There are multiple methods of Natural Family Planning. Each NFP method is focused on one or more signs of female fertility. They can be grouped into three categories:

The Cervical Mucus Methods (CMM)
These methods use the careful observation and charting of a woman’s daily cervical mucus as the primary biological marker to determine days of fertility and infertility. CMMs are also commonly called "Ovulation Methods" (OM). There are a number of methods that use this approach to NFP:

• Creighton Model FertilityCare System – www.creightonmodel.com
• FEMM Health – www.femmhealth.org
• Billings Ovulation Method – www.billings.life
• Family of America’s Foundation Method – www.familyplanning.net

Sympto-Thermal Methods (STM) 
These methods rely on the careful observation and daily charting of multiple fertility signs and cross-checking two or more of the signs to pinpoint ovulation. The biological markers used to determine days of fertility and infertility include cervical mucus, Basal Body Temperature (BBT), and cervical changes. The methods that utilize this approach include:

• SymptoPro Fertility Education – www.symptopro.org
• Couple-to-Couple League – www.ccli.org

Sympto-Hormonal Methods (SHM) 
These methods rely on the observation and daily charting of cervical mucus with the addition of also using an at-home electronic fertility monitor or ovulation predictor kit to measure a woman’s reproductive hormone levels. The primary method using this approach is:

• Marquette Model – www.marquette.edu/nursing/natural-family-planning-model.php

• http://usccb.org/issues-and-action/marriage-and-family/natural-family-planning/what-is-nfp/methods.cfm