Hyperthyroidism during pregnancy

Hyperthyroidism – what kind of disease is it?

Hyperthyroidism is a disease associated with an excess of hormones produced by the thyroid gland. At the same time, in the most common forms, there is a compensatory decrease in the concentration of TSH, i.e. the hormone responsible for stimulating thyroid function under normal conditions.

Hyperthyroidism in pregnancy – Causes

One of the most common causes of hyperthyroidism in pregnancy is so-called gestational thyrotoxicosis. During pregnancy, especially at the beginning of pregnancy, the concentration of chorionic gonadotropin (beta-hcg), which is similar in structure to TSH, increases. In high concentrations it can cause hyperthyroidism, usually subclinical. In this situation, it is sufficient in most patients to monitor thyroid function somewhat more frequently than in women with normal TSH concentrations; alternatively, symptomatic treatment is given if symptoms are severe. However, gestational thyrotoxicosis can cause vomiting in pregnant women, so determination of free thyroid hormone and TSH levels is indicated if vomiting is uncontrolled. There is a higher risk of subclinical hyperthyroidism in women with multiple pregnancies, where beta-HCG levels are proportionately higher than in singleton pregnancies.

The second most common cause is Graves’ disease, in which the thyroid gland is stimulated to produce hormones by its own abnormal antibodies. This disease requires intensive care by an endocrinology specialist both during and after pregnancy. Pharmacotherapy is also given to most patients.

Hyperthyroidism in pregnancy – symptoms

The symptoms of hyperthyroidism in pregnancy are non-specific. This is due to the fact that during pregnancy, and especially in the first weeks of pregnancy, many symptoms are considered to be those of the first trimester. The symptoms of hyperthyroidism include:

• accelerated heart rate
• Sweating
• shaky hands
• Insomnia
• Weight loss
• increased vomiting

Hypothyroidism in pregnancy – Treatment

Subclinical hyperthyroidism generally does not need to be treated. If, on the other hand, gestational thyrotoxicosis causes symptoms, it is usually treated with propranolol. The more frequent monitoring of thyroid hormones already mentioned is also necessary.

The drugs used for Graves’ disease are thiamazole and propylthiouracil. These drugs are used in the lowest effective doses under the supervision of a gynaecologist and an endocrinologist.

Hyperthyroidism in pregnancy – complications

Excessive hyperthyroidism in pregnancy can have consequences. The most common include premature detachment of the placenta, high blood pressure, pre-eclampsia, miscarriage and premature birth. The disease can also affect the foetus. This can lead to fetal hyperactivity, goitre, tachycardia or growth restriction, which manifests as hypotrophy. Because of the risk of premature birth, the child may also be at risk of complications related to prematurity. For this reason, it is extremely important to monitor thyroid function during pregnancy and to follow the recommendations of the specialists.