Vitrification of human blastocysts using cryoloops: clinical outcome of 223 cycles*
Source: Human Reproduction, Volume 18, Number 2, February 2003 , pp. 384-391(8)
Publisher: Oxford University Press
Abstract:BACKGROUND: The need to cryopreserve human blastocysts is increasing. The successful birth has been reported of a baby from a blastocyst vitrified using the cryoloop technique. The present study expands on this earlier report to confirm the effectiveness of this vitrification procedure. METHODS: In patients undergoing IVF at one of three clinics, supernumerary blastocysts on day 5 or 6 at various stages of development were vitrified using cryoloops. RESULTS: Of 725 vitrified blastocysts, 583 (80.4%) survived. After the transfer of 493 blastocysts in 207 cycles, 76 women (37%) became clinically pregnant. Among these women, 21 pregnancies ended in miscarriage, 23 healthy babies were born in 18 deliveries, and 37 pregnancies are ongoing. The survival rate of day 5 blastocysts (87%) was higher than that of day 6 blastocysts (55%), but implantation rates and pregnancy rates were not statistically significantly different. CONCLUSIONS: Clinical outcomes with 725 blastocysts and 207 transfers showed that vitrification using cryoloops is effective and practical for the cryopreservation of human blastocysts. Early blastocysts on day 5 seem to be the most suitable in terms of stage and age for cryopreservation, but developed and day 6 blastocysts can also be cryopreserved.
Document Type: Research Article
Affiliations: 1: Hiroshima HART Clinic, 5‐7‐10 Ohtemchi, Naka‐ku, Hiroshima, 2: Osaka HART Clinic, Snowcrystal 10F 2‐6‐20, Umeda, Kita‐ku, Osaka, 3: Tokyo HART Clinic, 1‐22‐2, Higashi, Shibuya‐ku, Tokyo and 4: Laboratory of Animal Science, College of Agriculture, Kochi University, Nankoku, Kochi, Japan
Publication date: February 2003
- Human Reproduction features full-length, peer-reviewed papers reporting original research, clinical case histories, as well as opinions and debates on topical issues. Papers published cover the scientific and medical aspects of reproductive physiology and pathology, endocrinology, andrology, gonad function, gametogenesis, fertilization, embryo development, implantation, pregnancy, genetics, genetic diagnosis, oncology, infectious disease, surgery, contraception, infertility treatment, psychology, ethics and social issues. The highest scientific and editorial standard is maintained throughout the journal along with a rapid rate of publication.