A Critical Appraisal of Studies on Endometrial Thickness and Embryo Transfer Outcome

Overview

Journal Reprod Biomed Online

Publisher Elsevier

Specialty Reproductive Medicine

Date 2023 Jul 29

PMID 37516058

Authors

Begum Mathyk

Adina Schwartz

Alan Decherney

Baris Ata

Affiliations

Soon will be listed here.

Abstract

A receptive endometrium is required for successful embryo implantation. Endometrial thickness, as measured by ultrasonography, is the most commonly used marker of endometrial receptivity in assisted reproductive technology cycles. Several factors simultaneously affect both endometrial thickness and probability of live birth, including age, oestradiol concentration and oocyte number, among others. Most of the studies investigating a relationship between endometrial thickness and embryo transfer outcomes are retrospective and do not adequately address confounding factors, in addition to other limitations. Despite multiple meta-analyses and studies with large numbers of cycles, controversy still exists. The difference between the results from prospective and retrospective studies is also striking. This article presents a critical appraisal of the studies on endometrial thickness and embryo transfer outcomes in order to highlight methodological issues and how they can be overcome in future studies. Currently available evidence does not seem to support a modification of management just because endometrial thickness is below an arbitrary threshold.

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References

Altman D, Royston P . The cost of dichotomising continuous variables. BMJ. 2006; 332(7549):1080. PMC: 1458573. DOI: 10.1136/bmj.332.7549.1080. View

Kasius A, Smit J, Torrance H, Eijkemans M, Mol B, Opmeer B . Endometrial thickness and pregnancy rates after IVF: a systematic review and meta-analysis. Hum Reprod Update. 2014; 20(4):530-41. DOI: 10.1093/humupd/dmu011. View

Lu Y, Niu Y, Wang Y, He Y, Ding Y, Lu X . Optimal Candidates to Do Fresh Embryo Transfer in Those Using Oral Contraceptive Pretreatment in IVF Cycles. Front Physiol. 2021; 12:576917. PMC: 7991902. DOI: 10.3389/fphys.2021.576917. View

Simeonov M, Sapir O, Lande Y, Ben-Haroush A, Oron G, Shlush E . The entire range of trigger-day endometrial thickness in fresh IVF cycles is independently correlated with live birth rate. Reprod Biomed Online. 2020; 41(2):239-247. DOI: 10.1016/j.rbmo.2020.04.008. View

Hosseini Rashidi B, Sadeghi M, Jafarabadi M, Tehrani Nejad E . Relationships between pregnancy rates following in vitro fertilization or intracytoplasmic sperm injection and endometrial thickness and pattern. Eur J Obstet Gynecol Reprod Biol. 2005; 120(2):179-84. DOI: 10.1016/j.ejogrb.2004.08.016. View

Amir W, Micha B, Ariel H, Liat L, Jehoshua D, Adrian S . Predicting factors for endometrial thickness during treatment with assisted reproductive technology. Fertil Steril. 2007; 87(4):799-804. DOI: 10.1016/j.fertnstert.2006.11.002. View

Gomez-de-Mariscal E, Guerrero V, Sneider A, Jayatilaka H, Phillip J, Wirtz D . Use of the p-values as a size-dependent function to address practical differences when analyzing large datasets. Sci Rep. 2021; 11(1):20942. PMC: 8536742. DOI: 10.1038/s41598-021-00199-5. View

Al-Ghamdi A, Coskun S, Al-Hassan S, Al-Rejjal R, Awartani K . The correlation between endometrial thickness and outcome of in vitro fertilization and embryo transfer (IVF-ET) outcome. Reprod Biol Endocrinol. 2008; 6:37. PMC: 2543019. DOI: 10.1186/1477-7827-6-37. View

Liu K, Hartman M, Hartman A, Luo Z, Mahutte N . The impact of a thin endometrial lining on fresh and frozen-thaw IVF outcomes: an analysis of over 40 000 embryo transfers. Hum Reprod. 2018; 33(10):1883-1888. PMC: 6145412. DOI: 10.1093/humrep/dey281. View

10.

