We all have the feeling that there are a lot of people who have a birthday around the same time as us. This may lead us to think that we were born at a time when birth rates are higher than usual, but this is usually just a confirmation bias. Now there really is most fertile season? This is a question that many scientists have asked themselves, and while there are serious doubts about the causes, some research seems to point to the fact that there is a season in which they occur. more pregnancies.
In fact, it has been studied in both Assisted reproduction how in natural concepts. Regarding the former, a review of studies has recently been published indicating that in cycles fertilization in vitro if ovules frozen in summer are used. On the other hand, with regard to natural conception, the most fertile season varies in different parts of the world, which confirms that in some sense it could be something more than a coincidence.
But the reasons are not clear. Scientists who believe that a more fertile season does exist believe that this may be due to factors such as temperature or daylight. There are also researchers who believe that certain changes in a person’s habits can affect the possibility of pregnancy. In short, nothing definite, just some hypotheses. They are the most accepted so far.
What about frozen eggs?
When does the fertilization cycle occur? in vitro, suppositories are not always used immediately. There may be times when someone keep your suppositories for use over time. Thus, even if you are older, you will use gametes from when you were younger and therefore less damaged.
They may also be donor eggs. In this case, they freeze until they find someone who needs to use them.
In these and other situations related to freezing or vitrifying eggsit seems that the time at which it is done is important. At least, this is the conclusion of a recently published review in human reproduction. It analyzes previous research, concluding that summer appears to be the best time of year to collect eggs.
The first of these studies analyzes 3657 embryo transfers for eight years at a fertility clinic in Perth. Australia. It can be seen that embryos obtained with ovules collected on days with more than 10 hours of sunshine They had 28% more likely to result in a live birth than those collected with less than 7 hours of sun per day. On the other hand, there seemed to be no connection with temperatures.
On the contrary, they seem to influence the second study analyzed. In this case, they change hemispheres and go north, namely to an American city Boston. There, in 2022, it was observed that oocytes collected in summer they had 42% more likely finish with delivery on time, compared to those assembled in winter. In addition, those collected on warmer days had 34% more likely lead to a live birth.
It is important to note that all this applies only to the moment of collecting the eggs. If they were frozen and fertilized later, it doesn’t matter. From the time of transfer to the uterus.
Reasons are unclear
It is not clear to the authors of this review of studies why. It seems safe to conclude that summer is the most fertile season of the year, at least in terms of egg retrieval. However, it is not known whether by number of hours of sunshine or by temperature. If it was the first, then it could be related to melatonin or vitamin D.
Melatonin is a hormone closely related to circadian rhythms. Its release is suppressed during the day and stimulated at night, signaling it’s time for sleep. It may be that the more hours inhibited, the higher the quality of the eggs. But this is not clear. As for vitamin D, solar radiation stimulates its synthesis, so it can affect the quality of oocytes. But this is unknown. What about natural reproduction?
Most fertile season in natural pregnancy
In addition to assisted reproduction, there was also talk of a possible most fertile season. Although there are many doubts about this. For example, it was noticed that Europe there is a peak birth rate March and April, while in the southern United States, birth rates decline around April and May. Than it can be caused?
There are many hypotheses about this. First, it may be a matter of temperature. It is known that sperm quality decreases with high temperatures. Especially when using very tight clothing, which further raises the temperature of the testicles.
Considering that the temperature in the southern United States is very high in summer, it may be that nine months later, in April and May, there will be fewer births. In fact, there are studies that suggest that high temperatures can also lead to the death of embryos in the very early stages of pregnancy. Even before the discovery of pregnancy.
On the other hand, there are studies indicating that during the holidays like christmas or summerpeople are more likely to have unprotected sex. This is what leads to so many spring births in Europe. But also in September. Other studies in Iran have identified a peak birth rate in autumn.
Finally, there are studies pointing to the importance photoperiod. In other words, as with eggs in assisted reproduction, it is believed that there may be a more fertile season depending on the number of hours of sunshine per day. None of this is known for certain. After all, babies are born all year round. But it seems true that depending on where we live, the heat, the amount of sunshine, and even how we dress or our habits, there may be a more fertile season. Most studies point to summer. So if you’re looking for offspring and live in the northern hemisphere, this might be the best time to get started.
Source: Hiper Textual
