a little theory

[weasel]

ok, so from my understanding the morning after pill will just delay ovulation by a day, if it hasn't happened, not since an egg has to be fertilized if the fallopian tube couldn't delaying it actually cause pregnancy in certain cases. the way I figure it is that if the egg meets the sperm too late then it wont attach itself to the uterus and will just be passed out and since it takes time for the sperm to travel then one day might actually cause this to happen, and if I am mistaken about this then please let me know

[Pill]

I was under the impression that the morning after pill prevented implantation of a zygote into the uterine wall. I'd have to look it up and double-check, though.

[edit]
After reading around some, I see that the current thinking is indeed that prevention of ovulation is the primary mechanism by which EC pills prevent pregnancy.


Your theory relies upon two points: That ECPs will only delay ovulation for a day, and that an ovum released post-coitus could travel all the way down the fallopian tube before sperm from that same coital act could reach it.

The first is hypothetically possible, and probably depends on the specific ECP used, but I am fairly sure that the second is false, so I do not think that under those circumstances ECPs could cause a pregnancy that would not otherwise happen.

Of course, I could be wrong; I'd sooner hear it from someone who knows more.

[Brandye]

The "Morning After Pill" is a term applied to three different forms of emergency contraception.

1. Today, the most common is what is named Plan B. This is available (in some countries) in two forms: a one dose variety and a two dose variety. It is essentially a higher concentration birth control pill. The sooner taken after unprotected sex, the more effective. Some countries state effectiveness up to one week; most, up to three days.

2. For many years doctors, and women, used standard birth control pills for this purpose. Each brand and type of pill has differing numbers of pills and number of doses to be effective. One must know what she is doing to use this approach. The effectiveness is the same as above for Plan B. I have prepared packets of pills approved for this use in my medical bag.

Each of these works in one of three ways:
a. If ovulation has not occurred, it will prevent/delay ovulation for various lengths of time.
b. If ovulation has occurred, it will help to prevent fertilization of the egg. An additional "shell" is formed.
c. If a fertilized egg is present in the tubes, it will make implantation in the uterine wall difficult.

If pregnancy is established (implantation has occurred), it will have no effect.

3. Mifepristone (RU-486) is the true "abortion pill." This must be administered by medical personnel and, in most cases, will be four doses. Actually, two doses each of two different drugs over a few days. It will not be administered until after one or more periods have been missed and pregnancy has been established. It causes spontaneous abortion and is used up to three months after conception.

Each of the three approaches will cause some discomfort (mife, the most) and most women who use these approaches are not eager to repeat the experience.

Both of you are partly correct but the devil (and effectiveness) is in the details. Read various stickies under Sexual Health: Woman and find out how hormones affect the body. And, in the meantime, do not add to the various myths that are floating around about how these things work.