Why perimenopause and thyroid dysfunction are often confused, and what thorough testing looks like

In integrative care, it helps to look at perimenopause and thyroid dysfunction together. Women in their 40s and 50s with fatigue, brain fog, weight gain, mood changes, poor sleep and thinning hair can have perimenopause, a thyroid problem, or both.

The symptoms overlap a lot

Look at the core symptoms of hypothyroidism: fatigue, weight gain, brain fog, feeling the cold, hair loss, constipation, low mood and irregular periods. Now look at the core symptoms of perimenopause: fatigue, weight gain, brain fog, poor sleep, mood changes, thinning hair and irregular periods. Because the overlap is large, it's worth looking at both possibilities when a woman in her mid 40s has these symptoms.

Understanding your thyroid results

TSH (thyroid stimulating hormone) comes from the pituitary gland and tells the thyroid how much hormone to make. A thyroid panel can include other markers too, and Reece goes through what each one measures with you.

A thyroid panel can include: [1]

• Free T3: the active thyroid hormone, which acts in the cells
• Free T4: the precursor, which has to be converted to T3
• Reverse T3: an inactive form of T3 that blocks T3 receptors, and is raised in chronic stress and inflammation
• TPO antibodies: the marker for Hashimoto's thyroiditis, the most common form of autoimmune hypothyroidism
• Thyroglobulin antibodies (TgAb): a second autoimmune marker, sometimes positive when TPO is negative

The link between perimenopause and the thyroid goes further

Sex hormones and thyroid function affect each other in complex ways. During perimenopause, oestrogen and progesterone levels swing up and down, and the pattern can be quite different from one woman to the next, before they eventually fall. [2] Oestrogen raises thyroid binding globulin (TBG), a protein that carries thyroid hormone in the blood. That's why starting oestrogen tablets, such as the pill or oral HRT, can change some thyroid test results, and why women already taking thyroid medication may need their dose checked. [3][4]

The autoimmune processes behind Hashimoto's thyroiditis are also influenced by changes in sex hormones. Many women first develop thyroid antibodies during perimenopause, after pregnancy or after other hormonal changes, which suggests that changes in oestrogen affect immune regulation in the thyroid directly.

If both are left untreated

Both conditions are common, and both can be assessed and managed with your GP. Reece can support you alongside them.

A thorough assessment in practice

When women come to Reece with perimenopausal symptoms, he goes through any recent results with them. If more tests could help, he may suggest a hormone and thyroid panel. It can include the thyroid markers above, along with oestradiol, progesterone, FSH, LH, DHEA-S, testosterone, SHBG, fasting insulin, HbA1c, full iron studies, vitamin D and B12. Reece talks you through the cost in your consultation, and Medicare doesn't cover these tests when Reece arranges them.

From there, your plan is tailored to you. It may include acupuncture and changes to your diet and lifestyle. Herbal medicine and supplements are only considered after a full consultation, and Reece discusses the options and costs with you first.