When discussing pregnancy, we often tend to focus solely on the woman. However, the male factor is equally relevant, and in many cases, sperm quality can become a barrier to achieving natural conception.
Unhealthy lifestyle habits, prolonged stress, tobacco or alcohol consumption, and even environmental factors can impair the fertilizing capacity of spermatozoa. In severe cases, this may lead to male infertility (World Health Organization, 2021).
In these scenarios, embryologists play a key role: they are responsible for selecting and optimizing sperm with the best morphology and motility, thereby increasing the chances of success in assisted reproduction treatments.
What Is Sperm Capacitation?
Sperm capacitation is a laboratory procedure aimed at isolating sperm cells with the highest potential to fertilize the oocyte. In a way, this process mimics the natural selection that takes place in the female reproductive tract, where only the most competent sperm reach the egg (World Health Organization, 2021).
Through different techniques, it is possible to recover sperm with good motility and morphology, even when the male factor poses a limitation in treatment.
Main Techniques for Sperm quality Optimization
Density Gradient Centrifugation
This method uses two solutions of different densities. When the semen sample is centrifuged over them, the most competent sperm—those with superior motility and morphology—are able to pass through the layers and concentrate at the bottom of the tube. This mechanism partially replicates the natural journey of sperm in the female reproductive tract (Esteves et al., 2021).
Swim-Up Technique
The swim-up method selects sperm based on their ability to “swim” in a culture medium. After centrifuging the sample and adding the medium, it is incubated at body temperature for 30 to 60 minutes. Motile sperm migrate to the upper fraction, while immotile ones remain at the bottom.
Numerous studies have demonstrated that both density gradient centrifugation and swim-up techniques allow the recovery of sperm with characteristics similar to those found in fertile men, thereby increasing the likelihood of achieving a successful pregnancy (Esteves et al., 2021).
Sample Evaluation: The REM
After sperm capacitation, it is essential to count and analyze the recovered sperm. The most commonly used parameter is the REM (motile sperm count), which measures how many progressively motile sperm are present per milliliter (World Health Organization, 2021).
Based on the results, a specific treatment is recommended:
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REM > 3 million/ml → intrauterine insemination (IUI).
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REM between 1 and 3 million/ml → conventional in vitro fertilization (IVF).
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REM < 1 million/ml → intracytoplasmic sperm injection (ICSI).
In cases of low sperm quality, some centers apply advanced selection strategies, such as triple sperm selection, which combine different methods to further optimize outcomes.
Conclusion – SPERM quality
Sperm quality is a determining factor in male fertility, but biomedicine offers effective solutions to overcome these challenges. In addition to laboratory techniques, men are encouraged to adopt healthy habits: balanced nutrition, adequate rest, regular exercise, and stress reduction. All of these contribute to improving fertility naturally (World Health Organization, 2021).
Ultimately, the joint effort between specialists and patients enhances the chances of fulfilling such a significant aspiration: building a family.
References
Esteves, S. C., Sánchez-Martín, F., Sánchez-Martín, P., Schneider, D. T., & Gosálvez, J. (2021). Comparison of reproductive outcomes in oligozoospermic men undergoing intracytoplasmic sperm injection with ejaculated spermatozoa recovered after density gradient centrifugation or swim-up preparation. Andrologia, 53(1), e13897. https://doi.org/10.1111/and.13897
World Health Organization. (2021). WHO laboratory manual for the examination and processing of human semen (6th ed.). Geneva: WHO Press.
