These signs – also known as indicators or biomarkers – can provide health insights and allow you to avoid or achieve pregnancy.
The same thing as fertility awareness. Those who practice fertility awareness record their observations in a “chart” (paper or app) so this practice is often known as cycle charting.
Each method has its own set of indicators and guidelines for identifying the open / close of the fertile window.
Single-check methods rely on cervical fluid or cervix observations alone to open the fertile window. Examples include Justisse and The Well.
Double-check methods add a cycle-based calculation as a conservative buffer to open the fertile window. Examples include Sensiplan and SymptoPro.
Examples with luteinising hormone (LH) tests include FEMM.
Examples with the Clearblue fertility monitor which tracks changes in estrogen and LH include Marquette and Boston Cross Check.