Human Reproduction, Vol. 14, No. 9, 2362-2366,
September 1999
© 1999 European Society of Human Reproduction and Embryology
Clinical experience with ultrarapid cryopreservation of human embryos resulting from intracytoplasmic sperm injection: Brief communication
1 Centre for Human Reproduction, Sinhá Junqueira Maternity Foundation, Rua D.Alberto Goncialves, 1500–14085–100 and 2 Department of Obstetrics and Gynecology, University of Ribeirão Preto (UNAERP), Ribeirão Preto, SP, Brazil
A total of 41 patients requested thawing of supernumerary embryos in an intracytoplasmic sperm injection (ICSI) programme. Mean patient age was 30.8 ± 3.8 years. Embryo freezing by the ultrarapid method was performed at room temperature in 3 mol/l DMSO and 0.25 mol/l sucrose. Total freezing time was 2.5 min including filling of the straw. In the thawing process, the embryos were removed from liquid N2, left at room temperature for 30 s, immersed for 40 s at 30°C, and then successively transferred at room temperature for 10 min to each of three sucrose solutions of decreasing concentration. The embryos were kept in culture and only those that presented cleavage after 24 h were transferred. Embryos from 42 cycles were thawed and a total of 24 transfers was performed. The mean number of thawed embryos was 5.0 ± 3.2 per cycle and the mean number of transferred embryos was 2.83 ± 1.3. The clinical pregnancy rate per cycle obtained after the thawing process was 16.6%. The clinical pregnancy rate per transfer was 29.2% and the implantation rate was 13.2%. The abortion rate was 14.3%. Six deliveries have been performed, with the birth of seven infants.
Key words: cryopreservation/human embryo/ICSI/ultrarapid method
3 To whom correspondence should be addressed at: Centre for Human Reproduction, Sinhá Junqueira Maternity Foundation, Rua D.Alberto Concialves, 1500–14085–100, Brazil