Is hyperthyroidism in pregnant women dangerous?

This is an automatically translated article.

The article was professionally consulted with General Internal Medicine Doctor - Department of Examination & Internal Medicine - Vinmec Nha Trang International General Hospital.
Is hyperthyroidism in pregnant women dangerous? This is a question asked by many pregnant women. Hyperthyroidism during pregnancy affects both mother and baby. In addition, some treatment methods should be noted for pregnant women with hyperthyroidism.

1. What is hyperthyroidism?

Hyperthyroidism is an immune system disorder that leads to an overactive thyroid gland, leading to increased production of thyroid hormone into the bloodstream, causing metabolic disorders of the body.
Hyperthyroidism is the second most common endocrine disease after diabetes with a prevalence of 1 in 1,500 in pregnant women. Because thyroid hormones affect a number of different body systems, signs and symptoms involve different organs. Pregnant women with hyperthyroidism often have symptoms such as irregular weight gain, heart palpitations, abnormal vomiting...
The main treatment goal is to inhibit the overproduction of thyroid hormone and reduce the level of thyroid hormone. severity of symptoms.

2. Causes of pregnancy hyperthyroidism

Basedow is the most common cause of hyperthyroidism (80-85%), occurring in 1/1500 pregnant women. In addition, some cases of HCG too high also cause symptoms of hyperthyroidism. Diagnosis of Graves during pregnancy is more difficult because emotional symptoms, fear of heat, hot and humid skin, and sweating are easily confused with symptoms of morning sickness. Iodine concentration test cannot do because it will affect the fetus. Therefore, the diagnosis is based on history, tachycardia above 100 beats/min, echocardiography of enlarged, diffuse thyroid gland, TSH, FT4, TRAb tests. The hormone HCG is produced during pregnancy, which peaks around 12 weeks into pregnancy. This causes mild irritation of the thyroid gland and causes some symptoms of hyperthyroidism. If you're carrying multiples, your HCG levels will rise even higher and symptoms will become more pronounced. About 10-20% of pregnant women develop these symptoms, but most do not need treatment. Women with severe morning sickness (hyperemesis gravidarum) may also have mild symptoms of hyperthyroidism. However, these symptoms usually go away after the first trimester.

In addition to the above, there can also be the following:
Immune disorders, such as Graves' disease, can cause the thyroid gland to overproduce hormones. A family history of thyroid problems or autoimmune diseases can also increase your risk of developing hyperthyroidism during pregnancy. Certain medications, such as those that help the heart beat normally, can also cause hyperthyroidism during pregnancy. An infection near the thyroid gland can also be a cause. Other thyroid problems such as an enlarged thyroid, swelling from an infection, or thyroid cancer can also affect how the thyroid gland works. High iodine levels can also cause hyperthyroidism. The thyroid gland uses iodine to make hormones. Therefore, the thyroid gland will make more hormone if the iodine level in your body is high.

3. Symptoms of Hyperthyroidism in Pregnancy

Weight loss or not gaining weight as expected, frequent cravings, diarrhea or constipation Tachycardia and rapid breathing, even at rest Increased sweating and poor heat tolerance U, painful swelling in the neck or bulging eyes

Anxiety, restlessness, fatigue or trouble sleeping Tremors and muscle weakness High blood pressure, headaches, nausea and blurred vision Thyroid may change in size during pregnancy

4. How does hyperthyroidism affect pregnancy?

About 1% of babies born to women with Graves' disease will develop hyperthyroidism after birth. This is because thyroid-stimulating antibodies can be passed through the placenta and affect the baby. Before birth, if the fetal heart rate is high (greater than 160 beats/min), when ultrasound shows the presence of goiter in the fetus, poor fetal growth or abnormal bone growth, it may be a sign of pregnancy. found that the fetus has hyperthyroidism. If this is the case, your doctor may prescribe medication (PTU or MMI) to treat your unborn baby. After birth, hyperthyroidism can be detected by blood tests. Graves' disease can occur during the first trimester of pregnancy or in women who have had Graves before. In addition to the classic symptoms, the mother may also have preterm labor or preeclampsia. In addition, the mother will be at high risk of heart failure, acute thyrotoxicosis. Basedow's disease may improve in the third trimester of pregnancy or may also worsen in the postpartum period.

