Worries of Expectant Mothers: When Thyroid Diseases Knock at the Door (Hyperthyroidism)

Pregnant in October, It is the process of waiting for happiness to knock at the door. But in the meantime, Often there are some unexpected visitors, such as this, no, is this group of… thyroid diseases. Thyroid diseases that may occur during pregnancy are various, and can be divided into two categories from the function: hyperthyroidism (hyperthyroidism) and hypothyroidism (hypothyroidism). This issue focuses on hyperthyroidism, hypothyroidism next stage see.

I. Thyroid gland during pregnancy

Before the main character officially takes the stage, let’s briefly introduce the background of the plot: What changes have thyroid gland undergone after entering pregnancy? The main function of thyroid gland is to concentrate iodine in the whole body and process it into thyroxine necessary for human body. In pregnancy, The basal metabolic rate of the body is obviously increased, Thyroid gland has to work overtime to expand production capacity. In order to meet the physiological needs of the mother and the fetus. At this time, Thyroid gland volume will increase by about 10% compared with that before pregnancy, If the supply of iodine as a raw material is insufficient at this moment, For example, pregnant women living in iodine-deficient areas, Thyroid gland volume will increase even more, Up to 20%-40%. Apart from morphological changes, Hormone levels in pregnant women have also changed greatly. Since the beginning of pregnancy, The placenta synthesizes large amounts of human chorionic gonadotropin (hCG), The early pregnancy test paper uses this principle, Pregnancy is judged by testing the content of hCG in urine. One of the important functions of hCG is to simulate the effect of thyroid stimulating hormone (TSH). Stimulate more thyroxine secretion. At the same time, Under the action of elevated estrogen in pregnant women, The level of thyroid binding globulin (TBG) increased significantly, Can also cause thyroxine level to increase. Suddenly there are many strange, unpronounceable professional terms, perhaps some people already feel head big, then directly skip to look at the summary: 1. After pregnancy, especially in the early pregnancy, the changes in the body include: a. Basal metabolic rate increases (specifically manifested as skin temperature increases, fear of heat and hyperhidrosis, eating more easily hungry, heart rate increases, etc.); B. The level of thyroxine increased (mainly TT3 and TT4 increased, FT3 and FT4 slightly increased in the early stage and decreased in the middle and late stages); C. Thyroid stimulating hormone (TSH) level decreases and thyroid gland slightly increases (often indistinguishable by naked eyes)

Second, transient hyperthyroidism syndrome during pregnancy (GTH)

I believe many friends have already seen it, These changes are very similar to [hyperthyroidism]. Even a small number (about 1%-3%) of pregnant women show very obvious manifestations. Will come to the clinic for treatment because of [hyperthyroidism]. Therefore, In their clinical work, The first thing to do, Is to correctly distinguish this is the physiological phenomenon caused by pregnancy, It is also pathological [hyperthyroidism] caused by diseases (such as Graves’ disease). The former is professionally called [transient hyperthyroidism syndrome of pregnancy (GTH)], Belonging to physiological changes, Most of them occur in the early stage of pregnancy, and the symptoms are generally not too serious, which has no great influence on pregnant women and fetuses. Most of them can be relieved by themselves. The treatment is mainly to support symptomatic treatment and does not require the application of antithyroid drugs. 1. Those that meet the following characteristics are likely to be transient hyperthyroidism syndrome during pregnancy, so don’t rush to take drugs: a. Confirmed as [hyperthyroidism]: FT4 and TT4 are elevated, TSH < 0.1 mIU/L; B. No history of hyperthyroidism before pregnancy; C. Thyroid autoantibodies are negative; D there is no obvious goiter and no thyroid ophthalmopathy; E. Occurs in the early stage of pregnancy, sometimes accompanied by hyperemesis, [hyperthyroidism] symptoms are mild, and can gradually ease with the progress of pregnancy.

III. Graves’ Disease during Pregnancy

Four, how to use drugs

At present, there are mainly two kinds of antithyroid drugs: Methimazole (MMI), propylthiouracil (PTU). Compared with MMI, The half-life of PTU is short, the placental pass rate is low, It has little effect on the fetus, Therefore, doctors have long regarded PTU as the first choice for the treatment of hyperthyroidism during pregnancy. However, Recently, more and more studies have found that PTU may cause side effects of drugs such as hepatocyte damage and vasculitis during treatment, and MMI is much safer in this respect. 1. Considering comprehensively, the current consensus on medication is as follows. Please keep in mind for expectant mothers of hyperthyroidism: a. Choose methimazole (MMI) before pregnancy, and replace it with propylthiouracil (PTU) as soon as possible once they enter the pregnancy preparation state; B. Propylthiouracil (PTU) was selected within 12 weeks of pregnancy in the first trimester of pregnancy. C. Stop propylthiouracil (PTU) and switch to methimazole in the middle and late stages of pregnancy. The switching ratio between the two is: 100 mg PTU equals about 10 mg MMI; D in order to avoid the influence of drugs on the fetus during the whole pregnancy, the lowest drug dose should be adopted, not combined with thyroxine, and the control goal is to make FT4 of pregnant women close to or slightly higher than the upper limit of normal value; E. Choose methimazole (MMI) during lactation, which should be taken in batches, and take the medicine just after the baby has finished eating milk. Special emphasis is placed on: drugs are basically safe for the baby’s development, breast milk is precious, please feel free to nurse hyperthyroidism mothers.

Five, adhere to the review

Although expectant mothers are already working very hard, But if you have hyperthyroidism, For the sake of your health and safety and that of your baby, It is also necessary to take pains to carry out regular reexamination. It is generally recommended to check liver function every 4 weeks and FT4 and TSH every 2-6 weeks depending on the disease condition. It should be noted that since FT4 improves quickly and TSH improves slowly after medication, TSH level cannot be used as an observation index for adjusting medication during pregnancy, but if TSH has returned to normal, it is suggested that drugs should be reduced or stopped.

In addition, there is another test index worth recommending: TRAb. Its significance lies in: if it changes from positive to negative, it means that drug therapy can be suspended; If the high level is maintained all the time, the fetal condition must be closely observed from the second trimester of pregnancy, such as monitoring the fetal heart rate, amniotic fluid volume and fetal goiter through ultrasound examination, and screening for neonatal hyperthyroidism after birth.

VI. Summary

The following is a summary of this article:

Don’t worry about hyperthyroidism in pregnancy, and it is most important to distinguish the etiology.

GTH was not treated, Graves needed medication.

The first choice is methyl sulfhydryl to avoid liver damage and methyl sulfhydryl to protect the baby at the beginning of

Don’t think monthly reexamination is frequent, safety depends more on small dose.

I admit that after writing this veteran cadre style, I feel bad all over.