Hypothyroidism: recognising, screening and treating it in 2026

1. What is hypothyroidism?

Hypothyroidism is a long-term condition in which the thyroid gland, at the base of the neck, no longer makes enough thyroid hormones (T4 and T3). These hormones control metabolism: body temperature, heart rate, bowel function, energy, mood and weight. When they run low, the whole body slows down.

Hypothyroidism is common. Its most frequent cause is usually Hashimoto's disease, an autoimmune condition in which the immune system gradually attacks the thyroid. It mainly affects women and usually starts between the ages of 30 and 50.

2. Warning signs to watch for

Hypothyroidism often develops slowly, and its symptoms are easily put down to stress, age or simply being tired. The most common signs are:

• extreme tiredness
• feeling cold more than usual
• weight gain
• constipation
• difficulty concentrating
• low mood or depression
• dry skin, dry hair or hair loss
• a hoarse voice
• irregular or heavy periods

During pregnancy, untreated or under-treated hypothyroidism increases the risk of miscarriage, and severe untreated hypothyroidism in the mother can affect the baby's brain development. That is why proper testing and follow-up matter.

3. How to screen for it?

Diagnosis is based on a blood test measuring TSH (thyroid-stimulating hormone) and, if needed, T4 (thyroxine). A raised TSH points to hypothyroidism. Your doctor may also check for anti-TPO antibodies, which indicate an autoimmune cause. For registered patients, the blood test can be done at the practice by our nursing team.

The test is offered when symptoms suggest a thyroid problem. According to the UK's NICE guideline, it is also recommended for people with type 1 diabetes or another autoimmune disease, or with new-onset atrial fibrillation. Type 2 diabetes alone, however, is not a reason for testing.

4. What are the treatments?

The standard treatment is levothyroxine, a synthetic hormone identical to the T4 made by the thyroid. It is taken once a day on an empty stomach, 30 to 60 minutes before breakfast or before any drink containing caffeine, with a glass of water and ideally at the same time each day. The dose is tailored to each person.

Some products can make it work less well, including calcium and iron supplements and antacids (indigestion remedies): ask your doctor or pharmacist how to space them out. Biotin (vitamin B7), found in some supplements, can distort thyroid test results. Liothyronine (T3) is not routinely added.

5. Follow-up at Maison Médicale Parc Astrid

Once the diagnosis is made, your GP provides long-term follow-up. According to NICE, TSH can be checked about every 3 months after starting treatment or changing the dose until it is stable, and then once a year.

If you become pregnant, tell your doctor promptly: levothyroxine needs often increase, and TSH is usually checked about every 4 weeks during the first half of pregnancy.

Our medical team coordinates your care with the laboratory, an endocrinologist if needed, and the nurse for weight and blood pressure checks. For registered patients, consultations take place under the flat-rate system: no payment at the consultation; your health insurance fund pays the practice a monthly flat fee.

Sources

• NICE (UK) – Thyroid disease: assessment and management, guideline NG145 (2019, updated 2023)
• NHS – Underactive thyroid (hypothyroidism) (2025)
• NHS – Levothyroxine (2026)
• American Thyroid Association – Hypothyroidism in pregnancy