Major Thyroid Disorders During Pregnancy

Your Thyroid Gland at a Glance

The thyroid gland is a butterfly-shaped organ located in the base of the neck. It’s about 2 inches long and it is wrapped around your windpipe (trachea). It’s part of the endocrine system, and it plays a vital role in the growth, development, and metabolism of the human body. 

The thyroid makes and stores hormones (T3 and T4) that are essential to how every cell in the body functions. Among many other things, these hormones help regulate body processes such as your heart rate, blood pressure, body temperature, metabolism and even fertility. 

Thyroid Function in Pregnancy

Thyroid hormone is important during pregnancy for normal fetal development. During the first 10-12 weeks, your baby completely relies on you for thyroid hormones for brain development. This explains why your thyroid hormone requirements increase during pregnancy. 

By the end of the first trimester, your baby can already produce thyroid hormones on its own. However, it will continue to depend on you to get adequate iodine intake to make thyroid hormones. 

To avoid pregnancy issues related to thyroid hormone levels, striking a balance is vital. Studies show that deficiencies can result in several complications and even irreversible damage. Meanwhile, overproduction isn’t any better since it also poses health risks for both mother and child. 

Thyroid Disorders in Pregnancy

Thyroid disorders are relatively common, but many are unaware that they have it. 

Besides being a pre-existing disease, thyroid problems can also develop during and after pregnancy. It can even alter thyroid function in women who have no abnormalities, to begin with. Pregnancy-related hormones may cause your thyroid levels to rise making it challenging to diagnose thyroid diseases during pregnancy. This is why it’s important to get thyroid hormone levels screened before planning for pregnancy or soon after you discover that you’re pregnant. 

Moreover, women can still develop thyroid problems up to a year after giving birth. This is why post-partum doctor visits will help keep everything in check. 

Here’s a closer look at two major thyroid issues during pregnancy. 

Hypothyroidism

Hypothyroidism is a condition where the thyroid gland is unable to make enough thyroid hormones to keep the body running normally. It can stem from several causes, the most common of which is the initial presence of an autoimmune disorder called Hashimoto’s thyroiditis. It can also occur in women with inadequate treatment for hypthyroidism, or in hyperthyroid women who got over-treated with anti-thyroid medications. 

Having an underactive thyroid means crucial body processes slow down. Mild hypothyroidism may show no symptoms and even if there was, it may be attributed to pregnancy. However, in severe cases, complications are more likely to occur. Maternally, it can increase the risk of miscarriage, pre-eclampsia, congestive heart failure, placental abnormalities, and postpartum bleeding. If left untreated or if poorly managed, these complications can be life-threatening to you and your baby.

Inadvertently, hypothyroidism can also impair a baby’s brain development. Babies who are born with hypothyroiditis will suffer from cognitive, neurological, and developmental abnormalities. They are also likely to be born prematurely with low birth weight. 

Planning ahead and discussing thyroid status with your primary care physician and OB helps prevent complications, especially among high-risk women. This involves proper screening tests, optimised treatment prior to becoming pregnant, and close monitoring throughout your pregnancy. For hypothyroidism, the goal is to provide adequate thyroid hormone replacement.

New mothers must ensure that they get follow-up medical attention even after delivery because thyroid conditions don’t usually resolve by itself. Some may even develop postpartum thyroiditis, which is the occurrence of a thyroid problem in the first year after pregnancy. Hence, therapy may have to be continued as necessary. 

Hyperthyroidism

Normally, pregnancy hormones can cause the thyroid gland to slightly enlarge during pregnancy. However, in hyperthyroidism, there is an excess production of thyroid hormones which results in a goiter. This complication in pregnancy is often linked to an autoimmune disorder called Grave’s disease. 

This condition mostly affects young to middle-aged women in their child-bearing years, and it also tends to run in families. It may first appear during pregnancy or it may already be a pre-existing condition. Nevertheless, Grave’s disease poses a risk for both mother and baby if left unmanaged. 

Pregnant women with uncontrolled hyperthyroidism may experience a dangerous rise in blood pressure called pre-eclampsia. They are also at risk for miscarriages, pre-term delivery, and congestive heart failure. For some women, they may experience a sudden worsening of symptoms which is a medical emergency referred to as a thyroid storm. 

Furthermore, hyperthyroidism also carries a high risk for the baby with complications such as  intrauterine growth retardation, birth defects, and increased incidence of stillbirths. 

For the proper treatment of hyperthyroidism, your doctor will first review your symptoms and do appropriate screening tests to measure thyroid hormone levels. This condition entails frequent monitoring throughout your pregnancy. Medications will also be prescribed to control thyroid hormone production. Radioactive iodine is also a common treatment for hyperthyroidism, but it is not advised in pregnant and breastfeeding women. In some cases, surgery is needed to remove part of your thyroid, especially if there is an overactive nodule. 

Diagnosing the Problem

Since the symptoms of thyroid problems are closely similar to that of pregnancy, a correct diagnosis can be easily missed. 

The challenge with pinpointing thyroid problems in pregnancy is distinguishing the symptoms of the disease from that which are typical in pregnancy. Depending on the severity of the condition, a correct diagnosis can be easily missed. So, if you notice that something doesn’t feel right, alert your doctor as soon as possible. 

Diagnosis can be made through blood tests and imaging tests. Your blood can be extracted to tst for TSH (Thyroid Stimulating Hormone), T3, and T4 levels. Checking for thyroid antibodies may also be done to check for any autoimmune disorders – a condition where your immune system attacks the thyroid gland by mistake. 

Imaging tests may also be done to arrive at a diagnosis. An ultrasound of the thyroid is used to detect the presence of nodules, it is also a necessary tool for disease management. A thyroid scan and uptake can also be done to check the size, shape and position of the thyroid. However, this is advised against pregnant and breastfeeding women because it uses radioactive materials. If there is a lump or nodule found during these diagnostic tests, a needle aspiration biopsy will be done where a small sample of that growth is removed to check if it is cancerous or not.

Women with thyroid problems can increase their chances of a healthy pregnancy if they get early prenatal care and closely work with healthcare providers in disease management.  Get in touch with Dr. Pamela Tan today for a thorough evaluation and customised medical advice.