OBJECTIVE To measure free and total 25-hydroxyvitamin D [25(OH)D] immediately before embryo transfer and analyze its association with early pregnancy outcome parameters such as biochemical pregnancy, implantation rate, and clinical pregnancy rates in women undergoing fresh embryo transfer after their first ovarian hyperstimulation. DESIGN Prospective cohort study. SETTING Academically affiliated private fertility center. PATIENT(S) A total of 2,569 women undergoing fresh embryo transfer after ovarian hyperstimulation. INTERVENTIONS(S) None. MAIN OUTCOME MEASURE(S) The study end points were biochemical pregnancy rate, implantation rate, clinical pregnancy rate, ectopic pregnancy rate, early miscarriages, and ongoing pregnancy rate. Free and total 25(OH)D concentrations were measured 1 day before embryo transfer. RESULT(S) Total 25(OH)D correlated with free 25(OH)D. Total and free 25(OH)D serum concentrations were similar in those patients reaching and not reaching the study outcomes (biochemical pregnancy rate, implantation rate, clinical pregnancy rate, ectopic pregnancy rate, early miscarriages, and ongoing pregnancy rate). There was likewise no statistical difference when analyzing the frequency of all study outcomes in quintiles of either total or free 25(OH)D. In addition, the study population was divided into three groups according to the total vitamin D status based on clinical practice guideline. All outcomes were similar in women with adequate, insufficient, and deficient total 25(OH)D. Multiple linear regression analysis considering confounding likewise indicated no association of free or total vitamin D with any of the study outcomes. CONCLUSION(S) Neither free nor total 25(OH)D concentration at embryo transfer was associated with successful embryo implantation in women undergoing fresh transfer after ovarian hyperstimulation.

中文翻译：

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维生素 D 对人类胚胎植入的影响——一项针对接受新鲜胚胎移植的女性的前瞻性队列研究

目的 在胚胎移植前立即测量游离和总 25-羟基维生素 D [25 (OH) D] 并分析其与早期妊娠结局参数（如生化妊娠、着床率和临床妊娠率）的相关性。第一次卵巢过度刺激。设计前瞻性队列研究。设置 学术附属私人生育中心。患者 (S) 共有 2,569 名女性在卵巢过​​度刺激后接受新鲜胚胎移植。干预 (S) 无。主要观察指标（S） 研究终点为生化妊娠率、着床率、临床妊娠率、异位妊娠率、早期流产率和持续妊娠率。在胚胎移植前 1 天测量游离和总 25 (OH) D 浓度。结果 (S) 总 25 (OH) D 与游离 25 (OH) D 相关。达到和未达到研究结果（生化妊娠率、着床率、临床妊娠率、异位妊娠率、早期流产和持续妊娠率）的患者的总和游离 25 (OH) D 血清浓度相似。在分析总 25 (OH) D 或游离 25 (OH) D 的五分位数中所有研究结果的频率时，同样没有统计学差异。此外，根据临床实践指南，根据总维生素 D 状态将研究人群分为三组。在总 25 (OH) D 充足、不足和不足的女性中，所有结果相似。考虑混杂因素的多元线性回归分析同样表明游离或总维生素 D 与任何研究结果无关。