From the medical point of view, the recipient has to get her body ready to receive the embryo that has been created using donor eggs in order to maximize the chances of implantation.
If fresh donor eggs are used, then synchronization between the cycles of the donor and the recipient is required. Inversely, this step is not needed when frozen donor eggs are used.
The recipient has to prepare her body for donor-egg IVF by means of endometrial preparation, which makes the uterus to grow its lining so that it is prepared for the embryo to implant successfully after the transfer (ET). To this end, the patient has to follow a strict drug protocol.