How to Tell If a Basal Thermometer Is Defective

A basal body temperature thermometer is used for detecting ovulation in women attempting to conceive. The thermometer's accuracy is based solely upon the method used to chart your cycle, meaning each reading must be taken consistently, according to BabyHopes.com. Your basal temperature is taken orally, vaginally or rectally. Basal temperature is the base temperature at which your body rests when nothing is being required of it. A defective thermometer might be the cause of wildly fluctuating temperatures, but determining if this is true is a process of elimination.

Things You'll Need

• Alarm clock
• Basal body thermometer

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Instructions

• 1

  Schedule a consistent time of morning you will take your temperature. For an accurate reading, it should be as close to the same time every morning as possible as your temperature will be lower the earlier it is and rise slowly throughout the day. Set your alarm, and take your temperature when it goes off.

• 2

  Take your temperature before doing anything. This includes shaking down the thermometer if you are using a glass model; do that the night before, as even this small movement will raise your temperature and make your thermometer reading inaccurate.

• 3

  Use the same method each time, whether orally, vaginally or rectally. Consistency will increase the accuracy of your reading.

• 4

  Chart your results. This is the best way to use your thermometer accurately and help to determine if your thermometer is defective. As each person's body temperature is different, the thermometer should read consistently within 0.5 of a degree throughout your cycle. For instance, if you begin at 97.6 degrees on the first day of menses, it should rise and fall 0.2 to 0.4 of a degree around ovulation. Replace a thermometer showing more variation than that or an inconsistent variation from month to month.