Hyperthyroidism that is not well controlled: Leads to congenital heart defects, fetal growth retardation, premature birth, stillbirth and possibly birth defects. That's why it's so important to treat hyperthyroidism in pregnant women. TSI (thyroid stimulating hormone) too high: Basedow is known as an autoimmune disease, the body produces thyroid-stimulating antibodies (TSI). This antibody crosses the placenta and can affect the fetal thyroid gland causing neonatal hyperthyroidism.

5. Treatment options for women with gestational hyperthyroidism?

Mild hyperthyroidism (poor symptoms, slightly elevated hormone levels) will usually be followed closely without any treatment for both mother and baby after birth. When severe hyperthyroidism requires treatment, a synthetic antithyroid drug should be selected as PTU and closely monitored (monthly TSH test, thyroid hormone) to avoid hypothyroidism for the mother and child. In women who cannot be treated with synthetic antithyroid drugs (drug allergies), surgery may also be an option. However, thyroidectomy should be considered very closely because of the high risk in anesthesia and surgery for both mother and fetus. Surgery may be done to remove all or part of the thyroid gland. Your doctor will perform surgery during pregnancy if they feel that it is safe for you and your baby.

Radioiodine treatment is contraindicated for pregnant women because radioactive iodine crosses the placenta causing loss of thyroid function in children. Beta-blockers can be used to relieve symptoms of palpitations and tremors caused by hyperthyroidism. Small doses are recommended, which are usually needed until hyperthyroidism is controlled with synthetic antithyroid drugs. Usually, women with Graves' disease after giving birth will get worse (usually in the first 3 months after giving birth), so it is necessary to increase the dose of antithyroid drugs during this time. At the same time, it is necessary to strictly control thyroid function. The baby can be breastfed if the mother is treated with PTU because PTU is highly protein bound and passes through breast milk less than other drugs. Usually, drugs such as propylthiouracil (PTU) and methimazole (MMI) will be used. However, both drugs can cross the placenta and enter the fetus. However, treatment will be a priority because if left untreated, it can lead to more unpredictable consequences. Women with hyperthyroidism treated with PTUs and MMIs can breastfeed.. PTUs are usually preferred because they are found in lower concentrations in breast milk. Should be treated with low dose, maintaining FT4 in the upper limit of normal will be better for the fetus. During the course of treatment, the fetus is regularly monitored for growth rate, fetal heart rate, and ultrasound for fetal goiter. The Department of Endocrinology - Vinmec International General Hospital is one of the specialties in the field of internal medicine that undertakes examination, diagnosis and treatment with the nature of long-term monitoring of chronic diseases related to disorders. function of the endocrine system.
In which, hyperthyroidism in pregnant women is closely coordinated between the two specialties, endocrinology and obstetrics, with modern equipment and machinery to bring efficiency in diagnosis and treatment. Closely monitor the unwanted effects, then find the appropriate treatment to limit the effects of hyperthyroidism for mother and baby.
Specializes in applying new techniques in disease treatment: Treating benign thyroid nodules with high-frequency ablation (avoiding thyroid surgery for patients). Especially, there is a team of well-trained and experienced medical doctors:
Associate Professor, Doctor, Doctor Nguyen Thi Hoan Associate Professor, Doctor, Doctor Chu Hoang Van Doctor, Doctor Pham Thi Hong Hoa Master, Doctor Pham Thi Thu Huong Master, Doctor Bui Minh Duc
Master, Doctor Nguyen Thi Cam Tu Doctor Nguyen Ngoc Son

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