Recording the body temperature each morning was originally started by the Catholic Church as a form of contraception. Unfortunately it had a low success rate due to women’s cycles changing from one month to another, and varying in length and rhythm. I always ask my female fertility patients to try and record their temperatures, and with some women they find it empowering to see how their body is functioning on a deeper level. They also find that it cushions the disappointment of not being pregnant when the temperature drops at the end of the cycle.

However, some women find it very stressful and that it accentuates the already high levels of worry involved with trying to get pregnant. In cases like this we try and get a couple of months temperatures and then stop, as stress can be a major factor in obstructing conception.

How to take your morning temperature

Either a mercury or a digital thermometer can be used. On waking in the morning, having had at least 3 hours uninterrupted sleep and before getting out of bed, place the thermometer in the mouth for 3-5 minutes. Remove the thermometer and record the temperature on the BBT chart under the correct day of the cycle. It is important that the temperature is recorded at roughly the same time every day, as waking later raises the body temperature. Some studies have shown that the temperature rises 0.09 degrees C for each hour of delayed rising in the morning. Therefore, the BBT chart can be adjusted accordingly.

On most charts there are many additional boxes to add other information like cervical mucus , breast tenderness, date of sexual intercourse, sleep patterns etc. There are many BBT charts that can be found and downloaded from the internet, and there is also a book of charts with a thermometer in a wallet that can be bought from “Boots” the chemist.

Diagnosing patterns with the BBT chart

The current methods of analysing the BBT chart came from doctors working in fertility clinics in China. This information has filtered through to acupuncturists like me via very respected practitioners and authors in the treatment of infertility. Jane Lyttleton is one of them, and to her I am very grateful and have a huge amount of admiration and respect.

I diagnose the chart in 3 parts.

First I look at the follicular phase which runs from day 1 of the menstrual cycle up to ovulation.

Secondly, ovulation itself, and thirdly the luteal phase which is the period between ovulation and the beginning of the next cycle.

The follicular phase

The average temperature range for the follicular phase is 36.2 - 36.5 degrees C. It is the time in the cycle when the follicle is growing and then released as a mature egg at ovulation. The length of the follicular phase usually determines the length of the menstrual cycle. In women with a 28 day cycle, the follicular phase will normally be 14 days, however, a woman with a 35 day cycle may have a follicular phase of 21 days. As a TCM practitioner I will always encourage the follicular phase to be around 14 days.

Summary of BBT patterns in the follicular phase

BBT Pattern Diagnosis Treatment Unstable follicular phase Liver or Heart Fire Calm the mind, clear Liver/Heart Fire Long follicular phase Kidney Jing, Yin o blood deficiency Tonify Kidney Jing and Yin after the period Nourish Blood Short follicular phase

Heat, usually from a Yin deficiency

Clear the Heat and nourish the Yin Low follicular phase

Cold from Yang deficiency

Tonify and warm the Yang throughout the cycle High follicular phase

Heat, usually from a Yin deficiency

Clear the heat and nourish the Yin

Ovulation

The marked change on the BBT chart around ovulation comes from the effect of the release of progesterone from the ovary. In most women, this release of progesterone produces a rise in temperature of around 0.4 – 0.5 degrees C. This progesterone surge and warming of the body is important for conception and the maintenance of pregnancy, and the temperature should remain risen throughout pregnancy.

There is another change on the BBT chart which appears just before the progesterone surge. This is an oestrogen surge which causes a drop in temperature, however, this does not show on every chart. The reason for this is that the peak only lasts 12 hours, so if the surge comes at 11am until 11pm it may not show up on an early morning reading. This oestrogen surge also stimulates the fertile mucus experienced at ovulation.

The Luteal Phase

The temperature readings taken in the luteal phase should be more steady than in the follicular phase. Ideally, BBT readings should not vary by more than 0.1 degrees C. Once the temperature has lifted after ovulation, it should be maintained at this level for 11–14 days (preferably 13–14 days).

I’m sure that there are many women in Sussex cursing me as they fumble around for their thermometers first thing in the morning. But as can be seen , the information that the BBT chart gives us, builds on all of the other information taken when diagnosing, to create a much clearer picture of what is going on.

Article written by Anthea Mason - qualified acupuncturist and specialised in fertility

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