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PubMed · 11299962

Endometrial receptivity: changes in cell-surface morphology.

G Nikas
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Abstract

Ovulation and fertilization trigger embryonic development and endometrial differentiation by corpus luteum progesterone production. These two synchronous processes couple about 1 week later, when the blastocyst begins to implant in the now receptive endometrium (implantation window). Receptivity is a state of endometrial differentiation marked by a change in epithelial morphology: the hairy-like cell microvilli fuse to a single flower-like membrane projection called the "pinopode." Scanning electron microscopy of sequential endometrial biopsies shows that pinopodes form briefly (1-2 days), and their numbers correlate with implantation. On average, the formation of pinopodes is earlier in stimulated (days 19-20) and later in artificial (days 21-22) compared with natural cycles (days 20-21). There is, however, a wide (up to 5 days) variation between women in the cycle days on which pinopodes form. These results suggest the existence of a narrow and discrete implantation window in humans. Detection of pinopodes is a potential clinical marker to assess endometrial receptivity.

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Cell MembraneEmbryo ImplantationEndometriumEpitheliumFemaleHumansMenstrual CycleMicroscopy, Electron, ScanningMicrovilliOvulation InductionPregnancyTime FactorsJournal ArticleReview

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G Nikas. 2000. Endometrial receptivity: changes in cell-surface morphology.. https://doi.org/10.1055/s-2000-12561

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