Unprecedented research analyzed samples collected over 27 years at Caism
Master's research from the Faculty of Medical Sciences (FCM), carried out with 9.495 men treated at Unicamp with complaints of not getting their wives pregnant, concluded that there has been a decline in semen quality over the last 27 years in the Campinas region. “If these numbers continue to fall, couples may find it more difficult to achieve a pregnancy,” concluded biologist Anne Ropelle, author of the dissertation.
This research is the first in Brazil to have a large sample and a long follow-up period – from 1989 to 2016. 18.902 semen samples were produced at the Hospital da Mulher Prof. Dr. JA Pinotti - Caism.
The collection was evaluated based on three seminal standards: concentration (quantity of sperm in the sample), progressive motility (sperm movement capacity, important for meeting the egg and fertilization) and morphology (sperm shape).
“The parameters studied have worsened over the years, however, the average sperm concentration and percentage of sperm with progressive motility are still normal according to the parameters of the World Health Organization (WHO)”, informed gynecologist Luiz Francisco Baccaro, professor from FCM and study advisor.
According to him, an average sperm concentration equal to or greater than 15 million per ml and a seminal volume greater than 1,5 ml are considered normal. Men who have values below these limits may have greater difficulty getting their partners pregnant.
The average sperm concentration between 1989 and 1995 was 86 million per ml. From 2011-2016, it fell to 48 million, but is still within normal limits and above 15 million.
The same was true for progressive motility. The WHO considers a value equal to or greater than 32% to be normal. Between 1989 and 1995, the average was 47%. Between 2011 and 2016, it fell to 36%.
In terms of normal morphology, the value was 12% between 1996 and 2000. Now, it is 3,7%, a value slightly below what would be normal according to the WHO (greater than 4%).
Even though the objective was not to unravel the reasons for the decline, the advisor and student realized that the way forward was to probe more deeply into the already known factors – such as obesity – that can lead to infertility.
“In the study, we only had variables in the database such as the year the sperm was collected, the man's age and variables such as sperm volume, color and pH”, said Baccaro. “It would also be interesting to know, in a future study, whether these men smoked, drank or used drugs, in addition to sociodemographic variables and personal habits.”
An alternative for couples who want to get pregnant is assisted reproduction, a set of techniques to facilitate pregnancy. Today, to be admitted to Unicamp's Human Reproduction Outpatient Clinic, the couple must have tried to get pregnant for at least a year, without success. One of the tests for diagnosing infertility is the spermogram, which assesses whether men have changes that could influence fertility rates.
Mismatch
According to Baccaro, the decline in the quality of human semen has been the subject of investigation in recent years. Since 1992, publications on the subject suggest that there has been a decline in the seminal quality of men around the world since the mid-20th century.
However, this fact is not unanimous. Some articles question the scientific methodology used in other articles that report a drop in seminal quality. Since the publication of articles suggesting a worsening of sperm parameters, much has been said about the involvement of endocrine disrupting agents, substances that would act on the male fetus, modifying the development of the testicles.
These agents would have the potential to mimic, block or modulate the endocrine response by interacting with steroid hormone receptors (such as chemical agents and pesticides), leading to testicular dysfunction.
Baccaro believes that the cause of infertility may be related to the obesity epidemic in the world. Obese men show an imbalance between the hormones estrogen and testosterone, because peripheral fat increases estrogen concentration and decreases semen quality.
“Obese people have a lower concentration of sperm in their semen [semen is the result of a mixture of secretions and sperm”, explained Baccaro. “We don’t know if this happened to our population, but this reason would make more sense to investigate.”
There is a consensus that exposure to smoking and low childhood growth standards are combined with increased fat in adolescence, alcoholism and drug use in adulthood as risk factors for low sperm production.
History
Anne's study is one of the few to analyze men retrospectively in the country, where there is little work on the subject. They have a smaller number of samples and the time period is shorter compared to the Caism study.
To evaluate the semen, two samples were collected and analyzed from each man. They should come to the hospital with sexual abstinence for three to five days, collect the sample on the day of the appointment and 15 days later.
The oldest samples were obtained from the Human Reproduction Laboratory, which has been performing routine spermograms at the hospital since 1989. This information is all processed in a database.
A strong point of the analysis is that it was carried out in a single laboratory, reducing the possibility that the results obtained would be influenced by variations in examination technique.
Recent studies suggest that, like women who have lower quality and quantity of eggs after the age of 35, the quality of a man's semen may also reduce after the age of 40. “When we analyzed the database, we observed that the average age of men treated at the Caism Infertility Outpatient Clinic has increased”, commented the doctor.
On the other hand, in the multiple analysis, Baccaro and Anne noticed that the year of semen collection had an influence on the result. Therefore, an individual who collected sperm in 2015 had a lower concentration of sperm, less mobile sperm and sperm with more atypical morphology than the man who collected it in 1989.
Demand
The search for specialized services in human reproduction is more frequent today because couples have postponed pregnancy, considering new studies and opting to seek professional stability first. And they postpone the plan of having a child, especially in the higher classes. In the lower classes, pregnancy in general can still occur earlier, although this situation is already beginning to change.
Previously, it was thought that specialized services in human reproduction would be available exclusively to people from higher social classes. But at the moment, in Anne's opinion, access to qualified information has increased and there has been greater awareness that Unicamp's infertility service serves patients through the SUS and that, therefore, it can be sought by everyone.
Another aspect that contributed to this is that the WHO considers infertility a disease. Therefore, the infertile couple has the right to resolve this problem, just like a couple who does not want pregnancy. The Women's Hospital offers 100% SUS care and is a reference in the area.
“A couple who cannot get pregnant unfortunately becomes stigmatized in society. Studies show that the chances of a divorce increase”, said Baccaro. “However, with advances in medicine, we are seeking to find a solution to this dilemma and investing in new research.”
Controlling weight, practicing physical exercise, not overindulging in alcohol consumption, drug use and smoking are some relevant conditions for improving semen quality, guaranteed the advisor.
For years, it was thought that infertility was due to the woman, since she is the one who gets pregnant. It is estimated today that 40% of infertility is due to female causes, 40% to male causes and 20% to both. It already affects 15% of the world's population, and it is estimated that in Brazil alone there are more than 200 couples who have difficulty having children.
