For women who don’t chart, they may have no clue that occasionally they don’t release an egg, assuming that if they are bleeding, they must have periods, right? Wrong. Not all bleeding is created equally. Of course, most of the time, it is due to a true period, but it can also be a symptom of a condition that needs medical attention. And sometimes, it is due to an anovulatory cycle, one in which a drop in hormones causes the uterine lining to shed, but no egg was actually released that cycle.

This is one of the reasons that I stress charting your cervical fluid and temperatures. If you observe only your cervical fluid, you could be misled to believe that you are ovulating when you are not. In other words, your body may make attempts to ovulate by increasing its levels of estrogen in a seemingly consistent pattern, but if the estrogen doesn’t make it over the hormonal threshold, the egg won’t be released. By charting both, you will be able to observe the increase in fertile cervical fluid that indicates approaching ovulation, but if you don’t experience a thermal shift, it could indicate that you have not, in fact, ovulated yet.

A trick to help you identify whether or not you are ovulating is to pay special attention to the concept of the Peak Day, the last day of any slippery, lubricative vaginal sensation, slippery eggwhite cervical fluid, or midcycle spotting. If you do ovulate, the cervical fluid should dry up fairly abruptly, due to the release of progesterone following ovulation.

In situations where your body may be unsuccessfully attempting to ovulate (for example, in long cycles, while breastfeeding, or experiencing PCOS) you would typically observe a pattern of increasingly wet cervical fluid, but instead of fully drying up under the influence of progesterone, it would likely return in sporadic patches, or simply remain somewhat wet. Knowing how to accurately determine your Peak Day is critical if you are to correctly follow the rules for both birth control and pregnancy achievement.