Does taking thyroid medication affect the fetus?

Taking thyroid medication has an effect on the fetus is not a common concern of many mothers who find out that they are pregnant while undergoing thyroid treatment. Although studies show that thyroid medication has little effect on the fetus, however, to ensure safety, usually pregnant women are prescribed thyroid medication with the lowest dose. When taking the drug, mother and baby also need to be closely monitored throughout pregnancy.

During pregnancy, if the mother has hypothyroidism or hyperthyroidism, both affect the health of the mother and the development of the fetus. Therefore, to ensure a healthy birth, women of childbearing age are advised to have thyroid problems treated before becoming pregnant.
The mother may have hypothyroidism before pregnancy due to autoimmune thyroiditis but not known or not thoroughly treated. Or due to treatment of hyperthyroidism (with methods such as surgical removal, radioactive iodine, thyroid medication - high-dose synthetic antithyroid drugs) can also lead to hypothyroidism during pregnancy. Having hypothyroidism in a previous pregnancy can also continue to occur in subsequent pregnancies.
Meanwhile, pregnancy can cause hyperthyroidism in the mother, due to changes in hormones and the size of the thyroid gland.

The following thyroid medications are known to treat hypothyroidism and hyperthyroidism in pregnant women:
Hypothyroidism: Synthetic thyroid hormone drugs, eg levothyroxine. This medication is used to treat hypothyroidism in both men and non-pregnant women. For pregnant women, the dose can be increased by about 25 - 50%.
Hyperthyroidism: Synthetic antithyroid drugs, eg carbimazol, methimazole, methylthiouracil (MTU), propylthiouracil (PTU), thyrozol. Most of these synthetic antithyroid drugs cause side effects on the fetus, one of which is hypothyroidism in the fetus. However, in these synthetic thyroid medications, PTU and thyrozole are recommended because of the low incidence of adverse effects on the fetus.
In addition, beta blockers are also used to help relieve some of the symptoms of the disease. However, taking the drug can enter the fetus and affect the development of the fetus, causing the baby to be born with low birth weight. Therefore, the drug is only used when absolutely necessary.

If detecting hypothyroidism or hyperthyroidism during pregnancy, the mother avoids being too worried, instead can rest assured to take the drug as prescribed by the doctor, and closely monitor the mother's health and little. Here are some notes when taking thyroid medication during pregnancy:
For hypothyroidism: When taking the thyroid hormone drug levothyroxine to treat hypothyroidism, the mother should pay attention to check the thyroid function about approx. Every 6-8 weeks, if the dose is changed, then after 4 weeks.
After giving birth, take the drug at the same dose as when not pregnant. The multivitamin drugs added during pregnancy can reduce the absorption of hypothyroid drugs, so the mother should be careful to take the drugs about 2-3 hours apart.
For hyperthyroidism: PTU and thyrozole are 2 drugs that treat thyroid - synthetic antithyroid drugs are preferred for use in the treatment of severe hyperthyroidism. However, it is necessary to pay attention to the treatment with the lowest dose, and at the same time, the mother and the baby should be closely monitored for signs such as fetal heart rate, fetal development and ultrasound to promptly detect possible goiter. present in the fetus or not.