Endometrial Preparation in Frozen Embryo Transfer Cycles

Summary

In order to get optimal pregnancy rates after frozen embryo transfer (FET), the embryo stage and endometrium should be synchronized. Endometrial preparation is done by either natural, artificial (Hormonal replacement therapy HRT) , modified natural methods or mild ovarian stimulation. HRT cycle has a better schedualization however, there are some reports about higher rates of miscarriage, pregnancy induced hypertension (PIH) and preeclampsia (PET) in HRT cycles. A recent study has found that incorporation of the aromatase inhibitor (letrozole) to HRT cycles was associated with better FET outcomes in comparison to hormonal replacement therapy cycles alone. Meanwhile, mild ovarian stimulation protocol can be done either by oral drugs like letrozole or by letrozole plus gonadotropins . So this study aims to compare the reproductive outcomes in two endometrial preparation protocols for frozen embryo transfer cycles; letrozole mild ovarian stimulation versus HRT plus letrozole incorporation.

Timeline

Start

2024-02-24

Primary completion

2024-11-25

Completion

2024-12-25

Publications

• Background Elgindy EA, Abdelghany AA, Sibai AbdAlsalam H, Mostafa MI. The novel incorporation of aromatase inhibitor in hormonal replacement therapy cycles: a randomized controlled trial. Reprod Biomed Online. 2022 Apr;44(4):641-649. doi: 10.1016/j.rbmo.2021.10.025. Epub 2021 Dec 20.
• Background Ezoe K, Fukuda J, Takeshima K, Shinohara K, Kato K. Letrozole-induced endometrial preparation improved the pregnancy outcomes after frozen blastocyst transfer compared to the natural cycle: a retrospective cohort study. BMC Pregnancy Childbirth. 2022 Nov 7;22(1):824. doi: 10.1186/s12884-022-05174-0.
• Background An BGL, Chapman M, Tilia L, Venetis C. Is there an optimal window of time for transferring single frozen-thawed euploid blastocysts? A cohort study of 1170 embryo transfers. Hum Reprod. 2022 Nov 24;37(12):2797-2807. doi: 10.1093/humrep/deac227.
• Background Mumusoglu S, Polat M, Ozbek IY, Bozdag G, Papanikolaou EG, Esteves SC, Humaidan P, Yarali H. Preparation of the Endometrium for Frozen Embryo Transfer: A Systematic Review. Front Endocrinol (Lausanne). 2021 Jul 9;12:688237. doi: 10.3389/fendo.2021.688237. eCollection 2021.
• Background Zhang J, Liu H, Wang Y, Mao X, Chen Q, Fan Y, Xiao Y, Kuang Y. Letrozole use during frozen embryo transfer cycles in women with polycystic ovary syndrome. Fertil Steril. 2019 Aug;112(2):371-377. doi: 10.1016/j.fertnstert.2019.04.014. Epub 2019 May 21.
• Background Godiwala P, Makhijani R, Bartolucci A, Grow D, Nulsen J, Benadiva C, Grady J, Engmann L. Pregnancy outcomes after frozen-thawed embryo transfer using letrozole ovulation induction, natural, or programmed cycles. Fertil Steril. 2022 Oct;118(4):690-698. doi: 10.1016/j.fertnstert.2022.06.013. Epub 2022 Jul 19.
• Background Lawrenz B, Melado L, Fatemi HM. Frozen embryo transfers in a natural cycle: how to do it right. Curr Opin Obstet Gynecol. 2023 Jun 1;35(3):224-229. doi: 10.1097/GCO.0000000000000862. Epub 2023 Mar 14.

Drugs

Indications

No indication recorded.