Oocyte Survival After Vitrification With Slush Nitrogen Compared With Liquid Nitrogen

The study is a randomized, controlled trial which seeks to characterize oocyte survival rate following vitrification and subsequent warming with both slush nitrogen and liquid nitrogen. After warming, fertilization and embryology outcomes will be assessed.

Oocyte donors and a single donor sperm source will be utilized. Following enrollment, oocyte donors will undergo ovarian stimulation and oocyte retrieval. The mature (MII) oocytes obtained for each patient will then be assigned a number and randomized via block randomization to one of two treatment groups (liquid nitogen or slush nitrogen). Through block randomization, this will create a paired population of oocytes so that half of each patient's oocytes will undergo cryopreservation with liquid nitrogen and half will undergo cryopreservation with slush nitrogen. Timing of hyaluronidase stripping and vitrification will be consistent with current institutional clinical practice for oocytes.

Following cryopreservation, oocytes will be warmed and intracytoplasmic sperm injection will be performed and subsequent embryology outcomes tracked.