Implantation Support Medium Transfer or ISMT is recommended as a means of improving the process of reception of transferred embryos in the womb, increasing chances of implantation.
What is ISMT?
After In-Vitro Fertilisation (IVF) has occurred, the fertilized eggs are placed in a dish, in an incubator that mimics the human body conditions. The developing embryos in the dish are surrounded by a liquid medium enriched with nutrients that support their survival and growth. As these first stages of life progress, the embryos, in turn, release some signals, or chemical cues, that are meant to prepare the uterus for accepting them. This is the process of implantation that takes place in the early weeks (around week 4) of pregnancy.
In ISMT, in order to increase the receptivity of the womb, we transfer some of the enriched embryo-conditioned medium, without the embryos, in the uterus 2-3 days before embryo transfer takes place. Preparing the endometrium (lining of the uterus) to support the transferred embryo(s), in some cases, may offer a much greater chance for a successful implantation.
Who may need an ISMT?
ISMT is beneficial for women that had a previously failed IVF after transfer of good quality embryo(s), which possibly means that implantation was not successful.
It has been shown* that the age of the mother may contribute in reduced womb receptivity, and therefore we highly recommend ISMT in women older than 37 years of age.
How is ISMT done?
It is performed by a doctor, exactly like an embryo transfer, but without the embryo(s). Briefly, your doctor, guided by ultrasound imaging, will insert a catheter (fine tube) through your cervix to the uterus. Through imaging the doctor will assess and identify the location where implantation is physiologically likely to occur. The embryo-conditioned medium is going to be released there to prepare the endometrium (lining of the uterus), 2-3 days before the actual embryo transfer.
The experience will be similar to the mock embryo transfer and these two procedures can be planned to happen exactly at the same time, if your case requires both.
It is normally a pain-free step that takes about 5-10 minutes to complete without the need for anesthesia or recovery time. You will be able to return to your daily activities as normally.
How does ISMT contribute in the success of assisted reproductive techniques?
In AAFC, we perform ISMT because we want to mimic the physiological process of implantation as closely as possible.
In difficult-to-implant cases and in women older than 37 years of age, we highly recommend this procedure. Current studies* have shown that the use of enriched embryo-conditioned media significantly improves the implantation rate following an IVF and / or Intra-Cytoplasmic Sperm Injection (ICSI) procedure.
However, ISMT has no effect on the quality of your eggs / sperm or embryos, and although it may improve pregnancy rates, it might not improve the rate of live births.
If you considering that ISMT should be part of your treatment, please discuss it with one of our specialists, who can advise you further.
* Urman B, Yakin K, Ata B, Isiklar A, Balaban B (2008).Effect of hyaluronan-enriched transfer medium on implantation and pregnancy rates after day 3 and day 5 embryo transfers: a prospective randomized study. Fertil Steril. 90(3): 604-12. (Pubmed; PMID: 17936283)