Pregnancy brings about hormonal changes within the expecting mother’s body. Some of these alter Thyroid functions as well. These changes have a definite effect on pregnancy and have to be handled with care through tests and often, with medication throughout pregnancy. Regular tests are especially important because Thyroid function tests change during pregnancy. This happens due to the influence of two main hormones: human chorionic gonadotropin (hCG), the hormone that is measured in the pregnancy test and estrogen, the main female hormone.
During pregnancy, the thyroid gland may increase in size but pregnancy-associated goiters are more common in iodine-deficient areas of the world.
Hyperthyroidism and Hypothyroidism may be associated with pregnancy.
Hyperthyroidism during pregnancy
The diagnosis of Hyperthyroidism during pregnancy is difficult because the Thyroid scanning is contraindicated during pregnancy because even smallest amount of radioactivity can be concentrated by the baby’s Thyroid. Hence, gynecologists rely more on a careful study of history, physical examinations and laboratory testing for diagnosis.
The most common cause of Hyperthyroidism during pregnancy is Graves’ disease. Apart from this, very high levels of hCG that shows itself as severe forms of morning sickness may cause passing Hyperthyroidism.
During this period, an inadequately treated Hyperthyroidism can result in early labor and a serious complication known as pre-eclampsia. Also, women with active Graves’ disease during pregnancy have more chances of developing very severe Hyperthyroidism known as the Thyroid Storm.
Hyperthyroidism during pregnancy may be dangerous for the unborn child - fetal tachycardia (fast heart rate), prematurity, stillbirths and possibly congenital malformations can be the results. Extremely high levels of thyroid stimulating immunogloblulins (TSI) can interact with the baby’s Thyroid to cause fetal or neonatal Hyperthyroidism.
Apart from this, if the mother has been prescribed anti-thyroid drugs, the drugs can cross the placenta and potentially impair the baby’s Thyroid function and cause fetal goiter.
Treating Hyperthyroidism during pregnancy
Apart from regular Thyroid stabilizing drugs, Beta-blockers are used at times to help treat significant palpitations and tremors but usually only until the Hyperthyroidism has been brought within control. Surgical removal of the Thyroid gland is rarely recommended in a pregnant woman due to the risks of both surgery and anesthesia to the mother and the baby. But, Radioiodine is ruled out during pregnancy since it readily crosses the placenta and once inside, can cause destruction of the gland and result in permanent Hypothyroidism. However, treating a mother with Hyperthyroidism during pregnancy outweigh the risks if therapy is carefully monitored.
Hypothyroidism during pregnancy
The autoimmune disorder known as Hashimoto’s thyroiditis is by far the most common cause of Hypothyroidism during pregnancy, followed by inadequate or over treatment of a woman already known to have Hypothyroidism from a variety of causes. Unless treated, Hypothyroidism in a pregnant mother can result in maternal anemia (low red blood cell count), myopathy (muscle pain, weakness), congestive heart failure, pre-eclampsia, placental abnormalities, low birth weight infants, and postpartum hemorrhage (bleeding).
Hypothyroidism during pregnancy can also prove fatal to the baby. To begin with, Hypothyroidism in the mother can lead to impaired brain development in the baby. Then, children born with congenital hypothyroidism (no thyroid function at birth) can have severe cognitive, neurological and developmental abnormalities. But, these can largely be prevented if the disease is recognized and treated immediately after birth.
Treating Hypothyroidism during pregnancy
Hypothyroidism in a pregnant woman is handled in the same way as it is handled in a man or a non-pregnant woman; by replacing the Thyroid hormone in the form of synthetic levothyroxine. Doctors recommend that women with known Hypothyroidism should have their thyroid function tested as soon as pregnancy is detected. They also suggest that Thyroid function tests should be taken approximately every 6-8 weeks during pregnancy to ensure that there is normal Thyroid function throughout pregnancy.
