What Your Basal Temps Reveal About Thyroid Function

Author: Marilyn Shannon


by Marilyn Shannon

I am always amazed at the amount of information our simple charts provide us. We can tell with 99% accuracy if we are in an infertile phase of our cycle, yet a skeptical world resorts to immoral, ineffective, unhealthy and irreversible means to control their fertility. We can predict with a high degree of accuracy the most fertile time of our cycle, yet sales of expensive "ovulation predictor" kits continue to grow. No matter how irregular our cycle might be, we can tell whether or not we have ovulated and when the period is to be expected. And we never need tests to determine whether or not we are pregnant, because 21 days of elevated temperatures clearly indicate a pregnancy. When we do become pregnant, our charts even provide us with a due date which is more accurate and far cheaper than anything available medically.

Our charts also provide us with information about potential or real health problems. In my last article, for example I wrote about the hormonal defect called "short luteal phase." Cycles with short luteal phases may be a risk factor for osteoporosis, endometriosis and possibly even breast cancer. Reproductive specialists generally consider short luteal phase a "silent" disorder because women with it often have quite regular cycles. Yet a woman who charts her cycles can easily recognize a normal versus an abnormal luteal phase. What's more, short luteal phase can often be corrected with improved nutrition-if the woman is aware of it. (See CCL Family Foundations, March- April 1995, for further information on this topic.)

Thyroid Function and the Chart

But that's not all. I've been interested lately in two books by two different medical doctors who assert that the body temperature is a better indicator of thyroid function than any blood test you can take. The physicians, Broda O. Barnes, M.D., author of Hypothyroidism: The Unsuspected Illness, and E. Denis Wilson, M.D., author of Wilson's Syndrome: The Miracle of Feeling Well, make the case that modern medicine is missing the diagnosis of low thyroid function by relying on inaccurate blood tests to detect the disorder. Equally important, both doctors claim that modern medicine often treats low thyroid function with the wrong form of thyroid hormone replacement therapy. In this article I will emphasize Dr. Barnes' approach; my next article will cover Dr. Wilson's approach, which is quite different.

Dr. Barnes developed the "Barnes basal temperature test" for thyroid function as long ago as 1942. It relies on a morning, waking, underarm temperature, which Dr. Barnes believes should average 97.8 to 98.2 to indicate normal thyroid function. Dr. Barnes considers temperatures below 97.8 a possible sign of low thyroid function. These are preovulatory temperatures, to be taken on days 2 or 3 of the period in menstruating women, but on any day for other women, children, or men. His book states that the underarm basal temperature is about the same as the oral basal temperature.

In a chapter titled, "Menstrual Disorders, Fertility Problems, Unnecessary Surgery," Dr. Barnes gives clinical evidence and anecdotes to illustrate that treating low thyroid problems reduces menstrual problems such as heavy bleeding leading to "D&C" surgery and hysterectomy. He offers striking anecdotes of women with undetected low thyroid function who suffered many miscarriages, but who carried to term after thyroid treatment. He relates hypothyroidism both to male and female infertility.

Actually, CCL has taught for a long time that low thyroid function may cause several problems that can be seen on the chart:

* low basal temperature

* prolonged or constant less fertile mucus

* delayed or absent ovulation

* anovulatory cycles

* heavy menstrual bleeding

* infertility

Low thyroid function can cause or be related to other reproductive problems which do not appear on the chart:

* loss of desire

* premenstrual syndrome

* menstrual cramps

* repeated miscarriage

Because the thyroid hormones normally stimulate virtually every cell of the body, low thyroid function causes a variety of other physical symptoms in both men and women:

* fatigue

* weight gain

* anxiety or depression

* poor memory or concentration

* dry or itchy skin

* headaches

* frequent infections

* cold intolerance

Undetected Hypothyroidism

Women are more prone to low thyroid function than are men, yet many women who have several of the above symptoms, including the low body temperature, get completely normal results when they undergo blood testing for thyroid hormone.

Let me offer an example. A while ago, a young natural family planning user contacted me about her charts. Ovulation was being delayed more and more each month until it ceased altogether. What was more striking, though, was the level of her basal temperatures. They were all well below 97.0, more in the range of 96.6 to 96.8. She had also gradually gained a large amount of excess body weight. She had visited more than one doctor, but when they checked the obvious-her blood levels of thyroid hormones- they were normal. Doctors simply told her to lose weight.

