Egg donation is the Assisted Reproduction treatment with which better pregnancy rates are achieved, and may be higher than 90% after two attempts. However, an egg donation does not ensure pregnancy. We will then try to explain why this treatment does not always work.
What is ovodonation?
Ovodonation is an in vitro fertilization (IVF) treatment in which we use oocytes from a healthy and young donor to generate the embryos that we will later transfer to the inside of the recipient woman's uterus. It is indicated in cases in which the patient can not or is not recommended to use her own eggs (absence of ovaries, low ovarian reserve, poor oocyte quality, genetic alterations, absence of pregnancy after several cycles of IVF).
Egg donors are young women (under the age of 35) and healthy. This makes their eggs have a high quality and, therefore, the embryos that are generated from them a high probability of producing pregnancy. However, while the oocyte is a crucial factor in determining the success of an Assisted Reproduction treatment, it is not all. There are other factors that determine the implantation capacity of an embryo and that conditions that pregnancy occurs or not.
Factors that affect the success of ovodonation
The age of the male influences the quality of spermatozoa. In most couples who perform egg donation treatment the male is over 44 years old and this translates into a poorer quality of their gametes with a higher index of chromosomal abnormalities in them.
On the other hand, there are other alterations in spermatozoa that can not be diagnosed in a normal seminogram and, however, can significantly condition the probability of pregnancy.
The fragmentation of sperm DNA is an indicator of the degree of oxidative DNA damage of spermatozoa. When the fragmentation is high (> 30%), the probability of pregnancy may be less than 2%. In URH García del Real we systematically study sperm DNA fragmentation for all couples who are going to make an egg donation treatment, and if it comes out high, we have different strategies to reduce it and increase the probability of pregnancy.
The effect of the masculine factor on the embryonic quality is mainly between the 4th and 5th day of embryonic development. For this reason, embryonic long culture up to blastocyst stage will give us a lot of information about the possible presence of a male factor, and will help us to select embryos with greater implantation potential.
In URH García del Real, in all cycles of egg donation we make the embryo transfer in stage of blastocyst .
For an embryo to be implanted a good dialogue between the embryo and the endometrium. We still have a lot to learn about embryo implantation, but we know that there are certain things that can hamper the implantation capacity of an embryo.
Thickness and appearance of the endometrium is critical for implantation. In most cases the treatment with estrogen and progesterone allows us to get an adequate endometrium. However, in other cases it is not so easy and we need to combine different therapeutic strategies to achieve it. If we do not get an optimal endometrium it is preferable to freeze the embryos and delay the embryo transfer.
Endometrial polyps, the presence of submucosal or intramural myomas that distort the uterine cavity, septa or septa in the uterus, make it difficult to correctly implant the embryo. In URH García del Real before a cycle of egg donation we always make an exhaustive study of the uterus to rule out this type of alterations.
Infective or inflammatory pathology of the endometrium (endometritis) can also decrease the probability of pregnancy. Endometritis is a pathology that, in most cases, may go unnoticed. For this reason, it is important to take an endometrial biopsy in patients who have not been able to achieve pregnancy following an egg donation cycle to rule out an alteration of this type and, if it exists, to treat it.
Other aspects such as the genetic expression of the endometrium during the implantation window or the role of the endometrial microbiota in implantation are under study. More scientific evidence is still needed to arrive at solid conclusions in this area.
Systemic alterations in implantation failure
- Coagulation disorders (thrombophilias): although there has been a very important role for coagulation disorders in patients with implantation failure (who have not achieved pregnancy after successful transfers of good quality embryos) for a long time, Today, much is being questioned whether thrombophilias are responsible for implantation failure.
- Immunological alterations: the immunology of reproduction is also under study. Multiple treatments have been postulated to correct possible immunological disorders and their impact on implantation, however, we still lack sufficient scientific evidence to be able to recommend these treatments.
Lifestyle to promote pregnancy
There are multiple factors of our day to day that will condition the probability of pregnancy. Overweight, tobacco, alcohol consumption, decrease the likelihood of pregnancy and increase the risk of miscarriage. Maintaining a healthy lifestyle, playing sports, following a balanced diet and eliminating tobacco and alcohol consumption is critical to good health and increased likelihood of pregnancy.