Basal Body Temperature (BBT)
For most women there are only about 30 days in a year when there is a reasonable chance of conceiving. For a successful pregnancy outcome a whole chain of events need to come together precisely in the woman’s body, in her partners body and in their relationship in one of those days. Being able to accurately identify these relatively rare opportunities raises the odds of success considerably watching external clues such as the BBT charts provides us with a method to do exactly that. The BBT chart records the temperature of the body on working. It is called basal because it is measured at a time when the body is deeply rested and the metabolism and temperature rises after a woman has ovulated and begins to produce progesterone. In a typical menstrual cycle a BBT chart looks like this:
The BBT chart will tell us the following:
- Whether or not ovulation has taken place.
- Adequate production of progesterone (which is required to maintain a successful pregnancy).
- The length and pattern of the luteal phase (day 1 to ovulation).
- The length and pattern of the follicular phase (ovulation – start of menstrual cycle).
Dysfunctions in any of these areas will cause problems in conception and/or maintenance of a healthy pregnancy. The beauty of Chinese medicine is its ability to correct any of these dysfunctions and prepare the body for a healthy pregnancy and birth.
Taking your BBT
Upon waking the temperature is taken preferably using a digital thermometer. This must be done after a minimum of 3 hours uninterrupted sleep and preferably at the same time each morning. If, on the weekend you are taking your temperature later make a note of it, or if alcohol was consumed the night before, or if you were unwell/restless. These will all cause your core temperature to rise.
Problems in the BBT
a) When follicular phrase is too low (i.e. temps of below 36.0).
This can indicate a very low metabolism or a low thyroid function. In Chinese medicine this will indicate a spleen and kidney Yang deficiency.
b) When follicular phrase is too high (i.e. temps of 36.6 and higher).
This can indicate a high metabolic rate or an over active thyroid or in Chinese medicine a ‘heat’ condition which will lead to a poor production of cervical mucus and a thin endometrial lining (womb lining). Also this can point to endometriosis.
c) When the follicular phrase is too short (i.e. 9-10 days).
This will lead to a poor ovulation of an immature egg with a poor womb lining as there has been insufficient time to nourish it. Generally caused by heat (usually Yin deficient heat).
d) When the follicular phrase is too long (i.e. 20 days or more).
The length of the menstrual cycle is determined by the length of the follicular phase. According to TCM if ovulation is delayed then one of the pre-requisite substances or conditions is absent or insufficient or the process of ovulation is obstructed (known as Qi Stagnation) or there is a Jing blood or Yin deficiency.
e) Unstable follicular phrase
The values of the BBT chart should be reasonably steady, not the same each day of course but not varying by more than about 0.2 or 0.3 C. Fever, lack of sleep or alcohol consumption can cause any of these high readings. Unexplained peaks and troughs will lead us to think of liver or heart fine. The patient will be encouraged to lead a more regulated life and reduce stress.