[Brandye]

Wonderful question, demon. Our bodies continue to produce oestrogen and progesterone; the added (synthetic) hormones from the oral contraceptives are just strong enough to keep the body confused, prevent ovulation and keep a thick mucous plug in the cervical os. The more important question is, "Is it more risky to miss a pill on the fifteenth day of your cycle than on, say, the twenty-second day." I cannot find a definitive answer to that and it would depend upon the natural cycles of hormones.

I shall make a few calls. In the meantime, you are correct; no ovulation, no fertile period. And the surprise to your body of having the hormone level in the bloodstream drop below therapeutic level could shock one into ovulation any day.

I'll get back; hopefully with a better answer.