Reproductive outcomes after letrozole stimulated versus artificial frozen-thawed embryo transfer cycles in women with PCOS and/or oligo-anovulation: a systematic review and meta-analysis

作者：Nathalie Søderhamn Bülow, Marie Louise Wissing, Nick Macklon, Anja Pinborg, Kristine Løssl · 发表于：Human Reproduction Update · 年份：2025 · DOI：10.1093/humupd/dmaf011 · 被引用次数：14 · 研究领域：Ovarian function and disorders、Reproductive System and Pregnancy、Gynecological conditions and treatments

BACKGROUND: The global increase in frozen-thawed embryo transfer (FET) cycles has led to a critical evaluation of endometrial preparation methods. While various approaches such as natural or modified natural cycle FET, stimulated FET by use of letrozole (LTZ) and/or gonadotrophins, and artificial cycle (AC) FET, are currently in clinical use, the optimal regimen remains unclear, particularly for women with oligo-anovulation or polycystic ovarian syndrome (PCOS). This systematic review and meta-analysis compares LTZ FET with AC FET regarding reproductive, obstetric, and neonatal outcomes in these populations. OBJECTIVE AND RATIONALE: The aim was to determine whether LTZ FET improves reproductive, obstetric, and neonatal outcomes compared to AC FET in women with ovulatory disorders and/or PCOS. SEARCH METHODS: A comprehensive search of MEDLINE, Cochrane, and ClinicalTrials.gov databases was conducted for studies until June 2024. Eligible studies included women with ovulatory disorders and/or PCOS, comparing LTZ FET to AC FET. Data extraction focused on the live birth rate (LBR), ongoing pregnancy rate, clinical pregnancy rate, pregnancy loss rate, hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), birth weight, small for gestational age (SGA), large for gestational age (LGA), and congenital malformations. OUTCOMES: The search identified 74 studies, and included 15 observational studies and two randomized controlled trials (RCTs) meeting the inclusio...