Thyroid During Pregnancy

Located in the front of your neck, the thyroid is a butterfly-shaped gland, which is usually no longer than 2 inches with an overall weight of 1 ounce. Its main function is to regulate metabolism and determine how your body uses energy. Too much or too little thyroid hormone can affect every organ in the body. Just like other hormonal changes taking place during pregnancy, you may also notice a change in thyroid during pregnancy. How does it affect your body and what can you do to keep things under control? Let's find out now.

Normal Thyroid Changes During Pregnancy

The fetus relies heavily on the mother's supply of thyroid hormone during the first trimester, and baby's thyroid only becomes active at around 12 weeks. Here are 2 main changes of the thyroid during pregnancy:

  • Thyroid hormone levels normally go up during pregnancy due to two main hormones – estrogen and human chorionic gonadotrophin (hCG). And the placenta makes hCG that stimulates your thyroid gland to increase the levels of thyroid hormone in the blood. At the same time, increased estrogen in pregnancy produces higher levels of a protein called thyroid-binding globulin that transports thyroid hormone in the blood.
  • What's more, it is important to note that the thyroid gland may normally enlarge a bit during pregnancy, but it is usually not large enough to be noticed during a physical exam. You may have a thyroid disease if you have a noticeably enlarged gland.

Without normal levels of thyroid hormone, normal development of the baby's nervous system and brain is not possible. Although due to the abovementioned normal changes, it is sometimes difficult to tell whether the thyroid during pregnancy is functioning normally, symptoms like increased gland size or fatigue and certain tests may still help get to a conclusion.

Hyperthyroidism During Pregnancy

Hyperthyroidism means your body is producing way too much of thyroid hormone and this will lead to several problems.

1. Symptoms

Enlarged thyroid, increased levels of thyroid hormone in bloodstream, nausea, vomiting, fatigue, heat tolerance and increased heart rate are some typical symptoms of hyperthyroidism. You may also notice changes in appetite, poor eyesight, increased perspiration, abdominal discomfort or increase in blood sugar levels.

If left untreated, hyperthyroidism in pregnancy can lead to several complications. The most common problems are congestive heart failure, miscarriage, low birth weight, premature birth and severe elevation in blood pressure, especially during the last month of pregnancy.

2. Treatment

Thyroid hormone tends to be higher during pregnancy, so mild overactive thyroid during pregnancy may not need any treatment. If treatment is needed, here are the options:

  • Anti-thyroid medications

Anti-thyroid medications are most commonly used and are effective for a little bit more severe cases. These medications interfere with thyroid hormone production and can pass through the placenta in small amounts. So, it can reduce thyroid hormone production in fetus.

In the United States, doctors usually prescribe methimazole for most types of hyperthyroidism, but it should be avoided during the first trimester and doctors usually start with the lowest possible dose to avoid harming the baby. And propylthiouracil (PTU), another anti-thyroid medication, is usually a better choice during first trimester.

Anti-thyroid medications can be stopped in the last 4-8 weeks of pregnancy if the thyroid hormone level returns to normal but continuous monitor for recurrence or other thyroid problems after delivery is needed. Side effects may include allergic reactions like itching and rashes, decreased white blood cell, vulnerable to infections and even liver failure may happen.

  • Other options

In rare cases, you may have to undergo surgery that involves removing all or part of the gland. But never use radioactive iodine to treat hyperthyroidism during pregnancy because it will damage your baby's thyroid gland.

Hypothyroidism During Pregnancy

Hypothyroidism actually means that your body is producing way too less thyroid hormone and this can lead to several complications.

1. Symptoms

Hypothyroidism is quite common but usually goes undetected due to its mild symptoms which often make it look like depression. The common symptoms include tightening of skin, slow pulse, extreme fatigue, puffy and swollen face, weight gain, cold intolerance, abdominal discomfort, cramps and lack of concentration. 

When left untreated, hypothyroidism can cause several complications, including stillbirth, low birth weight, miscarriage and anemia. Uncontrolled hypothyroidism may prove quite harmful for your baby's brain and nervous system.

2. Treatment

Since hypothyroidism can be really harmful to you and your baby, you have to take various measures to clear it up.

  • Take thyroxine

The best treatment option to treat inactive thyroid during pregnancy is to take synthetic thyroid hormone called thyroxine, which is quite similar to the T4 made by the thyroid gland. If you have been taking thyroxine before pregnancy, you will have to increase your dose during pregnancy. It is important to monitor thyroid function and you have to go for a checkup every 6-8 weeks during your pregnancy.

  • Eat well-balanced diet

Paying attention to your diet is never more important than it is during pregnancy, especially when you have hypothyroidism. You need to work with your dietician to stick to a balanced-diet to get enough prenatal mineral and multivitamin and maintain better thyroid health.

Try eat low-fat and unsweetened foods. For example, you should eat more vegetables like carrots, pumpkin, kale and tomato, fruits like cantaloupe, mango, banana, apricot and orange, and dairy like low-fat yogurt or milk, etc.

  • Increase iodine intake

You can take dietary supplements to increase your intake of iodine, which is required by the thyroid to make thyroid hormone and by the normal development of your baby. Therefore, you need to take at least 250 micrograms of iodine a day. Similarly, choosing iodized salt will also help meet your requirements of iodine during pregnancy. Do not increase your iodine intake without consulting your doctor, especially if you have autoimmune thyroid diseases.

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