What is Postpartum Thyroiditis?
Postpartum thyroiditis (PPT) is a condition affecting the thyroid gland that can come up within the first year following the birth of a child, especially when the woman has not had thyroid problems before pregnancy. This condition is linked to one’s immune system and can lead to temporary or permanent thyroid problems.
Postpartum thyroiditis usually shows itself in one of three ways: first, temporarily overactive thyroid (hyperthyroidism) seen in around 32% of patients; second, temporarily underactive thyroid (hypothyroidism) seen in about 43% of patients; and third, a brief period of an overactive thyroid followed by an underactive one, then recovery— this is the typical process of PPT, seen in 25% of patients.
Tied to the immune system, postpartum thyroiditis is linked with the presence of specific immune proteins called thyroid peroxidase (TPO) antibodies. If these antibodies are detected in a woman’s early pregnancy, there is a 30% to 52% chance that she might experience postpartum thyroiditis. This condition could also occur after a miscarriage between 5 to 20 weeks into the pregnancy.
During pregnancy, levels of TPO antibodies naturally decrease as the body suppresses the immune system to protect the growing fetus. However, women whose TPO antibodies are still detectable in the later stages of pregnancy have an 80% risk of developing postpartum thyroiditis.
For these reasons, medical guidelines from the Endocrine Society suggest screening women who are at high risk of developing postpartum thyroiditis. This includes those with preceding postpartum thyroiditis, a positive TPO antibody test, or type 1 diabetes. These women are recommended to have their serum TSH levels checked three and six months after delivering the baby to ensure thyroid functionality.
What Causes Postpartum Thyroiditis?
Postpartum thyroiditis is a disease that can affect your thyroid after childbirth and is linked to the body’s immune system. It’s connected with the presence of certain antibodies, known as thyroid peroxidase (TPO) antibodies, that can damage the thyroid.
This condition is also known as ‘destructive thyroiditis’ because it involves a type of white blood cell, lymphocytes, infiltrating and harming the thyroid gland. The damage seen in postpartum thyroiditis is similar to another thyroid disease called Hashimoto thyroiditis. Both of these conditions are believed to have some genetic factors, especially related to two groups of genes, known as HLA-D and HLA-B. These findings suggest that the risk of developing these diseases can be inherited.
Similar to postpartum thyroiditis, the presence of TPO antibodies is also found in other immune system-related thyroid conditions such as Graves’ disease and Hashimoto thyroiditis. These antibodies are a telltale sign of the level of damage by lymphocytes within thyroid gland. TPO antibodies can trigger other immune cells to cause more damage, deepening the harm to the thyroid.
Risk Factors and Frequency for Postpartum Thyroiditis
Postpartum thyroiditis (PPT), a condition affecting the thyroid gland after childbirth, is fairly common. It is reported to occur in about 8% pregnancies, while the frequency varies between 1.1% and 16.7%. However, this percentage can change due to various factors such as how long after childbirth the person was checked, and the iodine levels in their body. For instance, in Thailand, where iodine intake is generally low, the rate is around 1.1%. On the other hand, in similar conditions, Brazil reports a rate of 13.3%.
People in high-risk groups are more likely to develop postpartum thyroiditis. These groups include those with type 1 diabetes and those with a family history of thyroid disorders, with reported rates of 19.1% and 20.0% respectively. Furthermore, if someone has had postpartum thyroiditis in the past, they have a 42.4% chance of experiencing it again with each subsequent pregnancy.
- The prevalence of postpartum thyroiditis (PPT) is 8%, and it happens in between 1.1% and 16.7% of pregnancies.
- The rates can differ depending on factors like how long a person was followed up after giving birth, and their iodine levels.
- In areas with low iodine intake such as Thailand and Brazil, the rates of PPT are 1.1% and 13.3% respectively.
- The prevalence of PPT in high-risk groups, such as those with type 1 diabetes or a family history of thyroid problems, is reported at 19.1% and 20.0% respectively.
- For anyone who has previously had PPT, there’s a 42.4% chance it will happen again in subsequent pregnancies.
Signs and Symptoms of Postpartum Thyroiditis
Postpartum thyroiditis is a condition that doesn’t cause pain. In other words, it’s painless. A lot of people who have this condition do not experience symptoms, or may only have mild symptoms when in a state of thyrotoxicosis, which means there is too much thyroid hormone. These may include feeling irritable, having a racing heart, feeling tired, and being intolerant to heat.
When the condition enters the hypothyroid state, meaning there are too few thyroid hormones, symptoms appear more commonly. At this stage, sufferers could notice constipation, dry skin, fatigue, difficulty concentrating, intolerance to cold, and tingling sensations. Research has shown that people with postpartum thyroiditis and positive TPO antibodies tend to have more severe symptoms than those without these antibodies.
