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Fertil Steril. 2001 Nov;76(5):962-8.

Increasing levels of estradiol are deleterious to embryonic implantation because they directly affect the embryo.

Author information

1
Instituto Valenciano de Infertilidad Foundation (FIVIER), Valencia, Spain.

Abstract

OBJECTIVE:

To investigate whether the deleterious effect of E(2) on embryonic implantation is due to a direct effect on the endometrium, on the embryo, or both.

DESIGN:

Prospective, controlled in vitro study.

SETTING:

Tertiary infertility center.

PATIENT(S):

Fertile patients in the luteal phase with histologically normal endometrium who were attending the infertility clinic as oocyte donors (n = 14).

INTERVENTION(S):

E(2) dose-response (0, 10(-8), 10(-7), 10(-6), 10(-5), and 10(-4) M) and time course (day 2 vs. day 5) experiments were performed in an in vitro embryo adhesion assay composed of human polarized endometrial epithelial cells obtained from fertile patients and mouse embryos.

MAIN OUTCOME MEASURE(S):

Blastocyst formation rate and embryo adhesion rate.

RESULTS:

Monolayers of polarized endometrial epithelial cells expressed ERalpha at the mRNA level. The E(2) dose response of blastocysts with polarized endometrial epithelial cells (n = 235) demonstrated a progressive reduction in embryonic adhesion that was statistically significant at 10(-6) M. When polarized endometrial epithelial cells were treated alone with increasing doses of E(2) for 3 days and E(2) was then removed and blastocysts added (n = 410), embryonic adhesion was not significantly reduced, except at 10(-4) M. When 2-day mouse embryos (n = 609) were treated with increasing E(2) concentrations until day 5, the rate of blastocyst formation significantly decreased at a concentration >or= 10(-6) M, and embryonic adhesion decreased when blastocysts (n = 400) were obtained at a concentration >or= 10(-7) M. Time course experiments of embryos cultured for 2 days with polarized endometrial epithelial cells (n = 426) showed that the adhesion rate was higher at E(2) levels of 10(-7), 10(-6) and 10(-5) M compared with embryos cultured for 5 days (n = 495).

CONCLUSION(S):

High E(2) levels are deleterious to embryo adhesion in vitro, mainly because they have a direct toxic effect on the embryo that may occur at the cleavage stage.

Comment in

PMID:
11704118
DOI:
10.1016/s0015-0282(01)02018-0
[Indexed for MEDLINE]

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