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This program is based on one that was developed in the Diocese of Harrisburg. The method allows couples to identify times of fertility and infertility by recognizing changes that occur during a woman's menstrual cycle. The menstrual cycle consists of a pre-ovulatory phase. The menstrual period (menses) occurs at the beginning of the pre-ovulatory phase. During the pre-ovulatory phase the woman's cycle changes to a fertile phase where sexual intercourse can result in a pregnancy. After ovulation, the woman's body moves to an infertile phase where she can not become pregnant. During various phases of the menstrual cycle, the ovarian hormones estrogen and progesterone, cause recognizable signs and symptoms which make up a woman's internal body language. After menses her mucus and body temperature will change as ovulation approaches and after ovulation occurs. This internal body language is unique to each woman's menstrual cycle. Fertility can be recognized by learning to recognize the signs and symptoms which accompany the event of ovulation.

Mucus Observations

A woman can determine what phase of her cycle she is in by observing her cervical mucus. Careful observations and charting are a vital part of making this method work. Instructors will explain how to observe and chart. Women are asked to observe the color, consistency, change and sensation of her mucus. By understanding these symptoms a woman can determine the approach of ovulation and a time after ovulation has occurred.

Basal Body Temperature

The term basal body temperature (BBT) means a resting temperature, typically after a night's sleep. This temperature will be lower prior to a woman's ovulation and then rise after ovulation. This is caused by her body switching from an estrogen dominant phase of her cycle to a progesterone dominant phase. By charting these temperatures the woman can confirm that ovulation has occurred.


The Philadelphia Archdiocesan program teaches couples to understand this method in two classes, spaced one week apart. This is followed by teacher mentoring for a period of six ovulation cycles.

During the classes, the couples are taught about what to expect when observing the woman's cycle. Various rules are introduced that allow using these observations to achieve or postpone pregnancy.