Frozen Embryo Transfer (FET)

If you have extra embryos or had a freeze-all cycle, the next step is a frozen embryo transfer (FET). Luckily, the process of FET is much easier than the IVF cycle itself. There are a natural FET and a medicated FET cycle.

Natural FET

A natural FET follows the body’s natural ovulation and is best for those with regular cycles and predictable ovulation. Once ovulation occurs, transfer can take place 3-5 days later, depending on the frozen embryo stage. Many clinics do not go this route, however, due to the requirement of frequent ovulation monitoring and the possibility of cancellation due to low estrogen or progesterone levels.

Medicated FET

On day 3 of the cycle, the woman will go in for a baseline ultrasound. From then, oral pills, suppositories or shots of estrogen and progesterone will be taken to prepare the uterus and its lining. Additionally, ovulation inducing medication may be used to time ovulation perfectly.

Once ovulation occurs, the transfer will be 3-5 days after, depending on the embryo. There are far fewer visits to the clinic during a medicated FET which makes it a go-to choice for many clinics.[1]

Effectiveness of FETs

Recent and multiple studies have shown that FETs have an even higher clinic pregnancy rate than fresh IVF cycles.[2][3][4] This may be due to the reduced risk of ovarian hyperstimulation syndrome (OHSS) and improved outcomes for the mother.[5]

Additionally, thawed embryos have a 85% or higher surviving thaw rate after cryopreservation.[6]

Talk to your doctor about FET protocols and see what’s right for you.

[1] “73. What Is the Difference Between a Natural-Cycle Frozen Embryo Transfer (FET) and a Medicated FET?” n.d. Dominion Fertility . Accessed May 1, 2018. https://www.dominionfertility.com/fertility-treatment-faq/73-what-is-the-difference-between-a-natural-cycle-frozen-embryo-transfer-fet-and-a-medicated-fet/.

[2] Shapiro, Bruce S, Said T Daneshmand, Forest C Garner, Martha Aguirre, Cynthia Hudson, and Shyni Thomas. 2011. “Evidence of Impaired Endometrial Receptivity after Ovarian Stimulation for in Vitro Fertilization: A Prospective Randomized Trial Comparing Fresh and Frozen-Thawed Embryo Transfer in Normal Responders.” Fertility and Sterility 96 (2). Elsevier: 344–48. https://doi.org/10.1016/j.fertnstert.2011.05.050.

[3] Roque, Matheus, Karinna Lattes, Sandra Serra, Ivan Solà, Selmo Geber, Ramón Carreras, and Miguel Angel Checa. 2013. “Fresh Embryo Transfer versus Frozen Embryo Transfer in in Vitro Fertilization Cycles: A Systematic Review and Meta-Analysis.” Fertility and Sterility 99 (1). Elsevier: 156–62. https://doi.org/10.1016/j.fertnstert.2012.09.003.

[4] Roque, Matheus, Marcello Valle, Fernando Guimarães, Marcos Sampaio, and Selmo Geber. 2015. “Freeze-All Policy: Fresh vs. Frozen-Thawed Embryo Transfer.” Fertility and Sterility 103 (5). Elsevier: 1190–93. https://doi.org/10.1016/j.fertnstert.2015.01.045.

[5] Evans, Jemma, Natalie J. Hannan, Tracey A. Edgell, Beverley J. Vollenhoven, Peter J. Lutjen, Tiki Osianlis, Lois A. Salamonsen, and Luk J.F. Rombauts. 2014. “Fresh versus Frozen Embryo Transfer: Backing Clinical Decisions with Scientific and Clinical Evidence.” Human Reproduction Update 20 (6). Oxford University Press: 808–21. https://doi.org/10.1093/humupd/dmu027.

[6] Pavone, Mary Ellen, Joy Innes, Jennifer Hirshfeld-Cytron, Ralph Kazer, and John Zhang. 2011. “Comparing Thaw Survival, Implantation and Live Birth Rates from Cryopreserved Zygotes, Embryos and Blastocysts.” Journal of Human Reproductive Sciences 4 (1). Wolters Kluwer -- Medknow Publications: 23–28. https://doi.org/10.4103/0974-1208.82356.