Thyroid inflammation (thyroiditis) can occur in the mother during pregnancy or after giving birth (post partum). Most cases are temporary and cause a short-term phase of hyperthyroidism – an overactive thyroid gland. Hypothyroidism – an underactive thyroid gland can also develop during pregnancy as much as one year post partum.
The types of thyroiditis that can affect pregnant women include the following:
- Silent thyroiditis
- Post partum thyroiditis
- Hashimoto’s thyroiditis
- Sub-acute/viral thyroiditis
The term “Silent” as related to thyroiditis, means it is the type that does not cause pain or significant swelling in the thyroid gland as can the painful type called “Sub-Acute” that is often related to viral and respiratory infections. Sub-acute or “viral thyroiditis” can however also occur during pregnancy if the mother contracts a viral illness. The term “post partum” simply means the thyroiditis occurs following pregnancy but if it is not painful, the “Silent” term still applies as well.
Pregnancy places extra physical demands on the mother because her body is nourishing the development of a fetus and this requires more activity by the endocrine glands in the body. These are the glands that supply needed hormones including the thyroid ones that regulate metabolism. The increased demand for more thyroid hormone can result in mild to moderate inflammation in the thyroid gland.
As a result of thyroiditis the immune system will send cells called “anti-inflammatory cytokines” to moderate the inflammation. Hormones such as “cortisol” (cortical) from the adrenal glands will also increase in the body to help reduce inflammation. This process can take several weeks before the thyroiditis resolves. The thyroid gland itself also attempts to override the inflammation and will become overactive (hyperthyroid) for a couple of weeks following the onset of thyroiditis.
When pregnancy triggers thyroiditis, this can also lead to thyroid autoimmunity or permanent autoimmune thyroiditis (Hashimoto’s disease). Temporary types of thyroiditis will usually not cause the mother to test positive for thyroid antibodies or if they are present, they will be found in high-normal or low-positive titers.
Three basic categories of hypothyroidism that can be related to pregnancy are as follows:
- Temporary hypothyroidism
- Permanent hypothyroidism (usually autoimmune)
- Congenital hypothyroidism (Neonatal)
For many pregnant mothers, hypothyroidism is a temporary condition but for others it becomes permanent. Factors that affect the term of hypothyroidism that develops, include genetic tendency toward thyroid disease, meaning it is passed down through one or both parents and the presence of other endocrine disorders such as diabetes which can also increase the risk for permanent hypothyroidism.
When a baby is born with hypothyroidism, it is referred to as “Congenital Hypothyroidism” and in most cases, is a temporary condition. This, points to the importance in blood testing or what is also called “Newborn Screenings”. Treatment for hypothyroidism must be administered in newborns to prevent immature development that can affect them mentally and/or physically.
Pregnant mothers with thyroid autoimmunity can experiencing high levels of auto-antibodies from the immune system that cause inflammation and damage to the gland. This places them at increased risk for experiencing a miscarriage or having a baby born with birth defects.
If thyroid autoimmunity is discovered prior to pregnancy, mothers wishing to conceive will first be given treatment to reduce the antibody levels and to treat any thyroid hormone imbalance. This will usually require several months of follow-up blood retesting before patients are ready to safely conceive as determined by their doctor.
Thyroiditis usually resolves on its own without the need for prescription drugs to control inflammation. Over-the-counter anti-inflammatory drugs (excluding aspirin during pregnancy) are usually all that are necessary, along with sufficient fluid intake and bed rest. If thyroiditis is severe and difficult to resolve, a treating doctor might prescribe an anti-inflammatory steroid called a “corticosteroid” but this treatment would likely be restricted to post partum cases.
Hypothyroidism in either the mother or baby is treated by replacing the low thyroid hormone by oral or intravenous dosing. Temporary hypothyroidism will resolve after several weeks of a patient receiving a dose of replacement thyroid hormone while the permanent type will require this as a lifelong treatment.