At the present time, the most effective approach for preserving fertility is to freeze (or cryopreserve) sperm, eggs or embryos. Which one of these approaches is used depends upon individual circumstances.
Single men and women would typically freeze sperm and eggs, respectively. Clinical labs have extensive experience freezing sperm and it is a very effective approach for men to use before cancer treatment. There is less experience with freezing eggs, but major strides have been made with the development of newer freezing techniques known as vitrification.
If the woman is in a stable relationship, the favoured approach is to freeze embryos. This is because embryo freezing eliminates the uncertainties associated with post-thaw egg survival, egg fertilisation and subsequent embryo development.
For cancer cases, there is evidence that temporarily “shutting down” the ovaries using drugs known as GnRH analogues can protect eggs from chemotherapy. The evidence that GnRH analogues preserve ovarian function is strongest for breast cancer cases and GnRH analogues are now listed on PBS for this indication.