Billings Ovulation Method

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 7, 2026

A standardized FABM developed by Australian physicians Drs. John and Evelyn Billings in the 1960s, based entirely on the sensation and appearance of cervical mucus at the vulva to identify the fertile window. The Billings method requires no temperature taking and no instruments, making it globally accessible across cultural and resource settings; it has been studied in field trials supported by the World Health Organization. Users record daily observations according to standardized rules, identifying the "Peak Day" (the last day of fertile-type mucus) and counting subsequent infertile days. Published effectiveness data from large multi-country trials report method-related pregnancy rates of approximately 1% per year when used correctly to avoid pregnancy.⁸⁵ Billings is the foundational mucus-based method from which the Creighton Model was later standardized; it shares core mucus methodology with CrMS while remaining a distinct method with its own teaching network.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.