The drug is already known to affect spermatozoid movement, causing them to swim in circles, and alters the gametes’ shape and size, but a study published in December details how that happened
Some studies have demonstrated that the consumption of marijuana by men affects the movement of spermatozoids, causing them to swim in circles, as well as altering the format and size of the gametes. Now, a study published in December last year in the journal Epigenetics has shown how that happens. Results are point out the reproductive risks associated with the use of that drug.
After evaluations, 24 men between the ages of 18 and 40 concluded the study, 12 of them marijuana users and 12 not. After the analyses, it has been identified that the cannabis active principle, tetrahydrocannabinol (THC) causes changes in the spermatozoid DNA. Besides, the use of the drug has been associated with a significantly smaller concentration of spermatozoids, compared to that among non-users.
Marijuana and male fertility
Paulo Gallo, an expert in human reproduction and medical director of Vida – Centro de Fertilidade, explains that the spermatozoid carries the male DNA which will form the embryo. During the formation process of the gamete, any substance in the blood will affect this material.
According to the study, the interference happens during the DNA’s methylation, which is its maturing process. When it is altered, there is a fragmentation of the molecules. “With more fragmented molecules, there is a smaller possibility of fertilizing an egg. When a man uses marijuana, these substances are absorbed and go straight into the bloodstream. Through the blood, the THC reaches the cells that produce spermatozoids,” says the expert.
The study, however, has some limitations. One of them is that the sample is small, which prevents generalizations. Another one is that there is a series of potential factors that may affect DNA methylation, which have not been considered by the study, such as lifestyle, physical condition, diet, sleep quality, and alcohol consumption.
Regarding the concentration, the doctor explains that, in normal conditions, the ideal is 15 million spermatozoids per milliliter, and 30 percent of them should have a good morphology and 32 percent a good motility, which is its ability to move and have a sense of direction. Since the DNA of the gametes is affected, these characteristics may be lost. Another problem which can be caused by the use of marijuana is erectile dysfunction, commonly known as sexual impotence.
The compromise of fertility is relative. Some men may have naturally bigger concentrations of spermatozoids, whose production is continuous. “It takes 72 days to form a spermatozoid. In men with an optimal production, even if they smoke [marijuana], there won’t be any problems,” says Gallo.
The opposite is also true. “Men with a slightly deficient production, but with a limit inferior to the normal figures, have a bigger chance of becoming infertile if they use marijuana,” says the expert. If the man wants to have children, the ideal, according to Gallo, would be to refrain from consuming the drug from three to six months. “Usually this scenario can be reverted, although not always.”
The international study points out that it is still uncertain if changes in DNA methylation are capable of being passed along from a man to his sons. Gallo says that “perhaps” the process can cause genetic mutations which are transmitted to the next generation.
Other studies have indicated little association between the use of marijuana by men and women and fecundity rates. Most of them, however, indicate negative issues. A research done by US universities has shown that the average conception time was significantly smaller among women who used marijuana regularly compared to those who never used the drug.
Added to that is the fact that marijuana reduces libido and that, as consumption accumulates throughout the years, the consequences may be aggravated. Even occasional users may have their fertility reduces due to abnormal ovulation.
READ IT IN PORTUGUESE:
Já se sabe que a droga afeta a movimentação dos espermatozoides, fazendo-os nadar em círculos, altera formato e tamanho dos gametas, mas estudo publicado em dezembro detalha como isso ocorre