Hyaluronic acid can successfully replace albumin as the sole macromolecule in a human embryo transfer medium

Objective: To examine the effect on pregnancy and implantation rates when highly purified, fermentation-based hyaluronic acid was the only macromolecule supplement to the transfer medium in a human IVF program. Design: Prospective randomized study. Setting: In vitro fertilization center in an academic medical institution. Patient(s): Eighty patients were included in this prospective randomized double blind study. Inclusion criteria were age ≤35 years, the availability of at least three embryos eligible for transfer on day 3 after fertilization, and no more than three previous embryo transfer attempts. Intervention(s): All embryos were cultured in P1 medium containing 10% synthetic serum substitute (SSS) until day 3. Patients were randomly allocated to two groups; in treatment group A (40 patients), embryos were transferred to P1 medium supplemented with 0.5 mg/mL hyaluronic acid for 5-10 min before their intrauterine transfer. In the control group B (40 patients), embryos were transferred, as routinely performed, in P1 medium containing 10% SSS. Main Outcome Measure(s): Clinical pregnancy and implantation rates. Result(s): The mean age of the female partner was 28.7 ± 3.3 years and 29.7 ± 3.8 years for groups A and B, respectively. In group A, 103 embryos were transferred and in group B, 97 embryos were transferred for a similar mean number of 2.6 ± 0.6 and 2.4 ± 0.5 embryos/transfer, respectively. Twenty-five pregnancies were achieved in group A, and 21 pregnancies in group B. This led to a comparable clinical pregnancy and implantation rates of 62.5% and 34% as compared to 52% and 26.8% for groups A and B, respectively. Conclusion(s): Hyaluronic acid can successfully replace albumin as a sole macromolecule in a human embryo transfer medium and result in high pregnancy and implantation rates. The use of this supplement is an important step in the development of human embryo culture media free of blood-derived additives.