[TheBattman]

In addition, this study does not support an anti-implantation contraceptive effect of LNG in EC; however, additional targets, besides those described herein, should also be considered and further investigated for the contraceptive effects of LNG.

That's kind of like saying that running an OBDII test on my Chevrolet Tahoe did not support a non-stopping effect of new brakes...

The test had no way of testing actual implantation. IN fact - when reading the entire test, we find that the test only really addressed chemical and hormonal effects, as well as limited testing of any changes (or lack thereof) to some tissues.

Nothing in the test was designed to disclude the possibility that this drug (basically a super dose of birth control pills) prevents implantation. It is all conjecture.

Just check the literature with Plan B - it specifies that it "may prevent the implantation of fertilized ovum".

So the study doesn's support nor dis-prove that method.

[hocndoc]

As I have said before, I'm still not encouraging the use of this protocol because of the questions about implantation and I do not believe that Plan B should be OTC. This study is about as close as possible in humans to test the effects of a protocol on ovulatory women without risking actual embryos.

These results also correlate with the presence of normal histopathological features in endometrial biopsies taken during the implantation window in women from Groups B, C, and D. Indeed, in this study, the process of transformation of endometrium into decidua, as a consequence of endometrial cell differentiation independently of conception occurred normally in women receiving LNG at the time or after the occurrence of LH surge. In this regard, the existence of edematous changes along with development of prominent spiral arteries in LNG-exposed tissues strongly suggest the apparent preservation of endometrial structures thought to be associated with implantation capabilities [45,46]. A successful implantation requires an adequate synchronization between embryo and endometrium development for invasion of spiral arteries by trophoblast cells [47]. These results suggest that postovulatory contraceptive efficacy of LNG may not involve alterations in the mechanisms associated with endometrial receptivity. A similar conclusion was reached by Raymond et al. [48], where no substantial evidence for the contraceptive effect of the Yuzpe regimen at the level of endometrium could be established.

Studies in Cebus monkeys and rats have shown no interference in implantation of embryos.

In actual human usage, the pills are only effective about 70%-80% of the time, meaning that about 20% to 30% of the time, women do get pregnant.