In-vitro fertilization success rates have steadily improved in the years since the first successful pregnancy through IVF which occurred in 1978. We have become very proficient with regard to the procedural components of IVF including ovarian stimulation to mature multiple eggs, removal of eggs from the body, fertilization of eggs in the laboratory, culturing of the embryos outside of the body, and placement of embryos in the uterine cavity (embryo transfer). Most patients who begin this process will successfully complete each of the phases of treatment and will have embryos transferred. However, following transfer of embryos to the uterus, there is a substantial failure of embryos to implant and continue to a live birth. Ongoing live birth rates following embryo transfer vary widely among different age groups and programs usually ranging from 30-70 percent. Looked at another way, 30-70 percent of patients who have successfully completed all phases of treatment will fail to achieve a live birth as a result of that treatment cycle. Clearly, improving embryo implantation rates is the key to further improvements in IVF success rates as we look into the future. A recent study suggests that traumatic injury to the uterine lining during an ongoing IVF cycle results in improved implantation.
Embryo implantation involves a complex interaction between embryo and uterus which includes the development of new blood vessels as well as the presence of a number of proteins, molecules, and growth factors. It is well understood that implantation requires an inflammatory response coupled with development of new blood vessels (angiogenesis). Since biopsy of the uterine lining results in inflammation and angiogenesis, this biopsy induced injury could produce a local environment between the embryo and the endometrium resulting in improved implantation.
A recent study from Taiwan looked at a small group of patients (6) who had undergone a telescopically guided biopsy of the back wall of the uterine cavity several days before their egg retrieval. They compared this group to a control group of 24 patients who received the same IVF preparation and treatment but did not have an endometrial biopsy. The pregnancy rate among the 6 patients who underwent telescopically directed biopsy was 100% while the group that did not undergo endometrial biopsy achieved a 46% pregnancy rate. The investigators concluded that site specific telescopically guided endometrial biopsy performed during the ongoing IVF treatment cycle significantly improved clinical outcome in patients who had experienced repeated implantation failure.
This study adds to the growing body of scientific literature which suggests that biopsy induced injury of the uterine lining around the time of embryo transfer improves implantation rates and clinical outcomes of IVF. While the timing and optimal location of this biopsy remains to be determined, the idea of induced endometrial trauma to improve implantation rates seems to hold great promise.
Reproductive Biology and Endocrinology 2011, 9:140