- Frustration or irritability
- Rapid heartbeat
- Fatigue
- Inability to tolerate heat
- Constipation
- Dry skin
- Difficulty concentrating
- Intolerance to cold
- Tingling sensations
Testing for Postpartum Thyroiditis
Postpartum thyroiditis, a condition affecting the thyroid gland after pregnancy, is diagnosed based on symptoms and certain blood tests. The blood tests measure the levels of Thyroid-Stimulating Hormone (TSH) and free T4, a type of thyroid hormone.
Patients with postpartum thyroiditis show similar test results to those with a condition known as painless thyroiditis. During the hyperthyroid phase, where the thyroid is overactive, the levels of free T4 and T3 (another thyroid hormone) might be high or at the upper limit of normal, while TSH levels can be low. This phase could be mild or severe (described as “subclinical” or “overt” in medical terms).
Some patients move from a hyperthyroid state (where the gland is producing too many hormones) to a hypothyroid state (where it’s not producing enough). During this transition, the T4 levels might become low days or weeks before the TSH level rises above the normal range. This is because the earlier phase of hyperthyroidism had suppressed the TSH levels.
About 60 to 85 percent of patients with postpartum thyroiditis have high levels of anti-thyroid peroxidase antibodies. These antibodies are at their highest when the patient is in the hypothyroid state or shortly after that phase. In addition, some patients may also have a slight increase in C-reactive protein and/or erythrocyte sedimentation rate, indicating inflammation in the body.
It’s important for doctors looking after women after childbirth to be aware of the possibility of postpartum thyroid dysfunction. This condition can cause various symptoms during the postpartum period (the time after giving birth).
Treatment Options for Postpartum Thyroiditis
A study analyzing 605 pregnant women and women who recently gave birth found that none of the women experiencing an overactive thyroid (thyrotoxicosis) and 40% of women with an underactive thyroid (hypothyroidism) required treatment. When treatment was necessary, it typically lasted for about a year, while long-term treatment was only required in up to 20% of cases that developed thyroid inflammation after childbirth (postpartum thyroiditis). There have been no studies to determine the best timing and methods for treating postpartum thyroiditis.
The treatment for an overactive thyroid after childbirth is based on the fact that this condition is typically temporary. Anti-thyroid medications, like methimazole and propylthiouracil, are usually ineffective because this condition doesn’t increase the production of thyroid hormones. Most symptoms are usually mild. However, significant symptoms in some cases can be eased with a low dose of propranolol, a type of medication that reduces heart rate and blood pressure.
It’s important to note that this condition must be distinguished from Graves’ disease, which is another cause of an overactive thyroid. Once the overactive thyroid state resolves, a blood test measuring thyroid stimulating hormone (TSH) should be performed within four to eight weeks (or sooner if new symptoms develop) to screen for an underactive thyroid.
In people with significant symptoms, those that are breastfeeding, or those who want to become pregnant, treatment should be started. Treatment with levothyroxine, a medication that replaces or provides more thyroid hormone, is often considered in postpartum thyroiditis patients who have mild symptoms or who want to become pregnant again. If treatment is not started immediately, the doctor will check thyroid function every four to eight weeks until their thyroid levels become normal.
It’s important that these women use contraception and avoid getting pregnant before their thyroid levels normalize. While the length of time necessary to take levothyroxine hasn’t been studied, it’s important to maintain normal thyroid levels in people who are pregnant or want to become pregnant. It’s possible to start reducing the levothyroxine dose 12 months after childbirth to see if the underactive thyroid state is temporary or permanent, but this has to be done gradually. Also, blood tests to measure TSH levels should be performed every six to eight weeks during this tapering process.
What else can Postpartum Thyroiditis be?
The conditions listed below are usually considered when diagnosing similar symptoms:
- Graves disease
- Hashimoto thyroiditis
- Postpartum mood disorder
What to expect with Postpartum Thyroiditis
The health progression of postpartum thyroiditis, which is a condition that can affect some women after giving birth, can vary from case to case. In this context, ‘postpartum’ means after childbirth and ‘thyroiditis’ refers to inflammation of the thyroid gland. The thyroid is a small organ in your neck that helps control your metabolism – how your body uses energy.
Interestingly, only about 30% of women who experience this condition will continue to have an underactive thyroid (hypothyroid state), a year after they have given birth.
Possible Complications When Diagnosed with Postpartum Thyroiditis
In many cases of postpartum thyroiditis, a condition affecting the thyroid after childbirth, thyroid function typically resumes a normal state within 12 to 18 months from when symptoms first appear. However, some people do not recover from the low-thyroid stage and may develop chronic hypothyroidism, a long-term condition where the thyroid doesn’t produce enough hormones.
Potential Outcomes:
- Resuming normal thyroid function within 12 to 18 months of the onset of symptoms.
- Developing permanent hypothyroidism if recovery from the low-thyroid phase does not occur.
Preventing Postpartum Thyroiditis
Postpartum thyroiditis, a condition that affects the thyroid after childbirth, is unfortunately not something that can be prevented. Patients, especially those who are at greater risk of developing this condition, should make sure to discuss any symptoms with their primary care doctor or obstetrician. It’s important not to assume that these symptoms are simply due to the stress of looking after a newborn baby.