The complementary techniques in IVF (in vitro fertilization) are aimed at improving the pregnancy or birth rate. Currently, there is a debate about the clinical efficacy and safety of many of these techniques as they have not been proven. It is possible that some of them, over time, as more studies are published, may be considered effective.
The HFEA (Human Fertilisation and Embryology Authority, the UK body that oversees fertility treatments and research has published a document, with free, clear and unbiased information, explaining which are the most commonly used complementary techniques, their efficacy and safety.
-
PGS, PGT-A or preimplantational diagnosis
PGS or PGT-A, also called aneuploidy screening, consists of evaluating the chromosomal abnormalities of embryos before they are transferred. The objective is to reduce the number of embryo transfers a patient undergoes until a successful pregnancy is achieved.
Although it is a very promising technique, the systematic use of PGS remains controversial. PGS is an invasive technique that requires biopsy of the embryo (removal of several cells from the embryo), and it is estimated that up to 20% of healthy embryos may be lost.
Among the risks, there is the possibility of false positives or false negatives; and embryos may be damaged in the process of ICSI, embryo biopsy or embryo vitrification. As of today, this result is of uncertain significance, it is still too early to know the possible effect of this technique on the children born, and it does not increase the overall probability of a child being born. What it does decrease is the number of transfers and, although there is still no clear evidence, it could decrease the rate of miscarriage.
-
Time-Lapse or Embryoscope
Time-lapse (called Embryoscope by many) consists of taking serial photographs to observe the evolution of the embryos in culture in a continuous manner and without removing them from the incubator, to facilitate the selection of the embryos to be transferred. There are no known risks. Although the embryos are subjected to light beams to take pictures every few days and we do not know if this has any effect on them. There is no evidence yet that it improves the results, although not removing the embryos from the incubator may have a positive impact.
-
Freeze-all
Freeze-all consists of freezing all the embryos obtained in an IVF cycle for transfer in a subsequent cycle. It is based on the assumption that hormonal stimulation during IVF can damage the endometrium, decreasing the implantation rate and increasing the miscarriage rate. In addition, it may decrease the risk of ovarian hyperstimulation syndrome (OHSS) and low birth weight. The disadvantage is that in the freezing-thawing process some embryos may be lost, which makes it necessary to postpone the embryo transfer for one or two months. To date, there is no evidence that it improves the pregnancy rate.
-
Hyaluronic acid (Embryo Glue®)
Hyaluronic acid is a substance that can be added to the transfer medium and could facilitate embryo implantation, as it is naturally found in the uterus. There is a specific culture medium for transfer that incorporates this substance (Embryo Glue®). There are no risks associated with the use of this substance in the culture medium. Although more studies are needed, a systematic review in 2014 concluded that it increases the pregnancy and birth rate by 10%.
-
Scratching/endometrial scratching
Endometrial scratching consists of doing an endometrial biopsy the month before IVF treatment. This scratching could induce endometrial repair by the release of certain substances or by activation of certain genes that may favor embryo implantation. The risks are limited, but it could cause infection or damage the endometrium. There is no evidence of its benefit because there are few studies in its favor and of moderate statistical quality.