Thyroid Issues & Your Cycle How Imbalance Affects Menstrual Health

The Central Role of the Thyroid

Our thyroid gland may be small and inconspicuous, but it plays a very important role in our body. It acts like the conductor in an orchestra, and has a significant influence on our metabolism, which in turn controls numerous vital processes. The hormones produced by the thyroid gland, in particular thyroxine (T4) and triiodothyronine (T3), act like musical notes that conduct the harmonious interplay of all bodily functions. They influence energy consumption, regulate the heartbeat, influence body temperature and the menstrual cycle. In short, thyroid hormones are the beats to which our body dances and works.

Basal temperature, which is influenced by thyroid hormones, provides insights into thyroid function. A temperature between 36.4°C and 36.9°C is considered normal, while values below 36°C may indicate a possible underactive thyroid.

This is particularly relevant for couples trying to conceive, as thyroid issues can often cause fertility challenges. Therefore, monitoring basal temperature is an easy way to detect potential health problems early on.

What happens if your thyroid function is impaired?

An underactive thyroid is called Hypothyroidism

If your thyroid function is impaired, this can lead to a real mess in the orchestra of our organism. An underactive thyroid is known as hypothyroidism, which leads to symptoms such as chronic fatigue, weight gain, sensitivity to cold, and even depression. An underactive thyroid can disrupt the regulation of the menstrual cycle, which can lead to irregular periods and difficulties in conceiving. It is therefore very important to keep an eye on thyroid function, especially for couples who want to start a family.

An overactive thyroid is called Hyperthyroidism

In contrast, an overactive thyroid, or hyperthyroidism, can lead to restlessness, unwanted weight loss, palpitations, and excessive nervousness. The effects of impaired thyroid function are manifold and can significantly impair quality of life.

What is the Broda Barnes temperature measurement method?

Developed by Broda Barnes M.D., this method is based on the measurement of basal body temperature. In essence, the basal body temperature is directly influenced by thyroid hormones. If the basal body temperature is between 36.4°C and 36.9°C, this indicates normal thyroid function.

In contrast, an average temperature below 36°C indicates a possible hypothyroidism. This can be particularly important for couples who are trying to conceive, as impaired thyroid function can be a common reason for difficulties in conceiving.

As a thyroid disorder often develops gradually and has no clear, obvious symptoms and they are initially so mild that they are not necessarily associated with a functional disorder, the basal body temperature offers a valuable method to notice problems earlier.

How can you use the method?

Increased average value

A relatively high average temperature (with frequent values above 36.9), may indicate hyperthyroidism, as shown in the example curve, may indicate hyperthyroidism.

Other symptoms of hyperthyroidism may include:

long menstrual cycles
low menstrual bleeding
General restlessness and nervousness
rapid, increased sweating

However, despite the increased average temperature, the basal body temperature curve shows the typical picture with a rise after ovulation and a significant increase during the luteal phase.

Important: Whether you really suffer from hyperthyroidism can only be diagnosed by a doctor.

Low average value

A relatively high average temperature (with frequent values above 36.9), may indicate hyperthyroidism, as shown in the example curve, can indicate a possible hypothyroidism. If your wake-up temperature is below 35°C, the DaysyDay app will notify you after synchronization. Temperatures below 35°C are automatically excluded by the algorithm.

Other indications of hypothyroidism can be:

absence of menstruation or amenorrhea
persistent heavy periods
irregular cycles
cycles without ovulation (no rise in temperature)
short luteal phase
strong temperature fluctuations

However, despite the low average temperature, the basal body temperature curve shows the typical picture with a characteristic rise after ovulation and a significant increase during the luteal phase.

Important: Whether you really have an underactive thyroid can only be diagnosed by a doctor.

FAQs

Why should I track my basal temperature at all?

Because it’s a simple, non-invasive way to gain insights into your metabolism, cycle health, and fertility. Consistently low or high readings can alert you to seek medical advice sooner rather than later.

What if my temperature is often outside the normal range?

Don’t worry immediately. Occasional fluctuations are normal, but consistently low or high values may point toward an underactive or overactive thyroid. In that case, a doctor can run further tests.

Why is the thyroid especially relevant for fertility?

Thyroid dysfunction can disrupt ovulation and the menstrual cycle. By keeping an eye on your basal temperature, you gain insights that may help explain difficulties conceiving and support earlier medical evaluation.

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Thyroid and Your Menstrual Cycle How Hypothyroidism and Hyperthyroidism Affect Fertility