Fuzz, if that was true (and I know it's said to be true) the emergency contraception pill would have a much higher failure rate.
True, it will prevent ovulation, but if you ARE pregnant it irritates the lining of the uterus enough to preven implantation.
And a good percentage of the time a woman having sex that has to worry about being pregnant will already have released an egg. It's how the female body works. A female's natural desire for sex is strongest when the egg is released, usually about a few days after a menstrual cycle.
http://www.ovulation-calendar.com/ovula ... q.html#a02
"Ovulation usually takes place 14 days after the beginning of your menstrual cycle. The time of ovulation within the menstrual cycle is determined by the luteal phase, which is usually 12 to 16 days long."
"Your fertile period starts about 4-5 days before ovulation, and ends about 24-48 hours after it. This is because sperm can live in your body for approximately 4 to 5 days, and the egg can live for 24 to 48 hours after being released."
So...unless you time sex to occur only withing a few days after your menstrual cycle, and most women don't because after your true cycle you may still show blood for another day or two because of the time is takes to get out of your body and most women still think they're having it, and then wait until a week before you start again, good chances are that the emergency pill works as an early abortive pill for you.
It does nothing to stop the fertilization of an already released egg, simply makes it not able to implant.
Chrys