Essential Sameness Pattern and Yellow Stamps

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

The Essential Sameness Pattern (ESP) and Yellow Stamps are the CrMS construct for charting infertility windows when continuous discharge is present: the ESP defines pre-Peak infertile days through day-to-day identical observations, and Yellow Stamps are the chart symbol that records those days.⁷⁸

In women with chronic or continuous discharge, the standard green-stamp infertile day rule does not apply. The ESP addresses this. When a woman observes the same discharge pattern on consecutive days before Peak, those days carry the same fertility status as dry days in a standard cycle. The chart records them with a Yellow Stamp, indicating infertility despite the presence of discharge.

Post-Peak Yellow Stamps apply from Peak+4 onward in qualifying continuous-discharge cycles. Pre-Peak Yellow Stamps require the ESP criteria to be met. Both require formal instruction by a certified FertilityCare Practitioner. The ESP and Yellow Stamp system is what makes CrMS usable for women whose charts would otherwise appear uniformly fertile.

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.