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Endometrial preparation for embryo transfer in donor egg ivf


Using frozen donor eggs from an egg bank, such as we have at OvobankID, can have several advantages over using a fresh donor, and one of these is that the donor and the recipient do not need to have their cycles synchronized. Indeed, the intended parents can plan the procedure for their convenience, and it (usually) means they do not have to wait.

Although in egg donation procedures, the intended mother (or gestational surrogate) does not have to undergo ovarian stimulation, they still need to have hormonal treatment to prepare their body to receive the embryo and maximize the chances of success.

When the frozen donor eggs, previously chosen carefully and shipped safely to your clinic, are ready to be used, they are thawed and fertilized with sperm from the partner (or donor sperm if required) to form embryos. These embryos are carefully grown in the laboratory by an embryologist, until ready to be transferred to the intended mother’s uterus.

The mother-to-be, or the gestational carrier if you are using one, needs to be ready to receive the embryo(s), and have her uterus prepared accordingly, a step known as endometrial preparation.

For clinics using our vitrified eggs we have a downloadable guide for endometrial preparation on our website.


The endometrium is the name of the tissue lining the inside of the uterus. It is made up of two layers; an inner layer that is attached the wall of the uterus, and an outer, functional layer, which changes in response to a woman’s cycle, and is where an embryo will implant.

The endometrium thickens during the first half of the menstrual cycle or when exposed to estrogen from a developing follicle. During this time, it takes on an appearance known as “trilaminar,” which means that the lining is ready to be developed with progesterone from the release of an egg in ovulation and become receptive for a fertilized egg, now an embryo, to implant and continue its development.

If embryo implantation does not occur, this rich, blood-filled lining will shed, which is the menstrual period.


In an donor egg IVF treatment, the patient will have her uterus “primed” and prepared for the embryo transfer so that the probability of the embryo implanting correctly is increased. This is achieved by administering hormonal medication (estrogen and progesterone), usually orally, or with patches or pessaries. The progress of the endometrial development can be followed by ultrasound.

The embryo transfer should be programmed for when the endometrium is at the best stage for embryo implantation to occur, that is to say when it reaches a thickness of approximately 7 mm and takes on a trilaminar appearance.

Treatment with estrogen and progesterone usually continues after the embryo transfer procedure to help encourage implantation and development, increasing the chances of a successful pregnancy.


One of the important advantage of using frozen donor eggs is that when using eggs from an egg bank, the cycles of the donor and the patient do not need to be synchronized.

In a fresh donor cycle, the donor will undergo ovarian stimulation and when the eggs are mature they will be collected in an egg retrieval procedure. The eggs will be fertilized and the resulting embryos grown in the laboratory until they are ready for transfer or for freezing if to be used in future cycles. While this is happening the patient has to have endometrial preparation to ensure the endometrium is receptive to receive the embryo. As such, the cycles of the donor and the recipient need to be synchronized before the treatment can take place. This is achieved with hormonal medication and can lead to delays in the treatment or a cancelled cycle.

When using frozen eggs, the treatment can take place at the convenience of the intended parent. When they are ready to begin the process they can start the endometrial preparation, and the eggs will be thawed and fertilized in a coordinated fashion, so that the embryo(s) is ready to be transferred at the optimum moment. There is therefore no need for the donor and recipient cycle to be synchronized.

If you would like more information on how to use OvobankID you can read this article: How do egg donation treatments work? The steps for men and women.

You can also register here to access our donor database, or contact us and one of our country specific coordinators will be touch to answer any questions and help guide you through the process.

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