Donor Oocyte Therapy
Healthy donor eggs and embryos can make dreams come true, and our specialists are here to help make that process possible.
Eggs (oocytes) from younger women possess greater fertility potential, and this potential is utilized in donor egg therapy. In this therapy, eggs from another woman (the donor) are fertilized with the patient's partner or donor’s sperm, and the resultant embryos are placed in the recipient's uterus. Research has shown that the age of the female partner is the single most important factor in predicting the success of IVF and other assisted reproductive therapies. For patients under 30, success rates range from 30 to 50 percent. Patients older than 40 can only expect a realistic success rate of 5 to 15 percent. The eggs are stimulated and retrieved from the donor using a similar regimen of drugs that a woman using her own oocytes for in-vitro fertilization-embryo transfer would be given. The donor may be known to and recruited by the recipient (non-anonymous donation), or instead may be unknown to the recipient, having been recruited by the IVF-ET program (anonymous donation). In cases where the eggs of a donor under the age of 35 are used, a high success rate, one that could be compared to rates in women of similar age using their own oocytes, can be expected.
Donor Oocyte Therapy
In recent years, with the standardization of IVF-ET techniques and the development of ICSI (intracytoplasmic sperm injection) for severe sperm disorders, it has become clear that the single most important factor in predicting the success of IVF-ET is the age of the female partner. For patients under 30, success rates of 30-50 percent per oocyte retrieval can legitimately be expected; for patients over 40, realistic success rates are only 5 percent to at most 15 percent. Oocytes from younger women possess greater fertility potential, and this potential is utilized in donor oocyte therapy. In this therapy, oocytes from another woman (the donor) are fertilized with the patient's (the recipient) husband's sperm, and the resultant embryos are placed in the recipient's uterus. The oocytes are stimulated and retrieved from the donor using routine IVF-ET techniques. The donor may be known to and recruited by the recipient (non-anonymous donation), or instead may be unknown to the recipient, having been recruited by the IVF-ET program (anonymous donation) or via the use of a donor oocyte agency. In cases where a young (less than 35 years old) donor is utilized, high success rates, comparable to those achieved in women of similar age using their own oocytes, can be expected.
Candidates for Donor Oocyte Therapy
There are three main indications for donor oocyte therapy. One is ovarian failure, which can be due to a wide variety of different causes, including radiation, chemotherapy, surgical removal of the ovaries, and a variety of disease states which cause or are associated with ovarian failure. Another indication is for women who carry some serious genetic disease who wish to diminish the chances that the disease will be passed on to their offspring. The third, and most common indication, is for women whose age is sufficiently advanced that their fertility potential is impaired significantly.
Laboratory Testing and Genetic Screening
Approximately one month before initiating every treatment cycle, the oocyte donor undergoes a very thorough battery of tests for sexually transmitted diseases. Obviously, by screening for sexually transmitted diseases, we seek to minimize the chances that such a disease will be passed from the donor to the recipient (and possible fetus) by the oocyte donation process. Despite these thorough precautions, there remains a very small risk of transmission of disease from donor to recipient. In addition to sexually transmitted disease testing, the donor's blood type will be determined. The donor's blood type may be a factor in making the match between donor and recipient (see below).
In addition, donors have a very thorough evaluation of their medical and family history. The donor is required to fill out a multi-page form detailing her family history. This form and other aspects of the donor's genetic and medical history are reviewed thoroughly by the administrators of the oocyte donation program prior to acceptance of the donor in the program. Even with this intensive screening, there remains a small risk that a baby resulting from the oocyte donation process will suffer from a genetic disease. Overall, the risks that a baby conceived through the oocyte donation process will have some birth defect, trivial or catastrophic, genetic or non-genetic, are the same as they are for the human population as a whole, namely 3-5 percent.
Matching Donor and Recipient
We understand that choosing to receive donated oocytes carries with it a simultaneous giving up of hope for pregnancy with one's own oocytes, and this can be a feeling of great loss. There are probably many characteristics that you hope your oocyte donor will possess, and you probably hope that your oocyte donor will possess many of your characteristics. We will do what we can to select a donor who meets your most important expectations, but you must understand that we will always face certain limitations. One requirement of our anonymous donation program is that anonymity be maintained. In order to accomplish this, we are limited in the amount of information that we can give you about the donor. We cannot tell you much more than the donor's height and weight, hair color and eye color, race, blood type, age, and duration of formal education. You have the right to be as specific as you like about the characteristics of the donor, but you need to understand that the more specific you are, the longer the entire process may be delayed. Obviously, if your criteria are extremely specific and detailed, we may never find a donor who meets your expectations. It is the impression of the director of the donor oocyte program that women who agree to donate their oocytes tend to be upbeat, energetic, resilient, and altruistic. If they did not have these personality characteristics, they probably would not be willing to undergo the discomfort and risks involved in oocyte donation in the first place. Thus, to at least a small extent, the process of oocyte donation tends to select for women with these favorable personality characteristics. Many of our donors are students in good standing in one of the schools of the UT Health Science Center.
