Ovulation Models


The Billings Ovulation Model

The Billings Ovulation Method, a modern and scientifically sound method of Natural Family Planning was developed by Drs. John and Evelyn Billings of Melbourne, Australia. Couples using this method chart the woman’s natural signs of fertility and infertility each day without the use of temperature. Considered the simplest of all modern methods, it is now taught and used in over 120 countries around the world. International studies show the Billings Ovulation Method to have an effectiveness rate of 99.15 percent for the avoidance of pregnancy. (Like all natural methods, the Billings Ovulation Method can be reversed at any time in order to achieve pregnancy.)

CREIGHTON MODEL FertilityCare™ System

The CREIGHTON MODEL FertilityCare™ System relies upon the observation of biological markers that are essential to human fertility and a woman’s health.  These biological markers tell the couple when they are naturally fertile and not fertile.  The FertilityCare™ System has been extensively evaluated over the past 24 years through research, first at St. Louis University and Creighton University Schools of Medicine, and most recently at Pope Paul VI Institute for the Study of Human Reproduction (Omaha, Nebraska).  Because of its standardized and objective format, it has been instrumental in the development of a new reproductive and gynecological science called NaPro TECHNOLOGY®.  This new science allows a woman to monitor and maintain her procreative and gynecologic health.

Sympto-Thermal Models


Northwest Family Services

Northwest Family Services provides a Sympto-Thermal Method of Natural Family Planning based on the research of Dr. Josef Roetzer. This highly effective and adaptable program is designed to be offered in small groups, one-to-one, or distance learning and includes individualized follow-up applicable to all reproductive situations. The instructional approach involves learner-centered activities. The client instruction course is available in both English and Spanish.

An NFP Provider Education Program along with certification is also available. NWFS meets all the national standards set for the Diocesan Development Program for NFP. In addition, NWFS provides considerable resources in the area of abstinence and chastity education with web sites available at and For further information contact: Northwest Family Services, 4805 NE Glisan Street, Portland, OR 97213, 503-215-6377 or FAX 503-215-6940.

Couple to Couple League International

The Couple to Couple League (CCL) is an international, Catholic, non-profit organization dedicated to promoting and teaching fertility awareness (natural family planning) to married and engaged couples. It is essentially a volunteer organization because services are provided by professionally-trained volunteers who are supported by a small staff at the international headquarters in Cincinnati, Ohio. Local Chapters of the organization consist mainly of certified Teaching Couples and Promoters, along with other supportive members.

Their approach

CCL has a three-fold approach to teaching NFP:

  1. The full Sympto-Thermal Method of NFP.
  2. The moral underpinnings for the NFP decision.
  3. The promotion of exclusive and continued breastfeeding and its effect on fertility.

Modified Sympto-Thermal Model


Marquette Model

Marquette University College of Nursing Institute for Natural Family Planning (INFP) was established in 1997 for the purpose of providing professional education, research and service in natural family planning (NFP). Reflecting the mission of Marquette University the mission of the INFP is to serve God by contributing to the advancement of knowledge in NFP and by collaboration with the Catholic Church in local, state and national NFP programs.

Marquette University College of Nursing has been providing professional services in NFP since 1985. In 1999 a new method of NFP was developed at Marquette University that integrates new technology (the ClearPlan Easy Fertility Monitor – Unipath Diognostics) with traditional natural biological markers of fertility. The ClearPlan monitor is a hand held device used to measure urinary female hormones that can help a woman confidently determine her fertile time. The Marquette Model of NFP is currently being evaluated in a number of cities in the United States including Milwaukee, Madison, Atlanta, and Oklahoma City.