What should you pay attention to if serum thyroid-stimulating hormone is high during pregnancy?

During pregnancy, the pregnant woman's body functions decline, which can easily lead to physical illness. In addition, the growing fetus continuously absorbs nutrients from the mother, so the pregnant woman will have many physical problems. High serum thyroid-stimulating hormone during pregnancy is a common disease among pregnant women, which can cause fatigue or physical discomfort. So what is the reason for high serum thyroid-stimulating hormone during pregnancy?

Serum thyroid-stimulating hormone (TSH) is one of the major hormones produced by the anterior pituitary gland. Due to the close negative feedback relationship between serum TSH level and serum T4, TSH has become an important first-line indicator for diagnosing hyperthyroidism (hyperthyroidism) and hypothyroidism (hypothyroidism).

Clinical significance

The combined use of serum thyroid hormone and TSH can determine the cause of thyroid dysfunction and help develop an effective treatment plan.

1. Elevated thyroid hormone accompanied by decreased TSH is mostly primary hyperthyroidism caused by diseases of the thyroid gland itself, such as diffuse goiter, thyroid adenoma, etc. When thyroid hormones and TSH levels are elevated, it is usually secondary hyperthyroidism caused by hypothalamic-pituitary dysfunction, such as pituitary adenoma.

2. Decreased thyroid hormone accompanied by increased TSH is mostly caused by primary thyroid dysfunction, such as excessive treatment of primary hyperthyroidism and chronic thyroiditis. Serum thyroid hormone and TSH are both decreased, which is mostly secondary hypothyroidism caused by impaired hypothalamic-pituitary function.

Take hyperthyroidism as an example. The human endocrine system is very complex. The hormones secreted by various organs influence each other and jointly regulate the body's homeostasis. As the center of endocrine regulation in the human body, the hypothalamus can secrete thyrotropin-releasing hormone (TRH), which acts on the pituitary gland to promote the secretion of thyroid-stimulating hormone (TSH). TSH acts on the thyroid gland, promoting the secretion of thyroid hormones and the proliferation of the gland. At the same time, excessive thyroid hormone in the body will also have a feedback inhibitory effect on the secretion of TRH and TSH, which is the hypothalamus-pituitary-thyroid axis of the endocrine system.

When hyperthyroidism occurs in the human body, the thyroid hormone (T3, T4) increases, which can feedback inhibit the gland from producing and releasing thyroid stimulating hormone (TSH). Therefore, the TSH content in serum will decrease at this time. Even changes in TSH are more sensitive than those of T3 and T4. For example, subclinical hyperthyroidism refers to a serum TSH level below the lower limit of normal, while T3 and T4 are within the normal range, with no or mild hyperthyroidism symptoms. From this, the important guiding role of TSH in clinical practice is evident.