Thyroid diseases and pregnancy

Q: Will my hypothyroidism go way after my first pregnancy?

Krishna: Thyroid disease is a group of disorders that affects the thyroid gland. The thyroid is a small, butterfly-shaped gland in the front of your neck that makes thyroid hormones. Thyroid hormones control how your body uses energy, so they affect the way nearly every organ in your body works—even the way your heart beats.

Sometimes the thyroid makes too much or too little of these hormones. Too much thyroid hormone is called hyperthyroidism and can cause many of your body’s functions to speed up. “Hyper” means the thyroid is overactive. Learn more about hyperthyroidism in pregnancy. Too little thyroid hormone is called hypothyroidism and can cause many of your body’s functions to slow down. “Hypo” means the thyroid is underactive.
Hypothyroidism, also called underactive thyroid, is when the thyroid gland doesn’t make enough thyroid hormones to meet your body’s needs.  Thyroid hormones control the way your body uses energy, so they affect nearly every organ in your body, even the way your heart beats. Without enough thyroid hormones, many of your body’s functions slow down.
Left untreated, hypothyroidism during pregnancy can affect both mother and baby. However, thyroid medicines can help prevent problems and are safe to take during pregnancy. Many women taking thyroid hormone medicine need a higher dose during pregnancy.
Hypothyroidism has many symptoms that can vary from person to person. Some common symptoms of hypothyroidism include fatigue, weight gain, trouble tolerating cold, joint and muscle pain, dry skin or dry eyes, thinning hair, heavy or irregular menstrual periods or fertility problems, slowed heart rate, and even depression.

Three types of thyroiditis can cause thyrotoxicosis followed by hypothyroidism.

Subacute thyroiditis involves a painfully inflamed and enlarged thyroid.

Postpartum thyroiditis develops after a woman gives birth.

Silent thyroiditis is painless, even though your thyroid may be enlarged.

Experts think it is probably an autoimmune condition. Symptoms of an underactive thyroid are often the same for pregnant women as for other people with hypothyroidism. Symptoms include extreme tiredness, trouble dealing with cold, muscle cramps, severe constipation, problems with memory or concentration.

Hypothyroidism in pregnancy is usually caused by Hashimoto’s disease and occurs in 2 to 3 out of every 100 pregnancies. Hashimoto’s disease is an autoimmune disorder. In Hashimoto’s disease, the immune system makes antibodies that attack the thyroid, causing inflammation and damage that make it less able to make thyroid hormones.
Untreated hypothyroidism during pregnancy can lead topreeclampsia—a dangerous rise in blood pressure in late pregnancy, anemia, miscarriage, low birthweight, stillbirth, congestive heart failure.

These problems occur most often with severe hypothyroidism.Because thyroid hormones are so important to your baby’s brain and nervous system development, untreated hypothyroidism—especially during the first trimester—can cause low IQ and problems with normal development.

Treatment for hypothyroidism involves replacing the hormone that your own thyroid can no longer make. Your doctor will most likely prescribe levothyroxine NIH external link, a thyroid hormone medicine that is the same as T4, one of the hormones the thyroid normally makes. Levothyroxine is safe for your baby and especially important until your baby can make his or her own thyroid hormone.

Your thyroid makes a second type of hormone, T3. Early in pregnancy, T3 can’t enter your baby’s brain like T4 can. Instead, any T3 that your baby’s brain needs is made from T4. T3 is included in a lot of thyroid medicines made with animal thyroid, such as Armour Thyroid, but is not useful for your baby’s brain development. These medicines contain too much T3 and not enough T4, and should not be used during pregnancy. Experts recommend only using levothyroxine (T4) while you’re pregnant.Some women with subclinical hypothyroidism—a mild form of the disease with no clear symptoms—may not need treatment.

Postpartum thyroiditis is an inflammation of the thyroid that affects about 1 in 20 women during the first year after giving birth and is more common in women with type 1 diabetes. The inflammation causes stored thyroid hormone to leak out of your thyroid gland. At first, the leakage raises the hormone levels in your blood, leading to hyperthyroidism. The hyperthyroidism may last up to 3 months. After that, some damage to your thyroid may cause it to become underactive.

Your hypothyroidism may last up to a year after your baby is born. However, in some women, hypothyroidism doesn’t go away. Not all women who have postpartum thyroiditis go through both phases. Some only go through the hyperthyroid phase, and some only the hypothyroid phase.

So you need treatment from medical professionals.

If you had hypothyroidism before you became pregnant and are taking levothyroxine, you will probably need to increase your dose. Most thyroid specialists recommend taking two extra doses of thyroid medicine per week, starting right away.

Contact your doctor as soon as you know you’re pregnant.

Because the thyroid uses iodine to make thyroid hormone, iodine is an important mineral for you while you’re pregnant. During pregnancy, your baby gets iodine from your diet. You’ll need more iodine when you’re pregnant—about 250 micrograms a day. Good sources of iodine are dairy foods, seafood, eggs, meat, poultry, and iodized salt—salt with added iodine. Experts recommend taking a prenatal vitamin with 150 micrograms of iodine to make sure you’re getting enough, especially if you don’t use iodized salt.1 You also need more iodine while you’re breastfeeding since your baby gets iodine from breast milk. However, too much iodine from supplements such as seaweed can cause thyroid problems.

Sources:

1.  https://www.niddk.nih.gov/health-information/endocrine-diseases/pre...
2. https://www.niddk.nih.gov/health-information/endocrine-diseases/....

(Please note that this answer is just for information purpose only. You need to consult a qualified medical doctor to treat any health issues you face).