Postpartum Hypothyroidism

After giving birth, the mother’s body needs to start some changes to come back to the initial stage where she was supporting only her own body. Lots of physiologic processes will occur with some partial or permanent alterations of the body. Sometimes, the changes happened during the pregnancy to adapt the body to the growth and development of the fetus will lead to conditions or diseases that can stay lifelong.

One of the conditions that could develop after giving birth is the Postpartum thyroiditis. It occurs in women that had healthy thyroid before delivery, and that can last up to 18 months with permanent complications in some cases. The postpartum thyroiditis is a non-common situation that is not often recognized because some symptoms or signs are attributed to the stressful process of having a newborn, and the mood changes involved.

The postpartum thyroiditis is an inflammation process of the thyroid gland -the gland that generates the thyroid hormones-, and it usually presents two phases. Some women only present or develop the first phase, while others just show the second phase. Postpartum thyroiditis is a self-limiting condition with a euthyroid function one year after giving birth, but in some cases, complications or permanent hypothyroidism occurs.

In the first phase or stage, the thyroid gland releases more thyroid hormones, and the symptoms will be like a hyperthyroidism (overactive thyroid) such as anxiety, palpitations or rapid heartbeat, fatigue, nervousness, irritability, tremor, weight loss, insomnia, and increased sensitivity to heat. Some of these symptoms can be easily confused with the stress of having a newborn, and the lack of rest that the mother can be experiencing. This phase can be noticed from one to four months after delivery.

Later, the thyroid gland starts to become underactive, and the hypothyroidism will develop with symptoms such as lack of energy, tiredness, constipation, increase sensitivity to cold, dry skin, concentration problems, memory trouble, carelessness, aches, and general pain. This phase of hypothyroidism can occur during the fourth to eighth months after delivery and can last up to twelve months when it is solved. Sometimes, some women can develop permanent hypothyroidism or complications after this phase of postpartum hypothyroidism, and their thyroid is not able to produce the amount needed for thyroid hormones anymore.

The reason why this postpartum thyroiditis can start in some women and not in others is not clear, but some risk factors have been established with years of research. Women that have high concentrations of anti-thyroid antibodies, personal history of thyroid disease, family history of thyroid disease, an autoimmune disorder like type 1 diabetes, a history of postpartum thyroiditis, or some underlying autoimmune thyroid problem before giving birth, are the most likely to develop postpartum thyroiditis. It is believed that postpartum thyroiditis results from the immune system modifications that occur during pregnancy.

Diagnosis

After delivery, when some of the symptoms of the thyroiditis appear, the doctor will order some blood exams. One of the most important tests is the measurement of TSH (thyroid-stimulating hormone); this hormone is secreted in the anterior pituitary gland and stimulates the thyroid gland to produce and release the thyroid hormones triiodothyronine (T3) and thyroxine (T4). T4 is the other hormone to measure to make the diagnosis. Sometimes, the results do not show a problem or alteration in the blood concentration of the hormones, but if the symptoms are present or the woman has risk factors to develop the postpartum thyroiditis, the test will be performed again at third and sixth month after giving birth. If alterations of the lab results are shown, the screen could be made in two weeks.

When TSH levels are low, the hyperthyroid phase could be the answer, but this test has to be measured again to make sure is not related to other condition as Grave’s disease. If TSH levels show normal values, but symptoms are still present, maybe it is the moment when the phases of postpartum thyroiditis are changing -hyper to hypothyroidism-. An elevated lab result of TSH with normal or low T4 indicates hypothyroidism phase.

Treatment

The hyperthyroidism phase of the postpartum thyroiditis does not need treatment often. Sometimes, a beta-blocker medicine will be prescribed to control the speed of the heartbeats and some tremor. Lab screenings are necessary each four to six week for monitoring if the condition resolved itself.

But the hypothyroidism phase is treated with the synthetic thyroid hormone Levothyroxine (Synthroid, Levothroid, others) to restore the levels of the hormone thyroxine (T4) in the body, ease the symptoms and avoid complications. This medicine is given daily, at the first hour in the morning, before meals. Lab tests have to be checked every six weeks to control the evolution of the condition and to modify -increase or decrease- the Levothyroxine dosage depending on the result levels. Usually, the treatment is discontinued after one year of receiving it. If Levothyroxine is stopped, new lab screening must be performed every two months to verify that the thyroid hormones are secreted in regular doses.

When the condition is not solved in the eighteen months postpartum, and the hypothyroidism is established, is necessary to continue with the medication maybe lifelong and make new lab control test each year if modification of the symptoms does not appear before.

In the case that the mother is receiving Levothyroxine before delivery, TSH monitoring is necessary to determine the amount of medication she needs. Remember that expectant mothers that develop hypothyroidism during pregnancy or had hypothyroidism before became pregnant, they needed a higher dosage of Levothyroxine during pregnancy to supply her and the fetus growth requirements.

It is important that after delivery every woman pay attention to the symptoms that can start feeling and not attribute all of them to the stress of taking care of a newborn. Once symptoms appear, and the mother feels that the regular daily process or routine become difficult, is time to visit the doctor. Thyroid screening can be ordered and treatment, if it is necessary, can be started on time to limit the complications of the problem.

Reference:

1. Jameson, J. L., & De Groot, L. J. (2010). Endocrinology-E-Book: Adult and Pediatric. Elsevier Health Sciences