The Billings Ovulation Method , BOM (Abkürzung)

This model, like the Billings ovulation method, is based on observations of cervical mucus to track fertility.

John Billings, 89, Australian co-developer of the Billings ovulation method.

Two well-known mucus-only methods are the Billings ovulation method and the Creighton Model FertilityCare System.

Working with his wife, Dr. Evelyn Billings, a pediatrician, he created what is now known as the Billings ovulation method, or the Billings method.

Hilgers describes the Creighton Model as being based on "a standardized modification of the Billings ovulation method", which was developed by John and Evelyn Billings in the 1960s.