Leeton and Colleagues reported the first pregnancy after transfer of a donated embryo in a patient with primary ovarian failure. Now embryo donation is a well-established and successful form of assisted conception treatment where both partners are sub fertile. Embryo donation is an ethically and legally accepted form of treatment
1) Menopausal or premenopausal woman and sub fertile partner.
The subfertility of the male partner could be due to primary testicular failure or to a genetic disorder. The menopausal status of the female partner could be due to premature ovarian failure, gonadal dysgenesis, or ovarian failure secondary to chemotherapy, radiotherapy or surgical oophorectomy. This group of patients forms the majority of that seeking embryo donation. It is also these groups of patients that raise the most concerns about embryo donation, as the majority are older patients and at risk of age –related pregnancy complications, which also raise concerns about the welfare of any resulting children.
2) Recurrent IVF failures.
Older patients undergoing IVF- ET should receive adequate counseling about the likelihood of achieving a live birth. Those patients with reduced ovarian reserve or poor oocyte quality should be offered alternative treatments such as oocyte and embryo donation.
3) Carriers of genetic disease or chromosomal abnormalities.
Couples who are at risk of having children with severe disability, e.g. X- linked disorders, cystic fibrosis or repeated pregnancy loss due to chromosomal abnormalities are candidates for embryo donation .However, although antenatal fetal diagnosis is available for an increasing number of these conditions, termination of pregnancy remains un acceptable for many couples. Recent advances in preimplantation genetic diagnosis have enabled couples to undergo IVF, preimplantation embryo biopsy and the transfer of normal embryos. However, the high cost and complexity of this procedure put it beyond the means of many couples. This group of patients forms the smallest group of those who seek embryo donation.
The large majority of embryo donors are couples who have completed their families through IVF and have spare embryos cryopreserved. They volunteer to donate their spare embryos because they want to help infertile couples for whom they feel great sympathy. Embryo donors are carefully selected and screened.
The other source of donated embryos is by way of separate oocyte and sperm donation. Donation from infertile couples is less successful than form fertile volunteers; however, this is a more costly source of donors.
Donors are screened for Genetic and infectious diseases like HIV, HBSAg to prevent transmission to the recipient or the offspring.
Physical characteristics of the donor couple such as skin color, eye colour, hair colour and body build are matched as closely as possible to the characteristics of the intended recipient couple.
Transfer of donated embryos offers a good alternative for a select group of patients, mainly menopausal or premenopausal women with infertile or sub fertile partners. Other group of patients who will be benefit from this treatment include patients with recurrent failure at IVF treatment and couples with congenital and hereditary diseases.
This is an option for women with ovaries but no uterus. Such a situation could arise because of a congenital anomaly like mullerian agenesis or following hysterectomy.
A standard IVF regimen can be used and the ovum pick up done.
The surrogate mother is prepared as for a frozen embryo replacement cycle with hormone replacement therapy.
Preimplantation Genetic diagnosis (PGD)
This is the term given to the detection of genetic disorder in human embryos. It can be done by a biopsy of the polor body or the blastomeres of the embryo. This is useful only if the female partner is the carrier of the genetic defect. The extruded polor body does not contribute to subsequent development of the embryo and hence removal has minimal adverse effect on later development after fertlisation. The other option is embryo biopsy and is usually a blastomere biopsy. Usually when an embryo reaches the 6-12 cell stage, a single cell is subjected to genetic analysis. FISH or fluorescent in situ hybridization is the preferred technique to detect chromosomal anomalies like trisomies. PCR involves repeated amplification of DNA to obtain adequate genetic material and this helps in detecting single gene mutations like cystic fibrosis and sickle cell anemia.