9th & 10th February 2008
KATRIYA hotels and towers - Hyderabad, India.
Cryopreservation of the embryos is an important component of routine assisted reproductive programs (IVF). Cryopreservation of surplus embryos increases the opportunity for patients to conceive and improves the cumulative pregnancy rates. Recently, IVF centres in many countries have reduced the number of embryos that are transferred into the uterus to two or even one. With this, many embryos are available for freezing. Efficient embryo cryopreservation has several advantages. It helps to reduce costs and increases cumulative pregnancy rates. It can also help in cases of cancelled ET during fresh cycles due to ovarian hyperstimulation syndrome, or difficult ET.
However, current experience in the literature reveals less than satisfactory post-thaw survival, implantation, and live birth rates. To improve the outcome, we have modified the various steps of freezing and thawing for better outcomes (Suresh Kattera and Christopher Chen: A modified embryo cryopreservation method increases the post-thaw survival with a concomitant increase in implantation. Fertility and Sterility 2005, 84; 1498-504).
Recently, we have achieved a clinical pregnancy of 53% with a live birth rate of 36% with our modified slow freezing method. Some centres who follow our method have achieved similar or even higher clinical pregnancy rates for day 2 or 3 embryo transfers (one Centre in Spain reported a 63% clinical pregnancy for day 2 embryo transfer -Personal communication).
By contrast, vitrification, which is an ultra-rapid method for freezing embryos, is being considered as an alternative to the slow freezing method. It should be noted that vitrification protocols are starting to enter the mainstream of human ART. Vitrification is relatively simple, and relies on the placement of the embryos in a very small volume of vitrification medium that must be cooled at extreme cooling rates not obtainable in regular enclosed cryostraws and cryovials. During the workshop, we will demonstrate both slow freezing and vitrification methods and hands-on practice will follow. |
