Age is a very important factor when it comes to conceiving, especially the age of the woman. There are several factors by which maternal age has a great influence on female fertility. The following are the different factors:
First, there are the oocyte and embryonic factors. The age of the woman has a strong relationship with the number of eggs available and their quality. As is well known, women begin to produce the eggs that will accompany them throughout their lives when they are still developing in the womb. At the moment of birth they already have a limited number of eggs and, starting with the first menstrual period, a process of "selection" of the best eggs begins in each menstrual cycle. This means that, as the years go by, women will have fewer and fewer eggs, and these will be of poorer quality.
With regard to egg quality, it should be noted that, with age, the percentage of aneuploidy (alterations in the number of chromosomes) increases exponentially. To make sure that the embryo to be transferred does not have aneuploidies, it is recommended that a genetic study of the embryos, the so-called PGT-A, be carried out beforehand.
Secondly, there are the endometrial factors. The uterus and the endometrium (internal lining of the uterus that allows pregnancy to develop) age just like other tissues. This results in the appearance of fibrous connective tissue, which alters the natural properties of these organs. Thus, the uterus becomes less elastic, the number of blood vessels that nourish the embryo is reduced, scars or alterations appear (such as fibroids and polyps) that prevent the embryo from developing, etc.
Also, with age, our immune system loses some of its capacities, which can affect fertility. It is now known that the process for an embryo to develop in the womb involves a response by the woman's immune system. It can happen that the immune system does not allow the embryo to be accepted by the uterus and that, as a result, repeated implantation failures or repeated miscarriages occur.
Finally, it must be understood that the aging of the woman in itself also represents a challenge to fertility.
The general state of health of the pregnant woman also compromises her chances of achieving a successful pregnancy. In other words, it is not the same for a 30-year-old woman with no previous illness to face pregnancy as it is for a woman of an older age and, possibly, with less favorable health conditions.