Clinical Review ABC of subfertility

Further advances and uses of assisted conception technology

BMJ 2003; 327 doi: https://doi.org/10.1136/bmj.327.7424.1156 (Published 13 November 2003) Cite this as: BMJ 2003;327:1156
  1. Susan Pickering,
  2. Peter Braude

    Introduction

    Assisted conception technology has led to a variety of new techniques that can help subfertile couples. However, many now go beyond simply improving the capacity to procreate. They also affect areas outside reproductive biology and present new ethical dilemmas.


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    During cooling of an oocyte for cryopreservation, the normal metaphase spindle (left) can become dismantled (right), which could result in the production after fertilisation of a karyotypically abnormal embryo

    Preserving fertility for young women

    Long term survival rates for cancer have improved substantially because of the use of aggressive chemotherapy and radiotherapy. However, in young women this comes at a price—many women lose ovarian function because oocytes or their support cells are damaged by the treatment. A technique ensuring successful cryopreservation of oocytes would benefit women recently diagnosed with cancer who want to retain their fertility potential. In addition, cryopreservation could help women with a family history of premature menopause as they could store their gametes before their pool of oocytes is depleted.

    Cryopreservation of oocytes

    In contrast to the success of embryo freezing, which is now a routine procedure in most in vitro fertilisation clinics, cryopreservation of oocytes has been less successful. Only a few live births after egg freezing have been achieved since the first one in 1986. Some problems have been reduced by improving cryoprotectant regimens and by using intracytoplasmic sperm injection to overcome the block to fertilisation, resulting in a few pregnancies and live births. However, the success rate remains low—about 1 in 100 eggs that are frozen results in a live birth.


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    Live births after egg freezing are rare and can make headline news

    Cryopreservation of ovarian tissue and maturation of oocytes and follicles in vitro

    An alternative approach is cryopreservation of slices or biopsies of ovarian tissue, which contain many thousands of immature oocytes. These oocytes are quiescent and their chromatin is in a stable phase of meiosis.

    Autografting and in vitro maturation could be …

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