First male fertility study in the Barcelona area
Semen from local men from the Barcelona area is amongst the worst in the world:
- Semen quality increases with ejaculations.
- Tobacco and drugs do not cause, apparently, a worsening of the semen quality
- Stress reduces the number of spermatozoa.
- The influence of lifestyle habits traditionally associated to infertility is at stake.
Only 34, 4% of the men in Barcelona have a semen that can be considered “normal”, according to the parameters established by the WHO. This is what states a semen quality study carried out by Institut Marquès in Barcelona, which shows that 65, 5% of the males in this province do not comply with the criteria of normality of the WHO, regarding number or motility of their spermatozoa. In the case of men from La Coruña, North West of Spain, a 59% shows normal semen, according to WHO.
It is the most comprehensive study about semen quality carried out among the general population. It has been compiled over the past 12 months by members of the Infertility Service from Institut Marquès, under sponsorship of the Spanish Andrology Association, the Spanish Fertility Association and the Support Association for Fertility “Genera”.
The study was conducted from 1005 semen samples of males aged between 18 and 65 years. The study has allowed handling 105525 data, both medical and sociological. The objective was to analyse the semen characteristics of Spanish males from the areas of Barcelona and La Coruña, compare the results with those from other countries and try to establish the implication of lifestyle habits and the environment.
Main findings of the study
Only 34, 4% of the local men from Barcelona have a semen considered “normal” by WHO standards.
65, 6% of men do not meet the WHO normality criteria regarding number or motility of spermatozoa. This does not mean in any way that they are infertile, but we can talk about a kind of generalized “subfertility” in the analysed population. This could mean that it will take longer for their partners to get pregnant or that a growing percentage of males will require medical aid in order to have children.
We must keep in mind that within these figures we do not include those males who declared to be searching for a pregnancy, which were excluded from the sample in order to avoid a biased study. 17% of the males have oligozoospermia (low spermatozoa concentration, less than 20 million/ml, amount considered normal by the WHO). Astenozoospermia (low count of motile spermatozoa, less than 50%) was found in 62,3% of the males:
The male age did not significantly affect the classical parameters of the semen analysis: count, motility and morphology.
Males looking for a pregnancy ejaculate less
The sense of “task” supresses the male desire and women orient sexual intercourse almost exclusively to fertile days.
The more ejaculations, the better the quality of semen is
Semen quality is significantly better in males with a higher number of ejaculations and improves in direct proportion to a bigger frequency. It is a good stimulus for the creation of spermatozoa in the testicles, also known as “spermatogenesis”. The more, the better.
Testicular descent problems affect fertility
The most common testicular alteration found amongst the volunteers is the anomaly of testicular descent, also known as cryptorchidism (testicles do not descend into the scrotum), which accounts for 10, 1% of the volunteers and that entails a worse fertility.
A moderate alcohol consumption does not affect the semen quality, but an elevated consumption does harm it.
An elevated and usual alcohol consumption (over 3 drinks per day) reduces the concentration and motility on spermatozoa.
Stress reduces the amount of spermatozoa
Smokers do not have worse sperm than non-smokers do
Twenty-four percent of the respondents were smokers and a third from them acknowledged smoking more than 10 cigarettes per day. However, when evaluating the sperm analysis, smokers did not show any difference respect to non-smokers.
Nevertheless, aside from these results it should be noted that there are multiple scientific papers (Zitzmann and col.) that show that some substances contained in tobacco (such as benzopyrene, cotinine and pesticides used to fumigate tobacco leaves) reduce fertility.
Drugs consumption does not apparently entail worse sperm quality
12, 5% of the volunteers declared a usual drug consumption: 1% cocaine and, the rest of them, cannabis. This information is surprising and can be explained because these drugs induce the activation of the sperm function and spermatozoa, although ultimately they decrease their fertilizing capacity since spermatozoa, on their way to the egg, run out of energy and therefore its fertilization ability diminishes. On top of it, we have to take into account that this group presents a greater number of ejaculations, with an average per week of 4, 1, opposed to those who take no drugs at all and that ejaculation is an important stimulus for the formation of sperm.
Working in contact with toxics reduces the number of spermatozoa
An 8, 8% of the studied men reported to work in contact with toxic products or substances. Among the more frequent were organic solvents, phenols, dyes, insecticides, etc.
Average sperm analysis results and comparison according to WHO criteria
Working in contact with toxics reduces the number of spermatozoa.
|Results of the study in Barcelona||Normal values according to WHO|
|Ejaculate volume: 3,63 ml.||From 2 to 6 ml.|
|Concentration: 59,35 millions spermatozoa/ml||From 20 mill/ml onwards|
|Total amount of spermatozoa in ejaculate:
|From 40 mill/ml onwards|
|Percentage of motile spermatozoa: 41,72 %||From 50%|
|Percentage of type ‘a’ spermatozoa
(with fast, progressive and lineal motility): 14,45 %
|Percentage of spermatozoa with normal morphology: 13,89 %||From 14%|
Comparison with other Spanish provinces
|PROVINCE||Number of samples||Ejaculated Volume||Spermatozoa concentration
|Percentage of motile spermatozoa||Percentage of good motility spermatozoa||Total amount of spermatozoa with good ejaculate motility|
|LA CORUÑA||279||3,4 ml||91,7 mill/ml||53,20 %||28,70 %||89,4 mill|
|BARCELONA||1005||3,6 ml||59,3 mill/ml||41,70 %||14,40 %||31,1 mill|
|TARRAGONA||405||3,6 ml||65,9 mill/ml||40,20 %||6,80 %||16,1 mill|
|VALLÈS||105||3,5 ml||74,8 mill/ml||45,70 %||18,50 %||48,4 mill|
Geographic variations on semen quality in males with similar lifestyle habits (similar socioeconomic level, same race, etc.) could be due to differences on environmental, dietary and occupational exposure to toxic chemicals. More precisely, one of the possible causes for the decrease of male fertility could be the exposition to environmental chemical products, which act as “estrogenic disruptors”. This subject has not been widely researched yet, regarding its implications in human fertility. No doubt, this would mean a research effort capable enough to clarify and measure the consequences it has on human fertility.