A frozen embryo transfer, commonly referred to as FET, is the process of using a frozen embryo from a prior IVF cycle.
A frozen embryo transfer cycle or FET, is a much simpler process compared to the egg retrieval cycle. Typically, two to three visits are needed prior to transfer day. A handful of appointments are needed and there is more flexibility in scheduling the monitoring visits.
For women returning for a subsequent pregnancy following delivery, the uterus is re-evaluated prior to beginning the FET cycle.
The frozen embryo transfer may be performed in a programmed cycle or a modified natural cycle depending upon the woman’s menstrual function.
The programmed cycle is widely used by clinics across the United States for a frozen embryo transfer or FET cycle. The woman takes supplemental estrogen, typically by mouth, for about two weeks. The endometrial lining is assessed with a pelvic ultrasound. When the lining looks favorable, progesterone injections are begun and the frozen embryo transfer is scheduled.
The modified natural cycle centers around the woman’s own ovulation. Estrogen supplementation is not used. Ovulation is timed with ultrasound and an ovulation kit. A single dose of hCG is given at the time of the LH surge. Vaginal progesterone is used rather than progesterone injections.