Details, from CNS:
Dr. Evelyn Billings, who with her husband, John, pioneered research that led them to develop a form of natural family planning supported by the Catholic church, died Saturday after a short illness. She was 95.
The Australian pediatrician joined her physician-husband’s team in 1965 as he was researching a more reliable method to prevent pregnancies than the rhythm method, known as the “calendar” method, which was developed in the 1930s.By the late 1960s, the research team had established the procedures for identifying fertile days and teaching centers began to be set up around the world.
The method, known as the Billings ovulation method, allows women to monitor periods of fertility through close examination of naturally occurring physiological signs, and use that information to prevent pregnancy or space births.
Methods of natural family planning, or NFP, are approved by the church as a morally acceptable way for Catholic couples to plan their families.
Evelyn Billings co-wrote “The Billings Method” with medial journalist Ann Westmore in 1980. It has since undergone seven new or revised editions, 16 printings, and has been translated into 22 languages.
According to the World Organization of Ovulation Method Billings, known as WOOMB, women in more than 100 countries practice the method.