Thyroid disease is one of the most common — and most commonly missed — conditions in South African women. The thyroid gland, a small butterfly-shaped gland at the base of the neck, produces hormones that regulate the metabolism of every single cell in the body. When thyroid function is disrupted, the effects are felt from head to toe — yet the symptoms are so broad and non-specific that thyroid disorders are frequently attributed to stress, ageing or depression before the correct diagnosis is made.
Hypothyroidism — an underactive thyroid — is by far the most common thyroid disorder in women. In South Africa, iodine deficiency historically contributed to thyroid disease, though iodine is now added to table salt. Today, the leading cause of hypothyroidism is Hashimoto’s thyroiditis, an autoimmune condition in which the immune system gradually destroys thyroid tissue. Women are far more susceptible to autoimmune thyroid disease than men, and the risk increases with age, particularly around the menopause transition.
The overlap between hypothyroid symptoms and the normal experience of a busy, stressed woman is part of why the condition is so often missed. Fatigue, brain fog, weight gain, low mood, hair loss, dry skin and constipation are all symptoms that are easily dismissed. Thyroid function testing — at minimum a TSH — is a simple, inexpensive blood test that should be considered in any woman presenting with these symptoms, particularly if she has a family history of thyroid disease or another autoimmune condition.
Thyroid hormones have a profound effect on the reproductive system. Both hypothyroidism and hyperthyroidism can disrupt the menstrual cycle, impair ovulation and reduce fertility. Thyroid disorders in pregnancy carry significant risks — untreated hypothyroidism is associated with miscarriage, premature birth and developmental problems in the baby. The postpartum period is also a high-risk time for thyroid dysfunction, with postpartum thyroiditis affecting up to 10% of women in the first year after delivery.
The relationship between oestrogen and thyroid function adds further complexity for women. Oestrogen stimulates the production of thyroid-binding globulin (TBG), the protein that carries thyroid hormones in the blood. Higher TBG levels mean more thyroid hormone is bound and unavailable — which is why women on oral contraceptives or oestrogen-containing HRT may require higher doses of levothyroxine to maintain adequate free thyroid hormone levels.
If you have been diagnosed with hypothyroidism and are taking levothyroxine but still experiencing symptoms, it is worth discussing free T3 levels with your doctor. Some people convert T4 to T3 poorly, and a small proportion of patients benefit from the addition of T3 (liothyronine) or switching to a combination T4/T3 preparation. HealthLab’s professional directory can help you find an endocrinologist experienced in thyroid management for women.
