Taking your basal body temperature (BBT) is very easy and only takes a few minutes. (Is basal body temperature a reliable source to confirm the occurrence of ovulation?) It's important, however, to follow some general rules:
- Measure your basal body temperature every morning after at least three hours of uninterrupted sleep.
- Take your temperature before rising or doing anything else, like taking a sip of water, making a phone call, or going to the bathroom. Keep the thermometer by your bed, so that you don't have to look for it in the morning.
- Measure your BBT at the same time, or within a half-hour of this time, every day. Note down the time of the measurement.
- If you're using a digital thermometer, wait for the signal or beep (usually about one minute). If you're using a glass thermometer, wait about five minutes. Remember to shake it before going to bed, so you don't make sudden movements in the morning before taking your temperature.
- Take your BBT orally or vaginally. Decide on one or the other, because your temperature varies between the two.
- Don't change the type of thermometer you use during the course of the cycle. This may distort your results. (What factors may distort the reliability of basal body temperature measurement?)
Try to note down or enter your BBT as soon as possible after taking your temperature (if you don't have a computer nearby, keep a notepad and pen by your bed.)