KOLKATA SURROGACY & OOCYTE BANK

OOCYTE FREEZING

Female Fertility preservation is receiving increasing attention as an evolving area of reproductive medicine. It aims to preserve reproductive tissue (Oocytes) for future use.

Oocyte VitificationTechnique:

Preservation of reproductive tissue is achieved through cryopreservation. Cryopreservation refers to the cooling of cells and tissues to sub-zero temperatures in order to achieve complete cessation of biological activity. The temperature that is generally used for the storage of mammalian cells is – 196°C, the temperature of liquid nitrogen.

Advantages of Oocyte Vitrification (Oocyte Freezing)

  • It provides women with greater choice and control of future reproductive potential.
  • It provides women without a male partner a viable option of preservation and is also opening up opportunities for non- medically indicated or ‘social’ fertility preservation aimed at combatting age-related fertility decline.
  • Further, in contrast to embryo preservation, the use of which requires consent from the storing partner, oocyte cryopreservation allows a woman complete autonomy in her decision-making regarding any future treatment or disposal.
  • It also overcomes religious or ethical objections associated with embryo preservation held by some women.

Does Vitrification have any effect on the oocyte quality?

  1. Documented survival rates range from 74.5% to 96.9%. It is also encouraging to note that when comparing ‘fresh’ oocytes with vitrified oocytes, there does not appear to be any demonstrable difference between fertilisation, cleavage or blastocyst formation rates.
  2. Notably, pregnancy success rates following the use of vitrified oocytes have been reported as comparable with those using ‘fresh’ oocytes, without any increased risk of aneuploidy or congenital anomalies. Indeed, increasing numbers of successful pregnancies are being achieved following oocyte vitrification.

What is the right time for freezing your oocytes?

Studies indicate that the earlier you freeze you oocytes the greater are the chances of taking home a baby later on.

Given that there is a progressive loss of both oocyte quality and quantity associated with female ageing, the success associated with this technology is undoubtedly influenced by the age of the woman at the time of preservation.

Rienzi et al. report dramatically diminished results in women >38 years of age, with each year of maternal age decreasing the delivery rate by 7%. Thus, Women interested in preserving fertility to counteract future ovarian ageing need to be informed that the chances of success are likely to improve when oocytes are harvested and cryopreserved at a younger age, when oocyte quality is better.

Who can benefit from Oocyte Freezing?

  1. Women requiring chemo radiation involving the ovaries.
  2. Genetic diseases like turners, fragile x syndrome as they are associated with premature ovarian insufficiency.
  3. Women undergoing reproductive tract surgery, eg for ovarian tumours or endometriotic cysts.
  4. Women wishing to defer childbearing for ‘social’ reasons.

1. Fertility preservation before Chemotherapy

Advances in cancer therapy have increased the number of women surviving a diagnosis of malignancy. Unfortunately, many such treatments are toxic for ovaries and, as such, public and professional attention to fertility preservation for these women is growing.

Patients undergoing chemotherapy or radiotherapy for a variety of non-malignant conditions, including autoimmune connective tissue disease and haematological conditions may also benefit.

2. Fertility preservation associated with genetic conditions

Several genetic mutations are associated with Premature Ovarian Insufficiency. These often affect the X chromosome.

Although, fertility preservation for women with genetic conditions is possible, it is not without controversy. Such women are at risk of resultant aneuploidy or abnormal number of chromosomes in the offspring. While pre-implantation genetic diagnosis may help offset this risk, it does not negate the fact that some conditions such as Turner syndrome are associated with medical comorbidities that may actually preclude carrying a pregnancy. Any decision regarding future pregnancy therefore needs to be carefully considered with appropriate counselling.

3. Fertility preservation before Ovarian Surgery:

Ovarian surgery for benign conditions including endometriosis may diminish ovarian reserve. Several studies report a lower ovarian reserve after ovarian surgery, especially in patients with endometrioses. This may result from incidental cutting of normal ovarian tissue during cyst removal or result from damage of healthy ovarian tissue by electro cautery.

Fertility preservation procedures should therefore be considered before complex or repeated ovarian surgery in women wishing to conceive in the future.

4. Non-medically indicated ‘social’ fertility preservation

Most recently, ‘social’ fertility preservation has been assuming increasing importance. In today’s society, where increasing professional and financial opportunities are available to women, many are delaying childbearing. Given that female fertility progressively declines with age, delayed childbearing undoubtedly affects a woman’s opportunity for pregnancy. With assisted reproduction unable to fully overcome the effect of ageing on fertility loss, fertility preservation is an evolving technology that offers the potential to combat subfertility secondary to ovarian ageing.

For enquiry call: 033-66-398-604.