Human egg freezing is rapidly becoming a vital tool in Assisted Reproductive Technology. Candidates for egg freezing include women without partners who wish to preserve their fertility; cancer patients at risk of losing fertility from chemotherapy; and donor egg recipients. While in the past, egg freezing has not been as successful as embryo freezing in producing live births, recent experience in several centers has demonstrated significant improvement, with pregnancy rates comparable to those achieved with frozen embryos. The purpose of this study is to determine the best method to freeze eggs. We shall be seeking volunteers from the egg donor program, since young, fertile donors represent the best model to study the effect of egg freezing.~We plan to enroll 12 recipients and 6 donors in this study. Each egg donor will go through a stringent screening process (medical, genetic and psychological). Eggs retrieved from all donors will be split in half: one half will be frozen by the slow freeze method, and the other half by vitrification. Each of the six donors will be paired with two recipients; each recipient will be assigned half the total eggs frozen. For each recipient, half of the eggs will come from the slow freeze group and the other half will come from vitrification.~When the recipient's uterine lining is deemed ready (following estrogen treatment and ultrasound monitoring), thawing will be performed on eggs frozen by either the slow freeze or the vitrification method. The thaw process will be randomized between the two types of freezing. One sperm will be injected into each egg that survived the freeze. Fertilization and embryo development will be recorded. Ideally, two embryos will be transferred into the recipient's uterus. Pregnancy will be determined by a blood test and followed by serial blood tests and ultrasound.~The study will determine which freezing method yields better survival and pregnancy rates.
The purpose of this study is to determine the best way to freeze eggs in order to preserve the fertility potential of young women.