Semen parameters may vary with the seasons, a report from Italy.
A curious retrospective study has been published in Italy highlighting the seasonal variation of human semen parameters. As you have read in this blog and also in medical literature, the issue found in over half of couples that consult at a fertility clinic is that of male infertility.
The researchers of this study gathered data from 5,188 men at the Centre for Reproductive Incapacity of the University Hospital of Parma, in northern Italy, with the goal of determining whether the seasons affect the functional patterns (pH, volume, sperm motility and number of sperm) in semen samples. Dr. Alfredo De Giorgi led this study, which was published in the journal, Chronobiology International.
Several fascinating data proceeded from this study. Interestingly enough, higher sperm motility was found in summer time. Normal sperm pH was higher during the spring. The volume of sperm was the highest in winter.
So what conclusions can we draw from this report? To begin with, we should note that this is just one study carried out in one country. Therefore it is no basis to confirm that this is a consistent worldwide phenomenon. What is interesting, however, is that these researchers have seen that sperm is more active during the summer months. Motility is a key factor in achieving pregnancy because the sperm has to swim through the cervix, uterus, and fallopian tubes in order to reach the egg. In winter, on the other hand, the sperm appeared to be less active. The researchers found that sperm motility over 40%, the normal value, drops from 65.3% in summer to 50% in winter. They felt that this could be due to changes in the men’s hormone levels. Although not examined in this particular study, they hypothesize that testosterone may play a large role in this fluctuation.
This could mean that July and August are the most likely months for conception to take place. It is interesting to take a look at exogenous influences on sperm production. It brings to light that there are many things that we cannot control with the sperm in an IVF cycle. The same could be the case for women. Outside factors might be an explanation when sometimes it is just not understandable why a woman does not get pregnant after a cycle has gone so well. There are certainly exogenous factors that substantially impact human reproduction, and this is an interesting field for further study in the future.