Mifepristone, but not levonorgestrel, inhibits human blastocyst attachment to an in vitro endometrial three-dimensional cell culture model.

BACKGROUND: The use of fertility regulating drugs is limited among various socio-ethnic groups due to limited knowledge about their mechanism of action. This study investigates the effect of levonorgestrel and mifepristone on attachment of human embryos to an in vitro endometrial construct. METHOD: Three-dimensional endometrial constructs were established by co-culturing early luteal phase human endometrial stromal and epithelial cells. Expression of endometrial receptivity markers in this construct were examined by immunohistochemistry. Effects of mifepristone and levonorgestrel on viability and attachment of human blastocysts were investigated. RESULTS: Endometrial constructs expressed the factors involved in endometrial receptivity: estrogen receptor, progesterone receptor, vascular endothelial growth factor, leukemia inhibitory factor, interleukin-1, COX-2, MUC-1 and integrin-alpha(V)beta(3). None of the 15 embryos cultured with mifepristone attached to the endometrial construct (P < 0.01), whereas 10/17 in control, and 6/14 in levonorgestrel, groups attached. The attachment was confirmed by the positive expression of cytokeratin 7 at the attachment site. CONCLUSION: Mifepristone inhibits blastocyst attachment. Levonorgestrel did not impair the attachment of human embryos to the in vitro endometrial construct. This model could be used to understand endometrial receptivity and embryo-endometrial dialog and to develop new fertility regulating substances.

Mid-trimester induced abortion: a review.

Mid-trimester abortion constitutes 10-15% of all induced abortion. The aim of this article is to provide a review of the current literature of mid-trimester methods of abortion with respect to efficacy, side effects and acceptability. There have been continuing efforts to improve the abortion technology in terms of effectiveness, technical ease of performance, acceptability and reduction of side effects and complications. During the last decade, medical methods for mid-trimester induced abortion have shown a considerable development and have become safe and more accessible. The combination of mifepristone and misoprostol is now an established and highly effective method for termination of pregnancy (TOP). Advantages and disadvantages of medical versus surgical methods are discussed. Randomized studies are lacking, and more studies on pain treatment and the safety of any method used in patients with a previous uterine scar are debated, and data are scarce. Pain management in abortion requires special attention. This review highlights the need for randomized studies to set guidelines for mid-trimester abortion methods in terms of safety and acceptability as well as for better analgesic regimens.