Ata B, Linan A, Kalafat E, Ruiz F, Melado L, Bayram A . Effect of the endometrial thickness on the live birth rate: insights from 959 single euploid frozen embryo transfers without a cutoff for thickness. Fertil Steril. 2023; 120(1):91-98. DOI: 10.1016/j.fertnstert.2023.02.035. View

11.

Sundstrom P . Establishment of a successful pregnancy following in-vitro fertilization with an endometrial thickness of no more than 4 mm. Hum Reprod. 1998; 13(6):1550-2. DOI: 10.1093/humrep/13.6.1550. View

12.

Gingold J, Lee J, Rodriguez-Purata J, Whitehouse M, Sandler B, Grunfeld L . Endometrial pattern, but not endometrial thickness, affects implantation rates in euploid embryo transfers. Fertil Steril. 2015; 104(3):620-8.e5. PMC: 4561002. DOI: 10.1016/j.fertnstert.2015.05.036. View

13.

Oron G, Hiersch L, Rona S, Prag-Rosenberg R, Sapir O, Tuttnauer-Hamburger M . Endometrial thickness of less than 7.5 mm is associated with obstetric complications in fresh IVF cycles: a retrospective cohort study. Reprod Biomed Online. 2018; 37(3):341-348. DOI: 10.1016/j.rbmo.2018.05.013. View

14.

Jimenez P, Schon S, Odem R, Ratts V, Jungheim E . A retrospective cross-sectional study: fresh cycle endometrial thickness is a sensitive predictor of inadequate endometrial thickness in frozen embryo transfer cycles. Reprod Biol Endocrinol. 2013; 11:35. PMC: 3656781. DOI: 10.1186/1477-7827-11-35. View

15.

Hu K, Kawai A, Hunt S, Li W, Li X, Zhang R . Endometrial thickness in the prediction of neonatal adverse outcomes in frozen cycles for singleton pregnancies. Reprod Biomed Online. 2021; 43(3):553-560. DOI: 10.1016/j.rbmo.2021.04.014. View

16.

Momeni M, Rahbar M, Kovanci E . A meta-analysis of the relationship between endometrial thickness and outcome of in vitro fertilization cycles. J Hum Reprod Sci. 2012; 4(3):130-7. PMC: 3276947. DOI: 10.4103/0974-1208.92287. View

17.

Shakerian B, Turkgeldi E, Yildiz S, Keles I, Ata B . Endometrial thickness is not predictive for live birth after embryo transfer, even without a cutoff. Fertil Steril. 2021; 116(1):130-137. DOI: 10.1016/j.fertnstert.2021.02.041. View

18.

Zhang T, Li Z, Ren X, Huang B, Zhu G, Yang W . Endometrial thickness as a predictor of the reproductive outcomes in fresh and frozen embryo transfer cycles: A retrospective cohort study of 1512 IVF cycles with morphologically good-quality blastocyst. Medicine (Baltimore). 2018; 97(4):e9689. PMC: 5794374. DOI: 10.1097/MD.0000000000009689. View

19.

Zhang J, Sun Y, Xu Y, Shi B, Han Y, Luo Z . Effect of Endometrium Thickness on Clinical Outcomes in Luteal Phase Short-Acting GnRH-a Long Protocol and GnRH-Ant Protocol. Front Endocrinol (Lausanne). 2021; 12:578783. PMC: 8165441. DOI: 10.3389/fendo.2021.578783. View

20.

Dogra Y, Singh N, Vanamail P . Autologous platelet-rich plasma optimizes endometrial thickness and pregnancy outcomes in women with refractory thin endometrium of varied aetiology during fresh and frozen-thawed embryo transfer cycles. JBRA Assist Reprod. 2021; 26(1):13-21. PMC: 8769175. DOI: 10.5935/1518-0557.20210037. View