Q: Which factors other than fertility affect the BBT?

A: Several factors other than fertility can affect the BBT. These factors include:

• Using a new thermometer in the same cycle.
• Emotional excitement. 
• Sex shortly before taking the temperature.
• If you have a fever. 
• Drinking alcohol the previous night. 
• Taking BBT after less than 3 hours of consecutive sleep. 
• Taking BBT at a different time. 
• Using a heating pad or electric blanket.