Natural family planning (NFP)
is a term referring to the family planning methods approved by the Roman Catholic Church. In accordance with the Church's requirements for sexual behavior in keeping with its philosophy of the dignity of the human person, NFP excludes the use of other methods of birth control.
Periodic abstinence and the natural infertility caused by breastfeeding are the only methods deemed moral by the Church for avoiding pregnancy. When used to avoid pregnancy, NFP limits sexual intercourse to naturally infertile periods; portions of the menstrual cycle, during pregnancy, and after menopause. Various methods may be used to identify whether a woman is likely to be fertile; this information may be used in attempts to either avoid or achieve pregnancy.
Possibly the earliest Christian writing about periodic abstinence was by St. Augustine. In the year 388, he wrote, "Is it not you who used to counsel us to observe as much as possible the time when a woman, after her purification, is most likely to conceive, and to abstain from cohabitation at that time...?" The Manichaeans (the group the early church father St. Augustine wrote of) believed that it was immoral to create any children, thus (by their belief system), trapping souls in mortal bodies. Augustine condemned them for their use of periodic abstinence: "From this it follows that you consider marriage is not to procreate children, but to satiate lust.
There are three main types of NFP: the symptoms-based methods, the calendar-based methods, and the breastfeeding or lactational amenorrhea method. Symptoms-based methods rely on biological signs of fertility, while calendar-based methods estimate the likelihood of fertility based on the length of past menstrual cycles. According to the Couple to Couple League, "the fact that some methods of NFP can be 99% effective in the avoidance of pregnancy seems unknown to most of the general...