Oocyte Cryopreservation by Slow Freezing and Vitrification

Longitudinal Evaluation of Vitrification of Human Oocytes

This study seeks to evaluate whether the vitrification technique, as compared to the more traditional slow-cooling technique, leads to higher rates of successful thawing, fertilization, implantation and delivery.

Cryopreservation (freezing) of human gametes (unfertilized egg) provides a great potential to preserve or extend fertility in the face of disease and social circumstances (cancer diagnosis, delaying childbirth, single women, etc.). There are two methods for storage of oocytes (unfertilized eggs): slow freezing or vitrification (uses higher concentrations of cryoprotectant and faster cooling rates). Slow freezing is the standard method and has been successful for embryos since 1983 and more recently for oocytes. Recent reports indicate that vitrification may be more successful than slow freezing. The aim of this study is to examine the rate at which frozen eggs survive freezing and thawing, the rate at which the frozen/thawed eggs fertilize with sperm and the pregnancy outcomes of oocyte (egg) vitrification cycles to determine whether the outcomes are similar or better than standard oocyte (egg) cryopreservation (freezing) cycles.

Inclusion Criteria:

• Age between 21 and 50 years, at the time of informed consent.
• Subjects must agree to undergo intracytoplasmic sperm injection (ICSI)

Exclusion Criteria:

• Presence of any medical condition that contraindicates ovarian stimulation, in vitro fertilization or pregnancy.