A: A sensation or feeling of dryness around the genital area. The number of such days may vary in each cycle. They may be many in a long cycle, but few, if any, in a short cycle. (BIP).

Aa: Continuous unchanging discharge (BIP).

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B: The end of the dry sensation means that the mucus has begun. If no dry days occur following menstruation, the mucus has already begun.
A change from the continuous unchanging discharge (BIP) to "something else" marks possible fertility.

C: Development of mucus (no fixed number of days). The mucus prolongs the life of the sperm cells. Conception may occur from any genital contact on mucus days prior to ovulation and for three days past the PEAK.

D: At the highest point of fertility the mucus gives a definite lubricative sensation. The last day of this sensation is marked as the PEAK. This point is very close to the time of ovulation. Clear strings of mucus may be seen one or two days before the PEAK but disappear leaving the slippery sensation. The vulva is swollen.

E: There is no wetness or slipperiness after the PEAK. On the day following the PEAK the mucus becomes cloudy and sticky or disappears altogether leaving a dry sensation at the vulva. Days 2 and 3 will also have cloudy and sticky mucus or be dry. Conception may occur from any genital contact on these three days after the PEAK.

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F: The length of time between the PEAK of the mucus and the onset of the next menstruation is about two weeks. Infertility begins again from the fourth day after the PEAK. If any mucus occurs from then on it will usually be sticky and opaque. The egg is dead. Just before menstruation the mucus may become wet.

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