A woman can get pregnant with another woman’s egg, a process known as third-party reproduction or egg donation. This allows individuals or couples to achieve pregnancy when the intended mother cannot use her own eggs. The donor’s egg is fertilized outside the body, and the resulting embryo is transferred into the recipient’s uterus. The recipient carries and gives birth to the child, even though the egg originated from a different woman.
The Biological Mechanism of Transfer
The foundation for this type of pregnancy is In Vitro Fertilization (IVF), beginning with the donor’s ovarian stimulation. The donor receives hormonal injections to encourage the ovaries to produce multiple mature eggs. Once ready, a minor surgical procedure called egg retrieval is performed using an ultrasound-guided needle to collect the eggs from the follicles.
The retrieved eggs are taken to a laboratory where fertilization occurs. They are combined with sperm, typically from the recipient’s partner or a sperm donor, to create embryos. The embryos are monitored for several days until they reach the blastocyst stage, which is the optimal time for transfer.
The resulting embryo is placed into the recipient’s uterus via Embryo Transfer (ET). The recipient’s body is prepared using hormone medication that thickens the uterine lining. A small, flexible catheter gently deposits the embryo directly into the uterus, initiating a successful pregnancy. This sequence allows the recipient to experience gestation and childbirth without producing a viable egg.
Medical Reasons for Seeking Donor Eggs
Diminished ovarian reserve, often linked to advanced reproductive age, is a common reason for seeking donor eggs. As a woman ages, the quantity and quality of her eggs naturally decline, lowering the chance of conception and increasing the risk of chromosomal abnormalities. Using eggs from a younger, healthy donor bypasses these age-related challenges.
Premature ovarian insufficiency (POI), where the ovaries cease to function normally before age 40, is another indicator. This condition results in irregular or absent menstrual periods and low estrogen levels. Since the ovaries are no longer releasing viable eggs, donor eggs become the only option for a biological pregnancy.
Egg donation is also utilized when a woman carries a serious genetic disorder she wishes to avoid passing on. Using a screened donor egg eliminates the risk of transmission, even if her ovaries function normally. Furthermore, women who have undergone multiple unsuccessful IVF cycles due to poor egg quality or recurrent implantation failure frequently turn to donor eggs to improve their chances of a live birth.
Defining the Parental Roles
The use of a donor egg distinguishes between the woman who contributes the genetic material and the woman who carries the pregnancy.
Genetic Mother
The Genetic Mother is the egg donor, contributing 50% of the child’s nuclear DNA. The child inherits physical traits and genetic predispositions from the donor, as her egg forms the foundation of the embryo.
Gestational Mother
The Gestational Mother receives the embryo and carries the fetus to term. She provides the entire uterine environment crucial for development. The gestational mother also contributes a small amount of mitochondrial DNA, which is inherited exclusively from the person who carries the pregnancy.
Social and Legal Mother
This is the woman who intends to raise the child and is legally recognized as the parent. A clear legal contract ensures the donor relinquishes all parental rights and responsibilities. The gestational mother’s womb influences the developing fetus through environmental factors, a concept known as epigenetics, which can affect how inherited genes are expressed.
The Donor and Recipient Process Steps
The process begins with rigorous screening of the egg donor to ensure the safety and health of the resulting pregnancy. Donors undergo extensive medical evaluations, including hormonal testing and screening for infectious and genetic diseases. A psychological evaluation is also conducted to confirm the donor understands the implications of the donation and the relinquishment of future rights.
For the medical procedure to be successful, the donor’s cycle and the recipient’s uterine cycle must be carefully synchronized. The recipient’s endometrium, or uterine lining, must be at the precise stage needed for the embryo to implant. This synchronization is achieved using hormonal medications for both women, often starting with birth control pills to regulate their cycles.
The recipient is given estrogen medication for about two weeks to thicken the uterine lining. Progesterone supplementation follows to make the lining receptive, mimicking the hormonal environment of a natural early pregnancy. The embryo transfer is timed to coincide with the donor’s egg retrieval and fertilization, ensuring optimal preparation for implantation.