Egg donation involves using a donor egg, fertilizing it with sperm in a laboratory, and then transferring the resulting embryo into the intended mother’s uterus. This process offers a pathway to pregnancy for individuals and couples facing fertility challenges. Achieving a confirmed pregnancy requires understanding the carefully controlled medical and biological timeline, which moves through distinct phases from preparation to confirmation.
Preparing the Recipient for Embryo Transfer
The initial phase focuses on medical clearance and preparing the recipient’s uterus for the embryo. A thorough evaluation is completed, including blood tests, infectious disease screening, and a uterine assessment (often via saline sonogram). This assessment checks for abnormalities that could interfere with implantation and ensures the recipient is physically ready for the hormonal regimen.
Hormonal preparation is initiated to build a thick, healthy endometrial lining where the embryo will implant. The recipient begins taking estrogen, typically for two to three weeks, to encourage the uterine lining to thicken. Physicians monitor progress with regular ultrasounds, aiming for an endometrial thickness generally between 8 and 12 millimeters, which is optimal for successful implantation.
Once the lining reaches the desired thickness, the hormone progesterone is introduced. Progesterone causes a final maturation of the endometrium, signaling the uterus to enter the “implantation phase” or window of receptivity. The embryo transfer is precisely timed to occur a specific number of days after progesterone is started, mirroring the natural timing of an embryo entering the uterus.
The Embryo Transfer and Critical Two-Week Wait
The embryo transfer procedure is a quick, non-surgical event, similar to a routine gynecological exam. A physician uses a thin catheter to gently place the embryo, usually at the Day 5 blastocyst stage, into the prepared uterine cavity. Following the transfer, the recipient continues prescribed hormonal medications, particularly progesterone, to sustain the uterine lining and support early pregnancy.
The period immediately following the transfer is known as the “two-week wait,” though the actual duration is often 9 to 14 days. During this time, the embryo attempts to hatch and implant into the receptive endometrial lining. Successful implantation triggers the production of human chorionic gonadotropin (hCG), the pregnancy hormone, by the developing placental tissue.
The waiting period concludes with the Beta hCG blood test, which measures the level of the hormone in the bloodstream. This blood test is the most accurate way to confirm pregnancy, as home urine tests are unreliable due to lower sensitivity. A positive Beta test, typically scheduled 9 to 14 days after the embryo transfer, provides official confirmation of pregnancy.
Variables That Affect the Overall Timeline
While the steps following the embryo transfer are consistent, the total time from initial consultation to the transfer date varies significantly. This variability is largely determined by whether a fresh or frozen egg donation cycle is used.
A fresh cycle requires synchronizing the menstrual cycles of both the egg donor and the recipient using hormonal medications. This coordination adds complexity and time, as the donor must undergo ovarian stimulation and egg retrieval. This process can take two to three months from the time a match is made. The recipient’s preparation must be perfectly timed with the donor’s retrieval to ensure the uterus is ready for the fresh embryo.
A frozen egg cycle is faster because the donor eggs have already been retrieved, fertilized, and cryopreserved, or are available for immediate thawing. This eliminates the need for synchronization and donor-side medical procedures, making the timeline more predictable. The recipient can proceed with hormonal preparation as soon as medically cleared, often allowing for an embryo transfer within six to eight weeks of starting the process.
Transitioning to Prenatal Care
A positive Beta hCG test marks the transition from the fertility clinic to standard obstetrical care. The clinic will repeat the Beta hCG blood test every two to three days to confirm that hormone levels are rising appropriately, ideally doubling every 48 to 72 hours. This serial testing provides reassurance that the pregnancy is progressing as expected.
The first ultrasound is typically scheduled around six to eight weeks of gestation to confirm a gestational sac and fetal heartbeat. Once a viable pregnancy is confirmed and stable, usually between eight and ten weeks of gestation, the recipient is formally “graduated” from the fertility clinic. The recipient is then transferred to the care of a general obstetrician or specialist, who manages the remainder of the prenatal care.