Finally, a more thorough physician reviewed her history and carefully examined her charts knowledgeably. This doctor stated that she had many clinical and charted symptoms of low thyroid function, even slowed knee jerk reflexes, which are a seldom- checked but classic component of the low thyroid profile. He, too, however found complete blood testing for thyroid hormones to be within normal limits, and was reluctantly unable to help this woman.

While this example is more striking than most, I have had enough experiences like this in my NFP counseling that I have been puzzled for a long time about the contrast between the physical symptoms and the chart on the one hand, which seem strongly to indicate low thyroid function, and the blood tests on the other hand, which so often come out to be completely normal. Dr. Broda's work has provided at least some of the answers.

His book explains how the older tests for thyroid function - based on the patient's symptoms and on tests of oxygen consumption rate (basal metabolism, which is directly related to thyroid function)-were replaced in the 1940s by laboratory blood tests for thyroid hormone, not thyroid function. The results were a pendulum swing to the extreme. Many physicians came to look upon the results of laboratory tests as absolutes. If laboratory tests failed to indicate hypothyroidism, it could not be present- no matter what the patient's symptoms or even if a patient was already on thyroid therapy and benefiting from it. It was to be years before there began to be the recognition that the laboratory could not be the final arbiter.

Dr. Barnes' Approach

Dr. Barnes is now retired, but his work is being carried on through the Barnes Foundation. In addition to the basal body temperature and a health history, they recommend testing for low thyroid function by analyzing the hormone content of a 24- hour urine collection. They treat low thyroid function with desiccated thyroid which they believe to be a more effective treatment than the synthetic drug, Synthroid. They also test for other hidden hormonal problems, such as malfunction of the adrenal glands.

Having looked at many women's NFP charts for over 12 years, I must admit that I find quite high the Barnes figure of 97.8 (underarm basal and preovulatory) as indicating a possible thyroid problem. I have generally considered preovulatory temperature which produce a pre-shift base (PSB) less than 97.5 to be suspect if the symptoms of low thyroid function are present. When I see preovulatory temperatures crawling along the bottom of our charts at 97.0 to 97.2, I believe that the thyroid function is certainly on the low side compared to other women's. When temperatures keep slipping off the bottom of the chart, that is, they are below 97.0, NFP counselors often see other major irregularities, particularly delayed or absent ovulation.

Where Do I Start?

Does this information apply to you? If you are enjoying good overall health with sufficient energy to perform your daily tasks and to enjoy your times of recreation, lower than average temperatures should not concern you. (I personally can't push a thermometer up to 98.0 any time of the day or night, yet I am blessed with good health at this time. I suspect that my breastfeeding amenorrhea is the explanation.)

If you are troubled by some of the symptoms listed above and have noticed that your basal temperatures are on the low side, my advice is to start by applying the self-help suggestions on low thyroid function in my own book, Fertility, Cycles and Nutrition. Dr. Barnes' book does not mention the role of overall nutrition in thyroid function, but the thyroid gland needs a number of vitamins and minerals to function well. If improved nutrition is the answer, you may see the overall levels of your temperatures gradually rise.

If better nutrition doesn't help, you may wish to obtain further information about low thyroid function from the resources listed below. The next step is to discuss this information with an informed physician. You can obtain the name of a physician who is interested in Dr. Barnes' approach to low thyroid diagnosis and treatment through the foundation listed below.

Special Note to Infertile Couples

If you are experiencing unexplained infertility or repeated miscarriages, I strongly recommend that both of you carefully explore this approach. Doctors know that low thyroid function is an important cause of infertility, and if you have had fertility care, your blood has probably already been checked for thyroid hormones. Your test was probably normal, but Dr. Barnes' book will explain why the test was very probably unreliable.

Next Issue: Dr. Denis Wilson also believes that low body temperature may indicate low thyroid system function. His treatment is based on short-term use of "T3," which is the active form of the thyroid hormone. Specific self-help strategies to improve thyroid function will also be presented.

References and Resources

* Barnes, Broda O., M.D., and L. Galton (New York: Harper and Row, 1976).

* The Barnes Foundation, P.O. Box 98 Trumbull, CT 06611, (203) 261-2101. You may telephone and request their free packet of explanatory materials.

* Puglio, P. "Hypothyroidism: The Relationship to Menstrual Disorders," , Complimentary Issue II; available through the Barnes Foundation.

* Shannon, Marilyn, M. (Cincinnati: Couple to Couple League, 1992).

This article appeared in the May-June 1994 issue of CCL Family Foundations, Couple to Couple League, P.O. Box 111184, Cincinnati, OH 45211.