Where do I place a cover line?

What is a cover line?

A cover line (CL) is a tool used to more easily visualize temperature values on your chart. This horizontal line is placed on a cycle chart when applying calculation rules to check if your temperature shift (TS) is high enough to validate ovulation has occurred. 

Where do I set my cover line? 

There are a number of different TS calculation rules out there. If you have been learning a specific fertility awareness method*, please refer to your resources/instructor to find your temperature calculation rules. If you are not familiar with a method, here is a simple set of rules to set your CL and calculate your temp shift. 

First, round your temperatures on your chart as this makes applying the rules easier. Before you add your horizontal line, wait until you have at least  three temperatures that are all higher than the previous six temps before they jump. Once you have 3 temperatures that are higher, set your cover line through the highest of the six lower results and use that line to apply one of the following calculation rules. 

Standard temperature rise

The third temperature must reach at least 0.4F/0.2C above your cover line. 

Slow rise temperature shift

If the third temperature does not reach a minimum of 0.4F/0.2C, wait for a 4th temperature. Four temperatures above the cover line is a slow rise TS. 

Fall back temperature rise

If the second or third temperature drops back down to or even below the line, wait for a fourth temperature. The fourth temperature must reach at least 0.4F/0.2C above the line to confirm a valid temperature rise. 

Important note: You cannot mix a combination of these rules, only one can apply to validate your TS. If your temperatures don't meet the criteria of one of these calculations, remove your cover line and wait until you see a new possible rise to try again. 

If one or two of your pre or post-rise cycle days are missing a temperature result, you can still apply the same calculations by skipping the missed days and adding the next temp result into your count. Always base your count on the number of  temperatures, rather than days (i.e. if the day before your rise is missing a result, count back an extra day to ensure you have 6 valid temps). Too many missing results would mean you are unable to make an accurate interpretation.

Setting a cover line in the Tempdrop app

The Tempdrop charting app has an option to apply a cover line and mark your own temperature shift when it's used in manual mode. Click here to learn how to use the manual mode features. 

Not ready to work out your own temperature shift? Upgrade to Tempdrop premium and the app will do the work for you.

*Some popular methods and organizations that teach method rules are Taking Charge of Your Fertility (TCOYF), Sensiplan, SymptoPro, Couple to Couple League, and NFPTA.

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