What happens during donation?
Embryos are transferred into the recipient’s uterus, usually within three to five days after the eggs are fertilized in the laboratory. The embryo transfer is performed by placing a small catheter with the embryos through the cervix and into the uterus. If the recipient couple has extra embryos, these embryos may be cryopreserved (frozen) for use at a later time in additional attempts to achieve a pregnancy.
Who receives donated embryos?
The use of donated embryos may be considered by women with untreatable infertility that involves both partners, untreatable infertility in a single woman, recurrent pregnancy loss thought to be related to the embryo, and genetic disorders affecting one or both partners.
How should recipients be evaluated?
Evaluation of the recipients is similar to that of patients undergoing routine IVF:
- This should include a comprehensive medical history from both partners including blood type and Rh factor.
- Testing for sexually transmitted diseases including HIV, hepatitis, gonorrhea, chlamydia and syphilis.
- Recipients should be counselled by a mental health professional about the complexity of the decision to use donor embryos.
- The recipient should have a pelvic exam and an assessment of her uterus (womb).
- If she is over 45 years old, a more thorough evaluation should be done, including an assessment of heart function and risk of pregnancy-related diseases. She may also be advised to see a doctor who specializes in high-risk pregnancy.
How is the recipient prepared for the embryo transfer?
In order for embryos to implant into the recipient’s uterus, the endometrium (uterine lining) must be prepared and synchronized with the donor reproductive cycle. Numerous methods of endometrial preparation have been described; however, the principle of hormonal preparation is similar. Women who have ovarian function are given a GnRH-a to temporarily suppress their menstrual cycle. When the donor starts her hormonal medications to stimulate her ovaries, the recipient is given estradiol to stimulate the endometrium to develop. Ultrasound assessment of the endometrium and blood tests may occur during this time. The recipient begins progesterone on the day after the donor receives HCG. Progesterone causes specific maturational changes within the endometrium that enable the embryo to implant.
How are the embryos screened for disease?
The Food and Drug Administration (FDA) has strict guidelines for the testing of people who are donating tissue, including eggs, sperm and embryos. However, as most embryos that are donated were originally intended to be used by the people who created them, the FDA-recommended testing may not have been performed within the appropriate period. The embryos may still be donated as long as the recipients are aware of the risks. At the time of donation, the donors should provide a tested for communicable diseases including HIV, hepatitis, syphilis, gonorrhea and chlamydia. If the donors are unavailable or refuse to be tested at the time of their donation, the recipients are warned about the chances of disease transmission.
What risks are there with embryo transfer?
There are minimal risks associated with the embryo transfer procedure. They include the loss of the embryos during transfer or implanting the embryos in the wrong place such as the fallopian tubes. Although some women experience mild cramping, the procedure is usually painless.
How successful is embryo donation at achieving pregnancy?
Success rates with embryo donation depend on the quality of the embryos at the time that they were frozen, the age of the woman who provided the eggs and the number of embryos transferred.