How?

I get all the time, "How can you have a period and have not ovulated?" I thought the same thing at times, and didn't understand it but here is how.

Can you fail to ovulate in your cycle, but still get your period?

Question:

The quick answer is, “ Yes, sort of," but the more biologically correct answer is that you can fail to ovulate, but still have anovulatory bleeding. Technically speaking, a period is the bleeding that occurs about 12 to 16 days after the release of an egg. If no egg is released, it is not really a period that follows, but anovulatory bleeding.

There is a huge difference between cycles in which the woman ovulates but does not get her period, and one in which she gets her period but does not ovulate. What is that difference?

In anovulatory cycles, non-charting women may assume they are menstruating normally, so why would they continue to experience bleeding if ovulation has not occurred? Such bleeding results when estrogen production continues to develop the uterine lining without reaching the threshold necessary to trigger ovulation. In such a case, one of two things may happen, which leads to what appears to be a menstrual period.

Either the estrogen will build up slowly to a point below the threshold and then drop, resulting in "estrogen withdrawal bleeding," or more commonly, the endometrium builds up slowly over an extended period of time, eventually to the point where the resulting uterine lining is so thickened it can no longer sustain itself. This is known as "estrogen breakthrough bleeding." In either case, if you weren't charting, you might think you were simply menstruating, though you would maybe notice a difference in the type of bleeding. Specifically the flow can be either unusually heavy or light and of course, the timing can result in cycle lengths all over the map (or the chart).

I hope this helps answer some questions. It is kind of hard to explain, and to explain to people over and over again. ;)