One of the many changes that take place in a woman's body during her menstrual cycle is an increase in body temperature at the onset of ovulation. During the first the first part of a woman's cycle, the body temperature is lower. With ovulation, the body temperature rises (to create a more fertile environment for the fertilized egg) and remains higher until the beginning of a woman's next cycle.

Recording each day's body temperature - and charting the patterns of temperature change - will help pinpoint when when ovulation has occurred.

Because BBT charting allows a woman to confirm the onset of ovulation, it is a very useful method in helping facilitate conception - as well as understanding the general patterns and nuances of a woman's menstrual cycle.

During the first two weeks of a woman's cycle, her body temperature is lower (97.0 to 97.5 F), due to the presence of estrogen. With ovulation, a rise in body temperature takes place - caused by an increase of the hormone progesterone - in order to provide a warmer, more fertile environment in the womb. A minimum temperature rise of 0.4 to 0.6 degrees F can be measured - and this change will last through the duration of the menstrual cycle. By monitoring when this temperature change takes place, you can estimate when ovulation has taken place.

How to take your Basal Body Temperature
	Purchase a basal body temp (Basal Body Temperature) thermometer.
	Obtain a Basal Body Temperature chart from your doctor, or download one from here.
	Before bedtime, place Basal Body Temperature chart, a notepad and pen on bedside table or floor.
	At bedtime, prepare your thermometer: if mercury, shake down below 98 degrees.
	Place thermometer within arm's reach on bedside table or floor.
	Upon waking in the morning, immediately reach for thermometer before doing anything else.
	Insert thermometer into mouth, under tongue.
	If mercury thermometer, leave in mouth for 5 minutes.
	If digital thermometer, leave in mouth until indicator (usually a beep) signals you.
	After 5 minutes or the signal sounds, take thermometer out of mouth and look at the reading under good light.
	Jot down date and temp reading on notepad.
	Scribble a pen dot on the graph line where the date and temperature meet.
	After you have more than one temp graphed, connect the dots with a line.

Other Tips
Do not do anything else before placing thermometer in your mouth. If possible, don't move any body part other than your reaching arm.
Jot down temperature reading immediately; do not depend on your memory.

Your Basal Body Temperature can be taken orally with a special BBT thermometer. Ideally, a larger thermometer that registers from 96 to 100 degrees (in easy-to-read one-tenth degree increments) is recommended. Digital thermometers are also available. Remember, you are attempting to discern as little as a two-tenths of a degree of difference in temperature, so selecting a quality thermometer and following directions are crucial.

Important: Your BBT temperature refers to a 'resting' or 'base' temperature. That means that your BBT must be measured prior to any physical activity, after at least three to four hours of sleep. Make sure that you read thermometer directions - and if you have any questions or unique considerations, consult your physician.