Association of embryo transfer type with infertility in endometriosis: a systematic review and meta-analysis

Purpose The study aims to evaluate whether frozen embryo transfer can restore optimal receptivity leading to better assisted reproductive technology outcomes in women with endometriosis.

This systematic review and meta-analysis, conducted from January 10, 2021 to July 1, 2021, searched the Cochrane Library, PubMed, Embase, Web of Science, OVID, and Clinicaltrials.gov databases from inception to January 10, 2021. The search strategy combined search terms as follows: (“endometriosis” OR “deep endometriosis” OR “endometrioma”) AND (“frozen-thawed embryo transfer” OR “frozen embryo transfer” OR “freeze-all strategy”) AND (“pregnancy outcome” OR “live birth rate” OR “clinical pregnancy rate” OR “miscarriage rate”). No publication time or language limits were set during the searches. In addition, references of the related articles were searched by hand. Patients were included if they had a history of endometriosis and had received fresh or frozen embryo transfer. Only the first transfer cycle was included. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to express outcomes, and data synthesis was conducted using RevMan, version 5.4 software.

A total of six studies with moderate methodologic quality were retrieved in the meta-analysis. The studies included 3010 women with endometriosis who wanted to conceive; 1777 (59.0%) had frozen embryo transfer, and 1233 (41.0%) had fresh embryo transfer. There was a significantly higher frequency of live births in the frozen embryo group than in the fresh embryo group (OR, 1.53; 95% CI, 1.13–2.08; P = .007). Despite a similar clinical pregnancy rate in the two groups (OR, 1.26; 95% CI, 0.95–1.69; P = .11), the difference in miscarriage rate was significant (OR, 0.70; 95% CI, 0.50–0.97; P = .03). Evidence quality was considered moderate.

Cryopreserved embryo transfer has resulted in preferable reproduction outcomes when compared with fresh embryo transfer in patients with endometriosis, but the evidence is not yet abundant. More strictly designed research is needed to evaluate whether frozen embryo transfer leads to better reproductive outcomes in women with endometriosis compared with those receiving fresh embryo transfer. Registration number PROSPERO CRD42021248313. Similar content being viewed by others

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We thank the authors of the retrieved studies for their research contributions to the field of reproductive fertility in the setting of endometriosis. We thank BioMed Proofreading® LLC for their copyediting services. Author information Authors and Affiliations Contributions H.D.: conception and design, data collection, analytic strategy, manuscript revision, and final article approval. Y.C.: conception and design, search and collection of data, analysis and synthesis, writing, and final article approval. M.S.: search and collection of data, analysis, manuscript revision, and final article approval. S.W.: collection of data, manuscript revision, and final article approval. X.L.: conception and design, manuscript revision, and final approval. Corresponding author Ethics declarations Competing interests The authors declare no competing interests. Additional information Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Rights and permissions About this article Cite this article Chang, Y., Shen, M., Wang, S. et al. Association of embryo transfer type with infertility in endometriosis: a systematic review and meta-analysis. J Assist Reprod Genet 39, 1033–1043 (2022). https://doi.org/10.1007/s10815-022-02460-w Received: Accepted: Published: Version of record: Issue date: DOI: https://doi.org/10.1007/s10815-022-02460-w