilise an egg. Understanding sperm motility, the quality required, and potential treatment options can enhance one's conception journey.
What is Sperm Motility?
Sperm motility refers to the sperm's ability to move in a forward direction. The motility of sperm is commonly classified into two categories:
Progressive motility: Sperm cells that swim in a straight line or large circles.
Non-progressive motility: Sperm cells that swim but not in a straight line, for example, in small, tight circles.
A semen analysis typically checks the percentage of sperm exhibiting progressive motility. A healthy sperm count typically shows more than 40% of sperm exhibiting progressive motility.
Importance of Sperm Motility in Fertility
High sperm motility increases the likelihood of successful fertilization. Sperm must traverse the female reproductive system's challenging environment, swimming through the cervix, uterus, and into the fallopian tube to reach the ovum.
A sperm's movement is largely influenced by its structure, particularly the tail. The tail propels the sperm and enables it to travel the necessary distance to the egg. Consequently, any abnormality in the sperm's structure can hinder its journey, leading to reduced fertility.
What are normal levels of sperm quality?
A crucial part of assessing sperm quality is the evaluation of semen parameters, such as sperm count, motility, and morphology.
Sperm Count: Also known as sperm concentration. This measures the number of sperm present in a millilitre of semen. According to the World Health Organization (WHO), a normal sperm count consists of 15 million sperm per millilitre or more. A healthy result shows at least 40% of the sperm exhibiting progressive motility.
Factors Affecting Sperm Motility
Multiple factors can affect sperm motility, including lifestyle choices, environmental influences, and medical conditions:
- Lifestyle factors: Smoking, alcohol consumption, drug use, stress, and obesity can negatively impact sperm health, including motility.
- Environmental factors: Prolonged exposure to heat, radiation, heavy metals, and toxins can impair sperm motility.
- Medical conditions: Varicocele (swelling of the veins that drain the testicle), infections, hormone imbalances, and certain medications can affect sperm motility.
Assisted Reproductive Technologies (ARTs)
When natural conception is challenging due to low sperm motility, assisted reproductive technologies offer alternative paths to parenthood:
- Intrauterine Insemination (IUI): In this process, sperm are washed, concentrated, and then directly inserted into the woman's uterus, bypassing the cervix to give them a head start in their journey.
- In Vitro Fertilization (IVF): IVF involves fertilizing an egg with sperm in a lab.
- Intracytoplasmic Sperm Injection (ICSI): When low sperm motility is a concern, a technique known as Intracytoplasmic Sperm Injection (ICSI) can be used. The process involves injecting a single sperm directly into an egg to achieve fertilization.
Success Rates of IUI and IVF
Intrauterine insemination (IUI) and In Vitro Fertilization (IVF) are two commonly used assisted reproductive technologies (ARTs) that can aid couples facing fertility issues.
IUI Success Rates: IUI success rates can vary based on factors like age, fertility diagnosis, and whether fertility drugs were used. According to the American Pregnancy Association, the success rate of IUI ranges from 10-20% per cycle for women under 35. Success rates tend to decrease as women age, mainly due to the natural decline in egg quality and quantity.
IVF Success Rates: IVF tends to have higher success rates than IUI, primarily because it involves more direct intervention in the fertilization process. According to data from the Centers for Disease Control and Prevention (CDC), the success rates for IVF can range from 21-54%, again largely depending on the age of the woman.
Intracytoplasmic Sperm Injection (ICSI), often used in conjunction with IVF when there are severe male-related infertility issues, has a fertilization rate of approximately 50-80% per egg injected.
Remember, individual success rates can vary widely, and it's important to have a thorough discussion with your fertility specialist to understand your unique circumstances and potential outcomes.
What sperm quality should I choose?
MOT is short for 'Motility' – a term commonly used in the sperm donation industry to denote the concentration of motile (or mobile) sperm cells in a given sample. The numbers 5, 10, 20, etc., following the term MOT, refer to the millions of motile sperm cells per millilitre in a semen sample after it has been thawed. For instance:
- MOT5: This means that the sample contains 5 million motile sperm cells per millilitre.
- MOT10: This means that the sample contains 10 million motile sperm cells per millilitre.
- MOT20: This means that the sample contains 20 million motile sperm cells per millilitre.
When it comes to choosing the right quality, it generally depends on the type of fertility treatment being undertaken:
Intrauterine Insemination (IUI): A higher MOT number, such as MOT20, is usually recommended for IUI. This is because the sperm needs to be able to travel up through the cervix and into the fallopian tubes to reach the egg. The more motile the sperm, the higher the chances of successful fertilization.
In Vitro Fertilization (IVF): For IVF, especially when combined with Intracytoplasmic Sperm Injection (ICSI), a lower MOT number, like MOT5, is often sufficient. This is because the sperm is directly introduced to the egg in a laboratory setting, minimizing the need for a large number of motile sperm.
