Historically, it is the responsibility human fertilization She always fell to women. By postponing maternity and increasing complications to achieve reproductive research pregnancies, they focused their efforts on the female factor.
Nevertheless, science of fertility in recent years has begun to look seriously at the man. Especially for his seed. The latest scientific review published at the end of 2017 in the journal Updating human playback confirms that the seed of Western men Now it's worse than 40 years ago.
sperm concentration with an average of 99 million sperm per milliliter in 1973 to 47.1 in 2011, down 52.4%. But the decline is even more pronounced in the second variable. Of the 337.3 million sperm ejaculated in the seventies of the last century, it reached the current 137.5 million, 59% less.
From 1970 to present, the quality of sperm of men fell by 2% each year
Concerning the specific case Spain has a bit of a study, but it all suggests that this decline is happening. In 2008, research has been published in more than 60 centers of assisted reproduction of all autonomous communities that have confirmed the great geographic inequality in terms of quality seeds which exists in the country.
While in Galicia, only 8.5% of young people have a sperm concentration lower than the World Health Organization (WHO) values, while in Andalusia, Madrid and Basque the number increases to 13.7%. %, 14.8% and 18.7% respectively; and reach 22.7% in Catalonia and the Valencian community.
It remains to know how these data will affect the future of our reproductive capacity. Although at this point the rate drops natural conception which can be expected with regard to the reduction in sperm count, are beginning to jump warning about the evolution of male fertility.
More and more children are born after fertility treatment, but despite the increased use of assisted reproduction, the fertility rate in many countries – such as Spain – is still significantly below replacement rate (2.1 children per woman).
40% of the cause is unknown
Today is the only acceptable tool for assessing male fertility basic semen or sperm analysis, which is not entirely useful given its limited specificity and sensitivity, and does not allow it to be determined with certainty whether the individual is fertile or not.
International Study on Causes of Men's Infertility, published at the end of 2017, in collaboration with a researcher at the University of Murcia Jaime Mendiola, concludes that 15% of men are currently infertile.
Among them is 40% of cases unknown causes; 15% is due to a genetic disorder associated with the fertility problem; and 30% are patients with genetically modified semenograms.
"On the one hand there are simultaneous exposure (nutrition, lifestyle, endocrine disruptors), but there are also works that show intrauterine or prenatal exposure (such as anogenital distance predicting changes in reproductive function during adult life)", says Sinc Mendiola.
"10 or 15 years ago, the man had no" guilt "if the woman did not get pregnant, and that changed. We lost the seed quality at a rate of 2% per annum from 1970 to 2010 – The Spanish scientist continues. Occasional control of human reproductive health would reveal changes that, if not treated in time, become irreversible. "
Today, the only acceptable tool for assessing male fertility is the basic analysis of semen or sperm but is not fully useful
In the same line, the investigation was published in October 2018 9% increase in men's risk of need for fertility treatments parents (from 12.4% in 2004 to 21.3% in 2017). The sample, which has formed about 120,000 Spanish and American individuals, has been the largest ever used in world scientific literature.
"On the one hand, this confirms the drop in quality of semen in infertile men as it is in the general population," explains Sinc. Nicolás Garrido, Director of the IVI Foundation and co-author of the study. "And on the other hand, this fall has clinical repercussions with apparent effects on male fertility: As quality is more affected, more complex assisted reproduction techniques are needed compared to one or two decades ago.
Can sperm quality be improved?
Reproductive task is the luxurious function of the human body. "If any organism has a type of problem, it's the first thing it releases. From that point of view, any behavior in favor of our overall health can contribute to improving sperm quality," adds Garrido.
However, sperm quality can not be returned to the laboratory, ie no treatment in vitro which improve sperm. What can be done, within the available human sample, is to select those that represent the optimal characteristics when it comes to achieving reproductive success.
However, numerous studies have analyzed several factors that could improve this quality, although the existing literature contrasts. One of the most important is exercise.
"The level of desirable ideal physical activity and its impact from a therapeutic point of view does not mean improving seed quality," said Fernando Quintana, director of the AndroLoc Laboratory IVI Bilbao.
The sperm quality can not be detected in the laboratory, there is no treatment in vitro which have better sperm
The second element is antioxidantsAccording to Mendioli, "normal." When a man goes to a clinic for assisted reproduction, he gets an antioxidant. But if we look at the scientific literature, there are at most ten well-crafted works that talk about it. Sometimes it is prescribed by looking for the placebo effect. More studies would be needed to determine if the provision of this supplementation is adequate.
Considering snuff and its linkage to sperm mobility has more research. Seed quality is also negatively associated with stress, as well as the constant situation as accurate. Even with taking red meatas in one of the last works of Jaime Mendiola.
The age of man is important, but less
Equally controversial is the impact male age in sterility. "Although numerous endocrinological, testicular, morphological, functional and genetic changes have been described in sperm, their causative role in sterility is disputed," Quintana said.
In a study that analyzed 46,078 first treatments fertilization With donor sperm and in vitro fertilization cycles (IVF) and intracytoplasmic sperm injection (ICSI), it was found that the number of live births and spontaneous abortions in reproductive treatment was not affected by the age of the donor until 45 years
"When a couple comes to the breeding center, they do a thousand tests," says Sinc. Miguel Ruiz Jorro, Clinical and Vocal and of the Spanish Society of Fertility (SEF). "But not that the seeds are forgotten or there is little research about it." The problem is that a specialist in reproductive medicine sometimes does not consider it and continues to look for the same thing as 50 years ago: semengram.
For Ruiz Jorra, from the first moment you have to include men. "It is very important to know the causes behind it, because it can affect the health of a man, his future children, and the probability of pregnancy." In addition, a low number of sperm may be associated with a disease such as testicular cancer. "
"When a couple comes to the breeding center, they work a thousand tests for him, just like 50 years ago: a seminogram," says Miguel Ruiz Jorro
Freeze the egg cells yes, no sperm
With the genetic information we have today, we discard larger chromosomal risk for children of older parents. "But 45-50 years should be taken into account if, if DNA is fragmented, it may be related to other diseases," Ruiz Jorro continues.
However, the possibility of freezing seeds for non-medical reasons has not been made. According to Nicolás Garrido, "this is not a practical option. First, because they are used in health are not so much, and secondly, because you make sure you have to go through the treatment of reproduction."
While men make sperm every day, production ovaries and their quality drastically decline after a certain age. Therefore, in this case, freezing has positive clinical effects due to increased risk of genetic problems in the future child. For now, the goal of assisted reproduction is still more focused on women.