Bourgain Claire, Devroey Paul
Department of Pathology, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium.
Hum Reprod Update. 2003 Nov-Dec;9(6):515-22. doi: 10.1093/humupd/dmg045.
Ovarian stimulation for IVF is known to affect luteal phase function. The endometrium in IVF cycles is thus subject to an altered endocrinological environment and to a possible direct effect of the ovarian stimulation therapy. Factors influencing the endometrial receptivity in such cycles are poorly understood. Studies comparing the endometrium in IVF cycles with natural cycles as controls have shown premature secretory changes in the post-ovulatory and early luteal phase of IVF cycles, followed by a large proportion of dyssynchronous glandular and stromal differentiation in the mid-luteal phase. These findings suggest a profound modification of luteal endometrial development in stimulated cycles. This hypothesis is further supported by the demonstration of a modified endometrial steroid receptor regulation and a profound antiproliferative effect in IVF cycles. The time of maximal endometrial receptivity is defined as the implantation window and is characterized by the expression of various endometrial products, among which pinopodes, integrins and leukaemia inhibitory factor are best described. Premature expression of pinopodes and integrins are in line with the observation of precocious luteal transformation following ovarian stimulation, although the clinical relevance with respect to the establishment of a clinical pregnancy awaits further validation. Studies exploring the endometrium within the cycle of embryo transfer have shown a deleterious effect of severe peri-ovulatory maturation advancement exceeding 3 days, as no clinical pregnancies were obtained in this condition. Further unravelling of molecules involved in the implantation mechanism is needed for a better comprehension of the link between altered endometrial development and receptivity in IVF cycles.
已知用于体外受精（IVF）的卵巢刺激会影响黄体期功能。因此，IVF周期中的子宫内膜会受到内分泌环境改变以及卵巢刺激疗法可能产生的直接影响。目前对影响此类周期中子宫内膜容受性的因素了解甚少。将IVF周期的子宫内膜与自然周期作为对照进行比较的研究表明，IVF周期在排卵后和黄体早期会出现过早的分泌期变化，随后在黄体中期有很大比例的腺体和间质分化不同步。这些发现表明，在刺激周期中黄体期子宫内膜发育发生了深刻改变。子宫内膜类固醇受体调节的改变以及IVF周期中显著的抗增殖作用进一步支持了这一假说。子宫内膜最大容受性的时间被定义为着床窗，其特征是各种子宫内膜产物的表达，其中微绒毛、整合素和白血病抑制因子的描述最为详尽。微绒毛和整合素的过早表达与卵巢刺激后黄体过早转化的观察结果一致，尽管其与临床妊娠建立的临床相关性尚待进一步验证。探索胚胎移植周期内子宫内膜的研究表明，排卵周围成熟提前超过3天会产生有害影响，因为在这种情况下未获得临床妊娠。为了更好地理解IVF周期中子宫内膜发育改变与容受性之间的联系，需要进一步阐明参与着床机制的分子。
