Is it thyroid, diabetes or perimenopause? Telling them apart

Key takeaways

• Perimenopause in women over 45 is diagnosed from symptoms and cycle changes, not a hormone blood test, according to NICE.
• Thyroid and diabetes, by contrast, are diagnosed with blood tests, and these are quick and inexpensive.
• An underactive thyroid causes tiredness, feeling cold, weight gain, constipation and heavy periods. An overactive thyroid causes heat intolerance, sweating, palpitations, anxiety and weight loss.
• Type 2 diabetes often has no symptoms. When present, they include thirst, frequent urination, tiredness and recurrent thrush.
• Having one condition does not rule out the others. Treating the thyroid will not stop hot flushes, and hormone therapy will not fix high sugar.

Why are these three so easy to confuse?

A woman comes in and says, "Doctor, my thyroid report is normal, my sugar is normal, so why do I feel like this?" Or the opposite: "I've been told it's my thyroid, but the tablets haven't helped the sweating." Both happen because these three conditions look so alike from the outside.

They also arrive together in the same decade. The NHS notes that Hashimoto's disease, the most common cause of an underactive thyroid in the UK, is more common in women and usually begins between about 30 and 50. Type 2 diabetes becomes more common with age and weight around the middle, and Indians tend to develop it at lower body weights. And perimenopause usually starts in the 40s. Three guests arriving at the same party, all wearing similar clothes.

All three can make you feel tired, foggy, irritable and "not myself". The point is: don't guess. A short history and two or three tests are usually enough to sort it out.

How do the symptoms compare?

Symptom lists for thyroid and diabetes come from the NHS. Perimenopause symptoms are also described by the NHS. No single symptom proves one condition.

Which tests actually help?

For thyroid: TSH, sometimes with free T4. This is the standard first test. An abnormal result may lead to further tests such as thyroid antibodies.

For diabetes: HbA1c, or fasting plasma glucose. HbA1c reflects your average sugar over about three months and does not need fasting. Many women in their 40s have prediabetes without knowing it.

Haemoglobin and ferritin. Heavy periods in the 40s are common and cause iron deficiency, which brings its own tiredness, breathlessness and hair fall. See heavy periods in your 40s.

Vitamin D and B12, if there are aches, numbness or marked fatigue, or if you are vegetarian.

Lipids and blood pressure, because all three conditions affect heart risk.

For perimenopause: usually no hormone test. NICE guidance says that in women over 45, perimenopause should be diagnosed from symptoms such as hot flushes and irregular periods, without lab tests. It advises against using AMH, estradiol or other ovarian tests to diagnose perimenopause or menopause. FSH may be considered for women aged 40 to 45 with symptoms, or under 40 when early menopause is suspected. Hormone levels swing from day to day in perimenopause, so one normal report does not rule it out. Symptoms are symptoms. You can read more in do you need a hormone test for perimenopause?

What if I have more than one?

This is common, and each needs its own treatment:

• Thyroid treated, still flushing? If your TSH is now normal on treatment but you still have hot flushes, night sweats, poor sleep and irregular periods, the thyroid is no longer the explanation. Perimenopause is likely, and its symptoms can be treated too.
• Diabetes and perimenopause. Poor sleep and hormone changes can make sugar control harder, and high sugar can worsen urine infections and thrush. Better sleep and regular strength training help both.
• Thyroid medicine dose. If you start hormone therapy and are on thyroid medicine, your doctor may recheck your TSH after a few weeks, as needs can change.

A good plan treats each condition properly instead of blaming everything on one.

What questions should you bring to your doctor?

• When did my periods start to change, and how?
• Do I have hot flushes or night sweats, and how often?
• Is there a family history of thyroid disease, diabetes or early menopause?
• Have I had my TSH and HbA1c checked in the last year?
• Is my haemoglobin normal if my periods are heavy?
• What should we recheck, and when?

Keeping a simple diary of your periods, flushes, sleep and mood for two or three months is very useful. A notes app on your phone is enough. Honestly, it tells me more than a stack of reports.

How I approach this at Dr Tvacha

At Cocoon × Dr Tvacha in Thane West, the Midlife Women's Health Check within The Right Stop Programme starts with a long conversation through every symptom. I order only the tests you need, usually general bloods including thyroid and sugar where indicated, rather than a large package, and explain what each result does and does not mean.

Written by

Dr Anagha KarkhanisGynaecologist and Fertility Specialist · Reg. No. 2006/02/1187

Leads midlife women's health at Cocoon × Dr Tvacha, Thane.