The effect of hyaluronic acid-enriched transfer medium on the implantation rate in frozen-thawed embryo transfer cycles

Background: The treatment strategy for patients with a history of multiple failures in in vitro fertilization cycles remains a subject of active research. Embryo transfer in cryocycles is known to be more successful than “fresh” embryo transfer, when ovarian stimulation, follicle puncture, fertilization, and embryo culture were performed but the overall efficiency of in vitro fertilization cycles decreases with maternal age and transfer of poor quality embryos. One of the key factors influencing the failure of high quality embryo implantation is the deficiency of the adhesive matrix, which ensures the interaction between the embryo and the endometrium. The implementation of protocols that include the use of hyaluronic acid-enriched transfer media in the process of embryo transfer is a promising direction for improving implantation outcomes. Special attention of researchers is paid to determining the indications for the use of this technique.

Aim: The aim of this study was to evaluate the effect of hyaluronic acid-enriched transfer media on the pregnancy rate in cryocycles.

Materials and methods: This retrospective cohort comparative study, included 609 women who underwent controlled ovarian stimulation and frozen-thawed embryo transfer.

Results: The main outcomes of frozen-thawed embryo transfer cycles were analyzed, taking into account the quality of the transferred embryos and the use of hyaluronic acid-enriched transfer media. The latter was not shown to be associated with an increase in biochemical and clinical pregnancy rates in women under 35 years of age with a history of repeated implantation failures or after transfer of poor quality embryos. However, in patients over 40 years of age with poor quality embryos, the use of hyaluronic acid-enriched transfer media was effective, since it increased the clinical pregnancy rate. As expected, our data showed an increase in the clinical pregnancy rate in women with high quality embryos on the day of transfer, regardless of the patient’s age. At the same time, in patients with a thin (thickness less than 7 mm) endometrium or a history of miscarriage, the use of hyaluronic acid-enriched transfer media was also associated with an increase in the clinical pregnancy rate and live birth during embryo transfer in cryocycles.

Conclusions: The data obtained have shown that the use of hyaluronic acid-enriched transfer media in cryocycles may be recommended for women over 40 years of age, regardless of the quality of the transferred embryos, as well as for women of any reproductive age with a thin endometrium and a history of miscarriage when transferring good quality embryos.