The blood type of the recipient, donor, and recipient's husband are factors that can play some role in the matching process. Blood typing at its most basic level is defined by two separate typing systems. One is referred to as the ABO system. Four different types exist in this system, A, B, AB, and O. The other basic blood typing system is the Rh type. Only two Rh types are common, positive and negative. Thus, a routine blood type is described as one of the four ABO types and one of the two Rh types. The main element of the blood typing system which has the potential to affect the health of a pregnant woman's baby is the Rh type. Serious compromise of the baby's health can occur when an Rh negative woman is carrying an Rh positive fetus. With modern obstetrical treatment, such complications are uncommon, but they still exist. There are two ways an Rh negative woman can have an Rh positive baby. One is if the father of the baby is Rh positive and the baby inherited Rh positivity from the father. The other way this can happen is if an Rh negative woman receives an oocyte from a donor who is Rh positive, and the genetic makeup of the oocyte confers Rh positivity on the resulting fetus. Thus, practically speaking, the main situation in which the blood type of the egg donor can pose increased risk for the recipient is when both the recipient and her husband are Rh negative. In this circumstance, the use of an Rh positive egg donor would expose the recipient's fetus to a risk of Rh incompatibility that would not have existed had the woman used her own eggs or received eggs from an Rh negative donor.
Differences in ABO type between mother and fetus pose little risk to the health of the fetus. Therefore, use of an oocyte donor whose oocyte might produce a pregnancy which is different from the ABO type of the recipient and husband is not such a serious medical matter. Although ABO incompatibility is of negligible importance medically, we understand that to some recipient couples it may still be an important factor to match, so that genetically impossible differences in ABO type between parents and child are not revealed later in life.
Treatment of the Oocyte Donor
In general, stimulation of the oocyte donor's cycle is brought about using a similar regimen of drugs that a woman using her own oocytes for in vitro fertilization-embryo transfer is commonly given. Late in the cycle which precedes ovarian stimulation, the donor is started on daily treatment with one of two drugs, Lupron ® or Synarel®, generally the former or they may be treated with GnRH antagonists (Cetrotide® or Ganirelix®) later in the stimulation. Daily injections of Lupron® will continue for a total of nearly three weeks. After the donor's period has started, daily injections of a pharmaceutical gonadotropin preparation, such as Menopur®, Bravelle®,®Gonal-F® and Follistim®, will be added to the daily Lupron® injections. Generally, the donor will receive daily gonadotropin injections for a total of seven to twelve days. If the protocol is for GnRH antagonists (Cetrotide® or Ganirelix®) they will be started later in the stimulation cycle and will be used instead of Lupron®. During the time that the donor is receiving the gonadotropin injections, she will have frequent vaginal ultrasound examinations and blood drawing for determination of estradiol (E2) level. When ultrasound and blood testing indicate that development of the follicles (follicles are the ovarian structures that contain the oocytes) is optimum, the donor receives an injection of a different pharmaceutical called human chorionic gonadotropin (hCG). Thirty-five hours after hCG injection, oocyte retrieval is performed. We will need a sperm specimen from the recipient's partner on the day of the retrieval, because the oocytes are inseminated on this day. Transfer of fertilized eggs (embryos) to the recipient's uterus is generally performed three to five days after the oocyte retrieval.
Treatment Regimen for Recipients
In general, we try to arrange for recipients to have a "fresh" as opposed to frozen embryo transfer. In order to do this, the recipient's cycle must be manipulated to synchronize her with the donor. A combination of two or three hormonal medications is used to modify the recipient's cycle.
Recipients who ovulate and have regular menstrual cycles and menstrual bleeding on their own will start with a medication which suppresses their own cycle. Either the drug Lupron® (which is given as a subcutaneous injection) or Synarel® (which is sniffed) can be used for this purpose. A few days before the recipient's period is expected to start, she is started on Lupron®. One to three days after her period starts the recipient will begin taking oral estrogen daily in addition to the Lupron®. The formulation of estrogen which works best for our purposes is Estrace® 2 mg. The recipient will take Lupron® and Estrace® 2 mg, -1 tablet daily while waiting for the donor's cycle to come into synchrony with hers. When the donor's cycle has "caught up" with the recipient's, a simulated (artificial) 28 day menstrual cycle will be created in the recipient with the hormonal medications. To do this, the recipient takes an increased dose of Estrace® for 14 days. Sometimes we perform blood tests for hormone levels and/or an ultrasound on day 12 or 13 of the cycle to ensure an appropriate response. Lupron® treatment will continue throughout this time. On cycle day 15, that is, after the recipient has completed the fourteen days of Estrace®, progesterone treatment is begun. Progesterone is given either as a daily intramuscular injection of a preparation of progesterone in oil, or as twice daily doses of micronized progesterone, which is placed in the vagina. On the same day that progesterone treatment is begun, Lupron® is discontinued. The recipient will continue taking Estrace® and progesterone until the day her pregnancy test is performed. The embryo transfer will be performed anywhere between cycle day 15 and 20, but generally on cycle day 17 or 18 (cycle day 17 or 18 is the third to fifth day of progesterone administration). A sensitive blood pregnancy test will be performed on the 12th day after embryo transfer. If the recipient is pregnant, Estrace® and progesterone treatment will be continued for several more weeks.
Recipients who have complete ovarian failure and have no spontaneous menstrual cycles will not have to take Lupron®, but otherwise will take the same regimen of medications just described.