Fertilization and early embryology: Preliminary experience with human oocyte cryopreservation using 1,2-propanediol and sucrose

Abstract

Feasibility of cryopreservalion of mature human oocytes using 1,2-propanediol and sucrose was studied initially utilizrng 1 and 2 day old unfertilized oocytes. Of these 285 aged oocytes 55% survived thawing, and 41% of 128 oocytes inseminated by single sperm intracytoplasmlc injection (ICSI) fertilized normally. Limited embryonic development occurred in 51% of these embryos (n = 27) observed for the next 4 days. Cryosurvlval of fresh donated oocytes (n = 81) was poorer (n = 20; 24.7%), while fertilization (n = 13; 65%) and embryo development (100%) was good prior uterine transfer on day 3. Eight oocyte recipient cycles were undertaken, in which cryopreserved donated oocytes were thawed and inseminated by ICSI. Five of these cycles reached embryo transfer, and three pregnancies were initiated though none went successfully to term. Oocyte cryopreservatlon will ultimately facilitate oocyte donation procedures; however, cryosurvival of fresh frozen oocytes must be improved to at least the degree observed with aged unfertilized oocytes.