TSH Levels During Pregnancy

Iodine Intake
Backed by the Thyroid Association, WHO recommends a daily intake of 250 mcg for pregnant and lactating women.

TSH or Thyroid Stimulating Hormone is responsible for regulating the amount of thyroid hormones released by the body. TSH is produced by a pea-shaped organ called the pituitary gland, which is situated in the brain. If there is a thyroid problem, or the thyroid gland is diseased, it may result in excess or reduced production of thyroid hormone.

These conditions are called hyperthyroidism and hypothyroidism, respectively. Hyperthyroidism speeds up the metabolism of the body, while hypothyroidism slows it down.

During pregnancy, two hormones, estrogen and human chorionic gonadotropin (hCG), are released into the blood. These hormones may increase or decrease the production of TSH levels. hCG hormone is similar to thyroid hormone, and as such, it stimulates the production of thyroid hormone, which, in turn, may have an adverse effect on the body.

The normal levels of TSH hormone in the body are in the range of 0.5 to 5, and anything below or more than this range is something to be concerned about.

Normal TSH Levels

According to experts, the levels of TSH hormone vary during the different stages of pregnancy.

• First Trimester(Less than 2.5 mIU/L)
• Second Trimester(Less than 3 mIU/L)
• Third Trimester(Less than 3 mIU/L)

Hypothyroidism (Low TSH Levels) 
Hypothyroidism is indicated by high TSH levels and low T4 levels. It is a disorder of the immune system, wherein antibodies are produced. These antibodies affect the cells of the thyroid gland, thus, hindering the production of thyroid hormone.

Moreover, the white blood cells may also attack the thyroid gland, thereby, preventing the release of thyroid hormone.This, in turn, decreases the metabolism of the body. This condition can also be caused due to existing hypothyroidism conditions that have not been completely cured.

About 2 to 3% of pregnancies are reported with subclinical hypothyroidism, whereas occurrences of overt hypothyroidism are 0.3 to 0.5%.

Causes

» Autoimmune diseases (most commonly, Hashimoto's disease)
» Radiation therapy
» Swollen thyroid due to infection or cancer
» Surgery
» Low iodine levels
» Certain medications (e.g., amiodarone, lithium)

» Family history
» Accumulation of abnormal substances in cells or tissues (infiltrative diseases)
» Disorders related to hypothalamus

Symptoms
The symptoms develop gradually, and are difficult to notice.

» Dry or flaky skin
» Yellowing around eyes
» Weakness
» Tiredness
» Sensitivity/intolerance to cold
» Constipation
» Hair thinning or hair loss
» Irritability
» Depression
» Sleep disturbance
» Goiter
» Anemia
» Low T4 or high TSH

Diagnosis
The diagnosis of hypothyroidism can be difficult, since the symptoms can often be confused with pregnancy symptoms. The doctor may examine you physically, ask you about the medications you are on, and inquire about the family medical history. Blood tests are done to check the thyroid hormone level.

Risks

The complications that may arise in the mother and the baby are as follows:

Maternal Complications

» Miscarriage
» Anemia
» Myopathy
» Congestive heart failure
» Megacolon
» Preeclampsia
» Adrenal disorders
» Abruption in placenta
» Organic psychosis
» Myxedema coma
» Hyponatremia
» Postpartum hemorrhage

Fetal Complications
» Premature birth
» Low birth weight
» Neonatal respiratory disorder
» Impaired brain development

Treatment
» Levothyroxine, doses of which are gradually increased until TSH levels are back to normal
» Prenatal vitamins

Hyperthyroidism (High TSH Levels)

About 0.2 to 0.4% pregnancies are reported with hyperthyroidism. This condition is usually caused if the mother suffers from Graves' disease. Graves' disease is a disorder of the immune system wherein antibodies are created by the immune system.

These antibodies, in turn, act against healthy tissues and cells of the body. In such a condition, thyroid-stimulating immunoglobulin imitates TSH and releases too much hormone.

Causes
» Graves' disease
» Enlarged or swollen thyroid
» Family history of a thyroid or autoimmune disease
» Gestational transient thyrotoxicosis
» Subacute thyroiditis
» Toxic multinodular goiter
» Single toxic adenoma

» Certain medications (especially those used to maintain the heart rate)
» Infections near the thyroid gland
» High iodine levels
» Struma ovarii (goiter of the ovary)
» Thyrotropin receptor activation

Symptoms
The symptoms of this condition develop gradually, and cannot be noticed immediately. They include:
» Weight loss
» Increased appetite
» Diarrhea
» Constipation
» Heat intolerance

» Excessive sweating
» Bulge in eyes
» Blurred vision
» Painful lump in the neck
» Nervousness
» Fatigue
» Headache
» Insomnia
» Restlessness
» Nausea
» Increased blood pressure
» Muscle weakness
» Tremors or palpitations
» Emotional disturbances

Diagnosis
The diagnosis of hyperthyroidism can be difficult, since the symptoms can often be confused with pregnancy symptoms. However, its diagnosis is done on the basis of high levels of T3 and T4, and low levels of TSH. The doctor may ask you about the medications you are on, and may also inquire about any family history of the condition.

Risks
Following are the complications that may arise due to hyperthyroidism.

Maternal Complications

» High blood pressure
» Severe preeclampsia
» Heart failure
» Premature labor
» Thyroid storm
» Breaking of placenta

Fetal Complications

» Miscarriage
» Neonatal hyperthyroidism
» Low weight at the time of birth
» Intrauterine growth restriction

Treatment
The methods of treating this condition are limited since the health of the baby is at risk. However, the following options are commonly used.

» Antithyroid medications like methimazole, propylthiouracil (PTU), and carbimazole
» Surgery (for those who have adverse reactions to anti-thyroid medications)
» Radioactive iodine (contraindicated)
» Beta blockers like metoprolol and propranolol (to lower the mother's heart rate)

All newborn babies in the United States are tested for hypothyroidism, so as to give them the needed medical attention immediately. However, it is recommended that the TSH levels be checked before, or immediately after the conception.

This measure should especially be followed by women who are at a higher risk of developing the condition, either due to family history or a prior occurrence of the condition.

Disclaimer: This story is for informative purposes only and should not be used as a replacement for professional medical advice.