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  Evaluating Your Fertility
  Ovulation Calculator
  Fertility Calculator
  Body Temperature
  Luteinizing Hormone
  Seeing Your Doctor
  Understanding Fertility
  Maximise Your Fertility
  Infertility: An Introduction
  Infertility in Females
  Infertility in Males
  Implications of Infertility
  Questions to Ask Your Doctor
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Body Temperature

How can I tell when I am ovulating?
 
The answer is either by measuring basal body temperature (BBT), described below, or by using an  ovulation predictor kit to measure the level of   Luteinizing Hormone in the urine.

Basal Body Temperature (BBT)

Quite simply, the basal body temperature is your temperature on waking after a normal night’s sleep. In women who are ovulating normally, there is a rise in basal body temperature of approximately 0.5-1.0 degree C immediately after ovulation, which is maintained for the remainder of the cycle and falls back before menstrual flow begins. This temperature rise is due to the actions of progesterone, the hormone produced by the corpus luteum after ovulation. 

So, recording your BBT will tell you whether you are ovulating (ovulatory) or not (anovulatory) - and when ovulation is likely to occur.

Alternatively, the BBT test can also be used to determine the best time for you to try out other infertility tests with your doctor or consultant. 

It’s very easy to do, too. Just take your oral temperature each morning before engaging in any activity (eating, drinking or just moving about will change the body temperature). The basal thermometer measures temperature in tenths of degrees, which allows you to measure the smallest increase in temperature. 

You should record your temperature on a chart beginning on the first day of the menstrual cycle, at the onset of menstruation, to show daily temperature fluctuations throughout the cycle. 

Also log any events that may affect your temperature or fertility, such as intercourse, bleeding, sleepless nights or illness. A rise in temperature of about half a degree at the time of ovulation (about 14 days into the cycle) suggests ovulation has occurred.
  • Click here to download a Celsius version of the chart 
  • Click here to download a Fahrenheit version of the chart    
Example normal (top) and abnormal (bottom) BBT charts
 



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Last Updated: 5/6/2008

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