In a high percentage of cases, couples with fertility problems achieve the desired pregnancy thanks to in vitro fertilization (IVF) treatments. However, when up to three good quality embryos have been transferred in patients under 37 years of age, or three biopsied embryos in patients over 37 years of age, and pregnancy is not achieved, then this indicates a problem of recurrent implantation failures, which may be related to genetic anomalies, uterine malformations, endocrine problems, thrombophilia, alterations in the immune system, and so on.
It should be taken into account that human reproduction is a delicate process involving numerous factors and elements that must work correctly for pregnancy to occur and be successful. Unfortunately, things do not always go as expected.
In general, these implantation failures are complicated moments that can cause the couple a great deal of anxiety and frustration. It doesn’t mean that pregnancy cannot be achieved, but it does imply that other options and assisted reproductive treatments to improve the process should be explored, focusing especially on improving the quality of the gametes.
HOW IS EMBRYO IMPLANTATION PERFORMED?
Embryo implantation is a biological process that allows an embryo to implant by attaching to the endometrium, the inner lining of the uterus. If all goes well, it will remain in place for the duration of the pregnancy, which, in normal circumstances, should be 9 months.
For the implantation to be successful, the embryo must be of good quality and develop optimally; the endometrium must thicken and mature; and there must be correct communication between the endometrial tissue and the embryo.
Implantation begins on day 6 of embryo development and ends on day 13. The so-called “window of implantation”, which is the moment when the process must begin, is between 2 and 7 days after ovulation.
WHAT ARE RECURRENT IMPLANTATION FAILURES?
Recurrent implantation failure is the term used when pregnancy is not achieved after several transfers with embryos that had been selected for their high quality.
In these cases, it’s necessary to perform a series of tests to determine the cause of the problem. This may be due to small anatomical abnormalities in the fallopian tubes or the uterine cavity that may not have been detected during the pre-treatment tests. It may also be caused by chromosomal abnormalities in the embryos, thyroid problems, celiac disease, poor coagulation, or abnormal functioning of the immune system, all of which prevent embryos from implanting.
WHAT FERTILITY OPTIONS ARE AVAILABLE IN CASES OF RECURRENT IMPLANTATION FAILURE?
In cases of recurrent implantation failure, it’s very important to perform an exhaustive study of the patient’s clinical history, ultrasounds and other analyses focused on determining the cause, such as a hysteroscopy, genetic and thrombophilia testing, thyroid examinations, or immune system tests.
In some cases, it may be necessary to resort to egg donation to obtain better quality eggs, which is recommended when the woman is of advanced age, or when her own eggs are of poor quality. However, the problem may also be due to the quality of the sperm, in which case the solution may be either to improve sperm selection or to use a donor.
However, it’s also advisable to take extra care of the embryos and transfer them at the blastocyst stage, which occurs around day 5 after fertilisation. This allows nature to “select” the embryos that are optimal and easier to implant in the uterus.
On the other hand, the medical team could prescribe certain medications to reduce excessive blood clotting, improve thyroid function, or prevent the immune system from working incorrectly for the embryo implantation.
To sum up, there are various treatment options available for women who have experienced recurrent implant failure. Therefore, it’s essential to carry out a proper diagnosis to find out where the root of the problem lies, and determine the most appropriate course of action in each case.
