Frozen embryo transfer can help patients who have extra embryos from fresh IVF cycles
Extra embryos that were achieved through in vitro fertilization, but not selected for fresh intrauterine embryo transfer, can be cryopreserved for future use. These embryos can be replaced after a spontaneous ovulation with appropriate timing in a natural cycle, or they can be transferred at the appropriate time during an artificial cycle.
At the Texas Fertility Center, we most commonly use artificial cycles for FET due to the significant scheduling advantages that this offers our patients. Artificial cycle monitoring involves the administration of estrogen for approximately two weeks in order to allow your uterine lining to develop. Once the uterine lining is at least 7 mm thick, a serum progesterone level is obtained to ensure that spontaneous ovulation has not occurred. At this point, progesterone administration is begun concurrent with estrogen stimulation. At a time by the cell stage at which the embryos were frozen, the embryos are thawed and transferred into the uterus.
The success rate following this procedure ranges from 20 to 30% and depends on the number and quality of embryos that are transferred. The main advantage of frozen embryo transfer is that no ovulation induction medications are used, and there is no need for another oocyte retrieval, along with the associated costs inherent in an IVF cycle. Multiple large studies have demonstrated that there is no increased risk of congenital abnormalities in infants born following the transfer of cryopreserved embryos.