“Direct laboratory evidence overwhelmingly supports the hypothesis that emergency contraceptives work by mechanisms that do not include post-fertilization events. Since these drugs are administered within hours of intercourse and implantation does not occur until approximately five to seven days after ovulation, use of emergency contraception does not interrupt pregnancy and is ineffective after pregnancy has occurred.”
I am not sure of this source. Who said this?
I hesitated to put the source since it’s copyrighted. PM me if you want to know - their usage agreement says it’s ok to share bits of information with individuals. To borrow from the “about us” page on their website, it’s “written by physicians who are experts in their fields”, “evidence-based”, “unbiased, providing information that is not influenced by commercial interests).” Of course, the data from this article is from other sources - it is not a journal, or source for primary information. They have footnotes for that.
I would not assume anything, but I am saying it seems to be a very possible and normal function of the drug, given that conception may well have already occured by the time Plan B is taken. The web site gives 72 hours (3 full days), but many women are concieving within a day or two, and some within hours of intercourse. If all these women got pregnant (with full implantation), I think Plan B would not be effective.
120 hours is five days. It is fairly rare to ovulate/conceive five full days after intercourse, so **if **Plan B works at all at this stage it would seem to be by some type of interference with implantation.
Plan B has other mechanisms of actions, which I am less familiar with:
Interference with fertilization or tubal transport
Causing regression of the corpus luteum
and lastly - Prevention of implantation by altering endometrial receptivity.
I suppose Plan B’s effect on endometrial receptivity would prevent a feritlized ovum from implanting. The medical definition of pregnancy (for instance, when the pregnancy hormone HCG starts being produced) is after implantation, not fertilization. But I understand that the Catholic Church rejects the medical definition and it is their opinion that pregnancy begins with fertilization.
I will admit here I am talking about probabilities. Perhaps someone will prove, statistically or medically, that Plan B is only preventing ovulation or interfering with the sperm, and never or almost never interferes with an existing embryo. But the heavy burden of proof is on Plan B advocates, since a person’s life starts at fertilization and not at implantation.
Yes, probabilities are at play here. Remember (now this is
not putting the burden of proof on them and you made a good point with that) that effectiveness decreases as time goes on, and also that Plan B is not 100% effective even when taken within 72 hours. So yes, some people probably conceive before they take Plan B - and doesn’t that explain the fact that it is not 100% effective?
It should be noted that the officials for the Catholic Church in the US (USCCB) say, “If, after appropriate testing, there is no evidence that conception has occurred already,** she may be treated with medications that would prevent ovulation, sperm capacitation, or fertilization**. It is not permissible, however, to initiate or to recommend treatments that have as their purpose or direct effect the removal, destruction, or interference with the implantation of a fertilized ovum.”
I assume that the medication they are talking about is Plan B (which is a brand name so they wouldn’t specify that). So apparently they have relieved Plan B from absolutely proving without a doubt that it doesn’t remove destroy or interfere with implantation of the embryo. (Actually, it’s a zygote not an embryo yet.) Plan B most certainly does not remove or destroy a fertilized ovum. But if its other mechanisms of action fail, it may interfere with implantation, which is not a legal or medical definition of abortion, but it is what it is (as the saying goes).