A frozen embryo transfer (FET) is a process to help an individual become pregnant. This procedure uses embryos (fertilized eggs) that have been frozen. During the FET, the embryos are thawed and placed into the uterus. This is done at a time in the patient's menstrual cycle that best supports a pregnancy. The individual will take hormones to help the endometrium (lining of the uterus) accept the embryos. While taking the hormones, blood tests and ultrasound exams are performed to help monitor how the body responds to hormone treatment.