Transient hyperthyroidism during pregnancy

Some women do not have hyperthyroidism before pregnancy, but due to the effect of hormones after pregnancy, they sometimes suffer from hyperthyroidism. In fact, this is a very common phenomenon. However, if hyperthyroidism occurs during pregnancy, it must be treated in time, otherwise it will affect the growth and development of the baby. Many people worry that hyperthyroidism will occur after giving birth. What is the standard for transient hyperthyroidism during pregnancy?

The diagnostic criteria for hyperthyroidism during pregnancy are generally serum TSH < 0.1 mm/L and serum free T4 greater than the upper limit of the pregnancy-specific reference value. By excluding hyperthyroidism syndrome of pregnancy, commonly known as hyperemesis gravidarum, pregnancy complicated by hyperthyroidism can be diagnosed.

Diagnostic criteria for hyperthyroidism during pregnancy

Generally, the basal metabolic rate of normal pregnant women is relatively obvious, and can reach 25% at 4 months of pregnancy. Some symptoms similar to hyperthyroidism will also appear, such as heat intolerance, sweating, hyperphagia, palpitations, etc. Therefore, for hyperthyroidism during pregnancy, the diagnosis of hyperthyroidism can only be made when the metabolic syndrome exceeds the physiological limit of pregnancy, there is exophthalmos, thyroid enlargement accompanied by vascular murmurs, and the basal metabolic rate is above 30%, especially when FT3 and FT4 are elevated.

In addition, the diagnostic criteria for clinical hyperthyroidism during pregnancy are that the patient has a high metabolic syndrome, with serum total thyroxine (TT4) ≥180.6nmol/L (14μg/dl), total triiodothyronine (TT3) ≥3.54nmol/L (230ng/dl), and free thyroxine index (FT4I) ≥12.8. The condition of hyperthyroidism is mild when the maximum TT4 level is <1.4 times the upper limit of normal value, moderate when it is >1.4 times the upper limit of normal value, and severe when there is crisis, hyperthyroid heart disease, heart failure, myopathy, etc.

Definition of pregnancy complicated by hyperthyroidism

Hyperthyroidism is the abbreviation of "hyperthyroidism". It is caused by the thyroid gland synthesizing and releasing too much thyroid hormone, which causes the body's hypermetabolism and sympathetic nerve excitement, resulting in symptoms such as palpitations, sweating, increased eating and bowel movements, and weight loss. Many patients with hyperthyroidism also experience symptoms such as exophthalmos, eyelid edema, and decreased vision. Hyperthyroidism is one of the common endocrine diseases, and it is more common in female patients, especially in women of childbearing age aged 20 to 40.

Pregnancy complicated by hyperthyroidism refers to a woman with hyperthyroidism becoming pregnant or a pregnant woman suffering from hyperthyroidism. Data show that the incidence of hyperthyroidism complicated with pregnancy is 0.5%~2%, the miscarriage rate in hyperthyroidism pregnancy is as high as 26%, and the premature birth rate is 15%.

Transient hyperthyroidism of pregnancy occurs in early pregnancy and naturally relieves in the second and late pregnancy. The symptoms are generally mild and are often accompanied by gastrointestinal symptoms such as loss of appetite, nausea, and vomiting. The thyroid gland is not enlarged and the thyroid autoantibodies are not high. However, the symptoms of true hyperthyroidism are obvious, with gastrointestinal manifestations such as increased appetite, hunger, diarrhea, etc. The thyroid gland is often enlarged, with or without exophthalmos, and the thyroid autoantibodies are often elevated. The symptoms last for a long time and are not easy to relieve, and often require treatment.