Rules of the Billings Method*

The Early Day Rules (rules that apply before a peak is recognised)

Rule 1: Avoid intercourse on days of heavy bleeding during menstruation.

Rule 2: Alternate evenings are available for intercourse when these days have been recognized as infertile (see Basic Infertile Pattern).

Rule 3: Avoid intercourse on any day of change that interrupts the Basic Infertile Pattern. Allow 3 days of Basic Infertile Pattern afterwards before intercourse is resumed on the fourth evening. Rule 2 continues.

The Peak Rule

Rule 4: When the Peak is identified following a change from the BIP, the Peak Rule is applied. From the beginning of the fourth day following the Peak until the end of the cycle intercourse is available every day at any time.

To Achieve pregnancy

To achieve pregnancy, intercourse is recommended around the Peak day.

* Dr Evelyn Billings & Dr Ann Westmore, The Billings Method, Penguin Books Australia Ltd, 2008.