Questions About Morning After Pill

Hello,
I am the Nurse Manager at a California Pregnancy Counseling Center and I used to be a FertilityCare Practitioner with the Creighton Model. I believe I have contacted you before regarding other topics (like abortion pill reversals or contraception information, etc.) but since these questions will sound very suspicious, I thought I should mention these things ahead of time, since I am trying to give our clients as much truthful information about the medications as possible.

First, I know that the morning after pills (Plan B) are just large doses of synthetic progesterone I’ve read they are anywhere from 4-40 times the dose in a regular birth control pill.) My question is: if a woman has just ovulated, will this large dose of progesterone really have any negative effect on the lining of the uterus? As I recall from the Creighton Model, some women are given progesterone supplements (bioidentical, usually) in their post-peak phase if they’re at high risk for miscarriage, and they are given the progesterone supplements throughout their first trimester if necessary. So is the morning after pill really an abortifacient? It seems to me that the extra progesterone (although it might be unnecessary) would just ensure the lining of the uterus is in place if conception has occurred but implantation has not yet occurred. I also know the morning after pill doesn’t work well to prevent pregnancy — perhaps it doesn’t really work at all, since most women have no idea where they are in their cycle and wouldn’t know if they’re fertile or not. I can’t tell you how many women I’ve had at the clinic who’ve said they took the morning after pill and they still got pregnant!

My second question is along the same line of thinking: the abortion pill RU-486 is a progesterone receptor blocker, right? So if a woman regrets taking the RU-486 and wants to reverse it (assuming she has not taken the Cytotec yet,) could she theoretically take the morning after pill to have the synthetic progesterone compete for the receptors that the RU-486 blocks? (Not that I would EVER suggest or advocate something like that! Both drugs have so many other horrible side effects, and abortion pill reversal needs to be done under a doctor’s supervision, plus the woman would need to be checked to see if the baby is still viable.)

Thank you so much for your time in considering these questions.