Oocyte Cryopreservation

Abstract

All of the techniques used in cryopre servation of embryos have been studied on oocytes of various animals⁽³⁾ such as mouse, rat, ⁽⁴⁾ hamster, ⁽⁵⁾ pig⁽⁶⁾ and cattle, ⁽⁷⁾with wide range of success. Extensive studies, however, have been done only in mouse oocytes, expan ding from the most immature primary follicles, ⁽⁸⁾ germinal vesicle stage,⁽⁹⁾up to matured ovul ating oocytes, with increasing orders of post thaw survival rates, even though the results are much lower than those of embryo cryopre servation. ⁽¹⁰⁾ 

From a practical standpoint, oocytes can be donated by volunteers, from patients under going laparoscopic sterilization, and women who are willing to donate their excess oocytes after IVF programme. ⁽¹⁾ A major difficulty in a donation programme consists in the synchrony between the ovarian cycles of donor and recipient. If this synchrony is not present at the time of donation, the oocytes can, if possible, be cryopreserved and then thawed at an appropriate time in the course of a subsequent cycle. The availability of an adequate oocyte cryopreservation pro gramme will increase the chance of establishing a donor programme.