Posted on Contraceptionblog.com , the official blog of the No Room for Contraception Campaign.
A study published in the journal Fertility and Sterility found that levonorgestrel, the drug contained in Plan B emergency contraception, does inhibit implantation after all, at least some of the time. (Preventing implantation interrupts an existing pregnancy and is an abortive mechanism.)
Despite the fact that the manufacturer lists that the drug may prohibit implantation, advocates of Plan B have argued that the drug does not act in this manner. Many point to the Chilean Institute for Reproductive Medicine studies on rats and monkeys as proof that Plan B doesn't cause abortions.
Others claim that the medical definition of pregnancy begins after implantation and therefore Plan B is not an abortifacient - perpetuating the myth that pregnancy begins at implantation.
The study found that in preventing ovulation, the drug was only 8%-49% effective depending on the amount of delay in using it. When the abortifacient mechanism, as well as other post-fertilizations mechanisms, had an effect, the effectiveness ranged from 16% to 90% in preventing both pregnancy and birth
This isn't good news for Catholic Hospitals that are distributing emergency contraception. And it's not good news for advocates claiming that emergency contraception prevents abortion - when it prohibits implantion, Plan B only changes when, not if, an abortion occurs.
But don't expect this study to make headlines across the nation. And don't expect pro-abortion bloggers to report on it either - facts don't matter when it comes to contraception , unless it helps their cause.
For more information on the controversy over the beginning of pregnancy, visit the pregnancy page.
The abstract can be found at:
http://www.fertstert.org/article/PIIS0015028206047327/abstract
h/t Jivin J for prompting the update
Ruben,
You should be careful about claiming what a study says when it doesn't actually say that. I don't see anything in the abstract of this study which says EC "does inhibit implantation." I see a comment about how the gap of effectiveness "may be explained by overestimation of actual effectiveness and supplementary mechanisms of action, including postfertilization effects" but absolutely nothing which says it does. The gap could be caused solely by the overestimation of actual effectiveness (which Serge discussed here) and increased pre-implantation effects.
You should be especially careful on this because there are studies which have actually studied how EC worked in women's bodies. Read this post at LifeEthics for more information on that.
Serge said:
--------------------------------------------------------
"A study published in the journal Fertility and Sterility found that levonorgestrel, the drug contained in Plan B emergency contraception, does inhibit implantation after all, at least some of the time. (Preventing implantation interrupts an existing pregnancy and is an abortive mechanism.)"
This is absolutely false. In fact, the conclusion of the study from the abstract that you linked to states this:
The gap between effectiveness of levonorgestrel EC estimated from clinical studies and what can be attributed to disruption of ovulation may be explained by overestimation of actual effectiveness and supplementary mechanisms of action, including postfertilization effects.
This study really gives us no new data to even ponder regarding the post-fertilization effects of EC. The effectiveness of EC is now being questioned by pro-EC physicians due to new data. Unfortunately, this is a retrospective study that used old data and modeling.
Anyone who states that this study confirms that LNG acts via a post-fertilization event is simply wrong. In fact, they are not only wrong, but irresponsible.
------------------------
Ruben responds:
Absolutely false?
This study did find support for "supplementary mechanisms of action, including post fertilization effects," Let's explore what two of those effects could be.
1. Inhibition of a new human that is actively trying to implant in the uterine cavity
2. Inhibition of a new human from reaching the uterine cavity in the first place, which in and of itself prohibits implantation in the uterus. This is an ectopic pregnancy, which inevitably will abort the development of the newly created human. (Note, while some studies suggest an increased incidence of ectopic pregnancy associated with LNG, others don't...)
Now, either of these effects results in the abortion of the development of a newly created human. The question seems to be if LNG has either, neither or both mechanisms...
In some ways this is a matter of semantics, as the end result is that implantation in the uterine cavity is may sometime be prevented - and the new life's development and growth aborted.
Irresponsible? Erring on the side of death is irresponsible...
Serge said:
This study did find support for "supplementary mechanisms of action, including post fertilization effects.
No, it did not! Please explain exactly the evidence that this study reports that supports a post-fertilization mechanism of action that could not be explained by an overestimation of actual EC effectiveness. I believe you are misreading the conclusion.
More in this post here(http://lti-blog.blogspot.com/2007/06/bad-reporting-from-our-side-serge.html), and you may be interested in the entire series on Plan B that I have posted (http://lti-blog.blogspot.com/search/label/Emergency%20contraception), including a prediction of these numbers.
------------------------------------
Ruben said:
Serge, I'm aware of your postings on this issue.
Please read the following.
"may be explained by overestimation of actual effectiveness and supplementary mechanisms of action, including postfertilization effects."
Note the "supplementary mechanisms of action, including postfertilization effects" - you seem to be leaving this out of your comments.
It seem that the report does not simply chalk everything up to overestimation...
Serge Said:
====================
Ruben,
Have you read the article, or the recent letter to the editor to the journal Contraception that Mikolajczyk and Stanford wrote? In Contraception 75 (2007) 403, they write "any observed effectiveness over 50% with more than 24 h delay of administration is strong evidence for postfertilization mechanisms of LNG EC, and/or presents a substantial overestimate of the effectiveness of LNG EC [2]. The "[2]" is a footnote referring to the article that you have cited.
They have not presented any data that would support the conclusion that the difference is due to post-fertilization effects. Your claim that their study does so is false, and should be retracted.
--------------------------
Ruben said.
I guess we'll be arguing about "and/or" aspect of this forever...I never claimed that overestimation wasn't a possiblity issue - I don't think anybody on this side of the isle agrees with the claimed efficacy of LNG (Plan B).
The focus was on postfertilization effects.. However, you are arguing against postfertilization alltogether - something the study finds creedence for...otherwise there wouldn't be an "and/or" issue.
Now, it's true, they don't give data on just exactly how often this may possibly happen, so technically you have a point concerning a figure that can be cited
You may notice I did modify the posting after Jivin J challenged me. Unforunately I forgot to modify the following sentence to match the headline change:
"does inhibit implantation after all, at least some of the time. "
It shoud read
"may inhibit implantation after all, at least some of the time. "
All the definitive words should reflect this change, to read "may" or "possibly". At this point I believe updating the post to reflect the changed title is all that is required, not a retraction.
Thanks for the challenge on this, but unless there is something earthshattering that negates the "and/or" aspect of this, I have to move on to other items.
Sorry for the confusion Ruben - Rich Poupard = Serge.
The change of "does" to "may" is reasonable, and makes the post more accurate. Thanks Ruben.
Serge