Hypothyroidism: recognising, screening and treating it in 2026

1. What is hypothyroidism?

Hypothyroidism is a chronic condition in which the thyroid gland, located at the base of the neck, no longer produces enough thyroid hormones (T3 and T4). These hormones regulate metabolism: body temperature, heart rate, digestion, energy, mood, weight and fertility. When they decrease, the entire body slows down.

In Belgium, around 5 % of adults are affected, mostly women over 50. The most common cause is Hashimoto's thyroiditis, an autoimmune disease in which the immune system gradually destroys the thyroid. Recent studies (Lancet 2024) confirm a rising incidence, partly explained by improved screening.

2. Warning signs to watch for

Hypothyroidism develops slowly and its symptoms are often wrongly blamed on stress, age or simple tiredness. The most common signs are:

• persistent fatigue and daytime sleepiness
• unexplained weight gain despite stable diet
• cold intolerance, cold hands and feet
• dry skin, brittle hair, fragile nails
• constipation and bloating
• poor concentration, slow memory, low mood
• irregular or heavy periods, infertility
• muscle cramps and bradycardia (slow pulse)

In pregnant women, untreated hypothyroidism increases the risk of miscarriage and can affect the baby's neurological development: early screening is essential.

3. How to screen for it?

Screening is simple and reliable: a blood test measuring TSH (thyroid-stimulating hormone). A high TSH indicates hypothyroidism. If abnormal, the doctor adds free T4 and anti-TPO antibodies to confirm an autoimmune origin.

European guidelines (ETA 2024) recommend targeted screening for: women over 50, pregnant women or those planning pregnancy, patients with family history of thyroid disease, people on lithium or amiodarone, and anyone with suggestive symptoms. At Maison Médicale Parc Astrid, this work-up is included in the INAMI flat-rate, with no upfront payment.

4. What are the treatments?

The standard treatment remains levothyroxine (L-Thyroxine®, Euthyrox®), a synthetic hormone identical to the one produced by the thyroid. Taken fasting, in the morning, 30 minutes before breakfast, it gradually restores metabolism. The dose is tailored to weight, age and cardiovascular status.

Updated 2025 recommendations stress that you should not change brand without medical advice (bioavailability varies slightly) and keep a 4-hour gap with calcium, iron or proton-pump inhibitors, which reduce absorption. Combined T4+T3 therapy is only considered when symptoms persist despite normal TSH, after consultation with an endocrinologist.

5. Follow-up at Maison Médicale Parc Astrid

Once diagnosed, your GP ensures long-term follow-up. TSH is rechecked 6 to 8 weeks after each dose change, then once a year when balance is reached. Consultations, blood tests and therapeutic education are fully covered by the flat-rate for registered patients.

Our medical team coordinates with the lab, the referral endocrinologist if needed, and the nurse for weight and blood pressure monitoring. During pregnancy, close monitoring is set up immediately, in line with Belgian 2024 guidelines.