What is a thermal shift?

iVillage Member
Registered: 05-31-2004
What is a thermal shift?
Tue, 07-13-2004 - 11:15am
I'm new to charting. It says that ovulation occurs on the day before your thermal shift. I don't know what that means. I have also been using the Clearblue Easy Fertility monitor. I wonder if I am ovulating a few days later then what the monitor is telling me. Thanks, Susan
iVillage Member
Registered: 12-31-2003
Tue, 07-13-2004 - 11:38am

A thermal shift is three days of sustained higher temps. If you are using fertility friend for charting it will only put in a O date after it has seen three higher temps in a row. Then it places O the day before the shift. Some women get a second thermal shift after O (triphasic chart) which sometimes suggests implantation has occurred.


iVillage Member
Registered: 04-04-2004
Tue, 07-13-2004 - 12:01pm

Hi Susan,

I also use a fertility monitor (same company

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